greater anteroposterior pelvic diameter, especially at lower levels. enabling the limb to swing clear of the pelvis. The neck also provides
The sacrum also displays metrical sexual differences. Female sacra a lever for the action of the muscles acting about the hip joint, which
are less curved, the curvature being most marked between the first and are attached to the proximal femur. The neck–shaft angle is widest at
second segments and the third and fifth, with an intervening flatter birth and diminishes gradually until the age of 10 years (Birkenmaier
region. Male sacra are more evenly curved, and relatively long and et al 2010); it is smaller in females. The neck is laterally rotated with
narrow, and more often exceed five segments (by addition of a lumbar respect to the shaft (angle of anteversion) some 10–15°, although
or coccygeal vertebra). The sacral index compares sacral breadth values of this angle vary between individuals and between populations
(between the most anterior points on the auricular surfaces) with length (Eckhoff et al 1994). The contours of the neck are rounded; the upper
(between midpoints on the anterior margins of the promontory and surface is almost horizontal and slightly concave, while the lower is
apex): average values for males and females are 105% and 115%, respec- straighter but oblique, directed inferolaterally and backwards to the
tively. Auricular surfaces are relatively smaller and more oblique in shaft near the lesser trochanter. On all aspects the neck expands as it
females, but extend on to the upper three sacral vertebrae in both sexes. approaches the articular surface of the head. The anterior surface of
The dorsal auricular border is more concave in females. Many differ- the neck is flat and marked at the junction with the shaft by a rough
ences may be summarized in the generalization that the pelvic cavity is intertrochanteric line. The posterior surface, facing posteriorly and
longer and more conical in males, and shorter and more cylindrical in superiorly, is transversely convex, and concave in its long axis; its junc-
females; the axis is curved in both. Differences are greater at the inferior tion with the shaft is marked by a rounded intertrochanteric crest.


aperture than at the brim, where in absolute measurements males are There are numerous vascular foramina, especially anteriorly and
not as different from females as sometimes stated. posterosuperiorly.
In forensic practice, identification of human skeletal remains (which The anterior surface is intracapsular, the capsule attaching laterally
are sometimes fragmentary) usually involves determination of sex, and to the intertrochanteric line. Facets, often covered by extensions of
this is most reliably established from an examination of the pelvis. Even articular cartilage, and various imprints frequently occur here. These
fragments of the pelvis may be useful in this respect. Several studies of facets may sometimes be associated with squatting. On the posterior
metrical characteristics in various pelvic regions have been made, surface the capsule does not reach the intertrochanteric crest; little more
leading to the establishment of various indices. The ilium has received than the medial half of the neck is intracapsular. The anterior surface
particular attention, e.g. one index compares the pelvic and sacroiliac adjoining the head and covered by cartilage is related to the iliofemoral
parts of the bone. A line is extended back from the iliopubic ramus to ligament. A groove, produced by the tendon of obturator externus as it
the nearest point on the anterior auricular margin and thence to the approaches the trochanteric fossa, spirals across the posterior surface of
iliac crest. The auricular point divides this chilotic line into anterior the neck of the femur in a proximolateral direction.
(pelvic) and posterior (sacral) segments, each expressed as a percentage
of the other. Chilotic indices display reciprocal values in the sexes: the greater trochanter
pelvic part of the chilotic line is predominant in females, and the sacral The greater trochanter is large and quadrangular, projecting up from the
part in males. Detailed metrical studies of the ilium have indicated its junction of the neck and shaft (see Fig. 80.13). Its posterosuperior
limited reliability in ‘sexing’ pelves. However, the higher incidence and region projects superomedially to overhang the adjacent posterior
definition of the female pre-auricular sulcus is recognized. The desira- surface of the neck and here its medial surface presents the rough tro-


bility of correlating all available metrical data is to be emphasized; chanteric fossa. The proximal border of the trochanter lies approxi-
when a range of pelvic data can be combined, especially if they are mately a hand’s breadth below the iliac tuberculum, level with the
metrical, 95% accuracy should be achieved. Complete accuracy has centre of the femoral head. It has an anterior rough impression. Its
been claimed when the rest of the skeleton is available. Assessment of lateral surface, continuous distally with the lateral surface of the femoral
sex from isolated and often incomplete human remains is less reliable. shaft, is crossed anteroinferiorly by an oblique, flat strip, which is wider
For further details, consult Mays (1998) and Brothwell and Pollard above. This surface is palpable, especially when the muscles are relaxed.
(2001). The trochanteric fossa occasionally presents a tubercle or exostosis.
lesser trochanter
FEMUR The lesser trochanter is a conical posteromedial projection of the shaft
at the posteroinferior aspect of its junction with the neck. Its summit
The femur is the longest and strongest bone in the human body (Figs and anterior surface are rough, but its posterior surface, at the distal
80.11–80.12). Its length is associated with a striding gait, and its end of the intertrochanteric crest, is smooth. It is not palpable.


Bones
1349
08
retPahc
Neck
B
A
Sacrospinous ligament;
Fovea for ligament of head Rectus femoris
ischiococcygeus
Trochanteric fossa Iliopectineal bursa
Head
Greater trochanter Pectineus
Neck Obturator externus Gluteus minimus
Intertrochanteric line
Adductor longus Vastus lateralis
Lesser trochanter Adductor brevis Iliopsoas
Gracilis
Vastus intermedius
Adductor magnus
Vastus medialis
Quadratus femoris
Biceps femoris
Semimembranosus
Shaft
Articularis genus
Vastus medialis Quadriceps femoris
Adductor magnus
Biceps femoris
Fibular collateral ligament
Adductor tubercle
Sartorius Lateral patellar retinaculum
Medial epicondyle Lateral epicondyle
Gracilis
Extensor digitorum longus
Patellar surface
Fig. 80.11 The femur, anterior aspect. A, Osseous features. B, Muscle attachments. (With permission from Waschke J, Paulsen F (eds), Sobotta Atlas of
Human Anatomy, 15th ed, Elsevier, Urban & Fischer. Copyright 2013.)
intertrochanteric line indistinct. The posterolateral surface is bounded posteriorly by the
The intertrochanteric line, a prominent ridge at the junction of the broad, rough linea aspera, usually a crest with lateral and medial edges.
anterior surfaces of the neck and shaft, descends medially from a tuber- Its subjacent compact bone is augmented to withstand compressive
cle on the upper part of the anterior aspect of the greater trochanter to forces, which are concentrated here by the anterior curvature of the
a point on the lower border of the neck, anterior to the lesser trochanter, shaft. The linea aspera gives attachment to adductor longus, intermus-
where there may also be a tubercle. This line is the lateral limit of the cular septa and the short head of biceps femoris, all inseparably blended
hip joint capsule anteriorly. The upper and lower bands of the iliofemo- at their attachments. Perforating arteries cross the linea aspera laterally


ral ligament are attached to its proximal and distal ends and the associ- under tendinous arches in adductor magnus and biceps femoris. Nutri-
ated tubercles. Distally, it is continuous with the spiral line. ent foramina, directed proximally, appear in the linea aspera, varying
in number and site, one usually near its proximal end, a second usually
intertrochanteric crest near its distal end. The posteromedial surface, smooth like the others,
The intertrochanteric crest, a smooth and prominent ridge at the junc- is bounded in front by the indistinct medial border and behind by the
tion of the posterior surface of the neck with the shaft, descends medi- linea aspera. In its proximal third the shaft has a fourth, posterior
ally from the posterosuperior angle of the greater trochanter to the surface, bounded medially by a narrow, rough spiral line that is continu-
lesser trochanter. A little above its centre is a low, rounded quadrate ous proximally with the intertrochanteric line and distally with the
tubercle. It is covered by gluteus maximus, from which it is separated, medial edge of linea aspera. Laterally, this surface is limited by the
medial to the tubercle, by quadratus femoris and the upper border of broad, rough gluteal tuberosity, ascending a little laterally to the greater
adductor magnus. trochanter and descending to the lateral edge of the linea aspera. In its
distal one-third, the posterior surface of the shaft presents a further
gluteal tuberosity surface, the popliteal surface (see below) between the medial and lateral
The gluteal tuberosity may be an elongated depression or a ridge. It may supracondylar lines. These lines are continuous above with the corre-
at times be prominent enough to merit the title of a third trochanter. sponding edges of the linea aspera. The lateral line is most distinct in
its proximal two-thirds, where the short head of biceps femoris and
Shaft lateral intermuscular septum are attached. Its distal third has a small,
The shaft is surrounded by muscles and is impalpable (see Figs 80.11– rough area for the attachment of plantaris, often encroaching on the


80.12). The distal anterior surface, for 5–6 cm above the patellar articu- popliteal surface. The medial line is indistinct in its proximal two-
lar surface, is covered by a suprapatellar bursa, between bone and thirds, where vastus medialis is attached. Distally, the femoral vessels
muscle. The distal lateral surface is covered by vastus intermedius. The entering the popliteal fossa from the adductor canal cross the medial
medial surface, devoid of attachments, is covered by vastus medialis. line obliquely. Further distally, the line is often sharp for 3 or 4 cm
The shaft is narrowest centrally, expanding a little at its proximal proximal to the adductor tubercle.
end, and substantially more at its distal end. Its long axis makes an The popliteal surface, triangular in outline, lies between the medial
angle of approximately 10° with the vertical, and diverges 5–7° from and lateral supracondylar lines. In its distal medial part, it is rough and
the long axis of the tibia. Its middle one-third has three surfaces and slightly elevated. Forming the proximal part of the floor of the popliteal
borders. The extensive anterior surface, smooth and gently convex, is fossa, the popliteal surface is covered by a variable amount of fat that
between the lateral and medial borders, which are both round and separates the popliteal artery from bone. The superior medial genicular


Pelvic girdle, gluteal region and thigh
1350
9
noitceS
A B
Head Obturator internus
Fovea of ligament of head Piriformis
Greater trochanter Rectus femoris
Neck Obturator externus
Quadrate tubercle Gluteus medius
Intertrochanteric crest Obturator internus
Gluteus minimus
Lesser trochanter Trochanteric bursa of
gluteus medius
Pectineal line (spiral line) Levator ani
Gluteal tuberosity Quadratus femoris
Subcutaneous Deep transverse perineal muscle
trochanteric bursa
Gluteus maximus Gemellus superior
Pectineus
Sciatic bursa of obturator internus
Adductor magnus
Gemellus inferior
Adductor brevis Semitendinosus
Lateral lip
Linea aspera Vastus medialis lliopsoas
Medial lip
Vastus intermedius
Adductor longus
Biceps femoris
Vastus lateralis
Lateral supracondylar line
Medial supracondylar line
Adductor magnus
Popliteal surface
Medial subtendinous
Gastrocnemius bursa of gastrocnemius
Lateral epicondyle Adductor tubercle Plantaris Semimembranosus
Fibular collateral ligament
Sartorius
Lateral condyle Medial condyle Biceps femoris Gracilis
Intercondylar fossa Intercondylar line Popliteus Semitendinosus
Semimembranosus
Fig. 80.12 The femur, posterior aspect. A, Osseous features. B, Muscle attachments. (With permission from Waschke J, Paulsen F (eds), Sobotta Atlas
of Human Anatomy, 15th ed, Elsevier, Urban & Fischer. Copyright 2013.)
Trochanteric fossa Head Patellar surface
Fovea for
ligament of head
Greater trochanter
Neck Medial epicondyle
Quadrate tubercle
Lateral epicondyle
Intertrochanteric crest Medial condyle
Lateral condyle
Lesser trochanter
Intercondylar fossa
Gluteal tuberosity


Fig. 80.14 The distal end of the femur, articular surface. (With permission
from Waschke J, Paulsen F (eds), Sobotta Atlas of Human Anatomy, 15th
Pectineal line (spiral line)
ed, Elsevier, Urban & Fischer. Copyright 2013.)
Linea aspera, medial lip
lateral condyle but is separated from bone by the attachment of plantaris
to the distal part of the lateral supracondylar line.
Fig. 80.13 The proximal end of the femur, posterior aspect. (With
permission from Waschke J, Paulsen F (eds), Sobotta Atlas of Human distal end
Anatomy, 15th ed, Elsevier, Urban & Fischer. Copyright 2013.) The distal end of the femur is widely expanded as a bearing surface for
transmission of weight to the tibia (Fig. 80.14). It bears two massive
condyles, which are partly articular. Anteriorly, the condyles are conflu-
artery, a branch of the popliteal artery, arches medially above the medial ent and continue into the shaft; posteriorly, they are separated by a deep
condyle. It is separated from bone by the medial head of gastrocnemius. intercondylar fossa and project beyond the plane of the popliteal
The latter is attached a little above the condyle; further distally, there surface. The articular surface is a broad area, like an inverted U, for the
may be a smooth facet underlying a bursa for the medial head of patella and the tibia. The patellar surface extends anteriorly on both
gastrocnemius. More medially, there is often an imprint proximal to condyles, especially the lateral. It is transversely concave, vertically
the articular surface; in flexion, this is close to a rough tubercle on convex and grooved for the posterior patellar surface. The tibial surface
the medial tibial condyle for the attachment of semimembranosus. The is divided by the intercondylar fossa but is anteriorly continuous with
superior lateral genicular artery arches up laterally proximal to the the patellar surface. Its medial part is a broad strip on the convex


Bones
1351
08
retPahc
inferoposterior surface of the medial condyle, and is gently curved with
a medial convexity. Its lateral part covers similar aspects of the lateral
condyle but is broader and passes straight back. The tibial surfaces are
convex in all directions. The medial and lateral tibial surfaces have dis-
similar anteroposterior curvatures. However, views differ as to the exact
representation of these differences. One view holds that in both tibial
portions of the femoral condyles, the sagittal radius of curvature is ever-
decreasing (a ‘closing helix’). More recently, it has been suggested that
the medial articular surface describes arcs of two circles. The more
posterior has a smaller radius. Laterally, there may only be one arc of
1
fixed curvature with a radius similar to that of the posterior arc of the
medial femoral articular surface. These differences are believed to be
important determinants of knee joint motion.
2
Patellar surface
The patellar surface extends more proximally on the lateral side. Its
3
proximal border is therefore oblique and runs distally and medially,
separated from the tibial surfaces by two faint grooves that cross the 4
condyles obliquely. The lateral groove is the more distinct. It runs lat- 5
erally and slightly forwards from the front of the intercondylar fossa
and expands to form a faint triangular depression, resting on the ante-
6
rior edge of the lateral meniscus when the knee is fully extended. The
medial groove is restricted to the medial part of the medial condyle and
rests on the anterior edge of the medial meniscus in full extension.
Where it ceases, the patellar surface continues back to the lateral part
of the medial condyle as a semilunar area adjoining the anterior region Fig. 80.15 The distal end of the femur, lateral aspect. Key: 1, attachment
of the intercondylar fossa. This area articulates with the medial vertical of plantaris; 2, attachment of lateral head of gastrocnemius; 3, lateral
facet of the patella in full flexion; its outline is indistinct in most epicondyle; 4, attachment of fibular collateral ligament; 5, groove for


femora. In habitual squatters articular cartilage may extend to the lateral popliteus in full flexion; 6, attachment of popliteus.
aspect of the lateral condyle under vastus lateralis.
and the medullary cavity most capacious. Proximally and distally, the
Intercondylar fossa compact wall becomes progressively thinner, and the cavity gradually
The intercondylar fossa separates the two condyles distally and behind. fills with trabecular bone. The extremities, especially where articular,
In front, the distal border of the patellar surface limits it, and behind consist of trabecular bone within a thin shell of compact bone, their
an intercondylar line limits it, separating it from the popliteal surface. trabeculae being disposed along lines of greatest stress. At the proximal
It is intracapsular but largely extrasynovial. Its lateral wall, the medial end, the main trabeculae form a series of plates orthogonal to the
surface of the lateral condyle, bears a flat posterosuperior impression articular surface, converging to a central dense wedge, which is sup-
that spreads to the floor of the fossa near the intercondylar line for the ported by strong trabeculae passing to the sides of the neck, especially
proximal attachment of the anterior cruciate ligament. The medial wall along its upper and lower profiles (Fig. 80.16). Force applied to the
of the fossa, i.e. the lateral surface of the medial condyle, bears a similar femoral head is therefore transmitted to the wedge and from there to
larger area, but far more anteriorly, for the proximal attachment of the the junction of the neck and shaft. This junction is strengthened by
posterior cruciate ligament. Both impressions are smooth and largely dense trabeculae extending laterally from the lesser trochanter to the
devoid of vascular foramina, whereas the rest of the fossa is rough and end of the superior aspect of the neck, thus resisting tensile or shearing
pitted by vascular foramina. A bursal recess between the ligaments may forces applied to the neck through the head (Fig. 80.17). Tensile and
ascend to the fossa. The capsular ligament and, laterally, the oblique compressive tests indicate that axial trabeculae of the femoral head


popliteal ligament are attached to the intercondylar line. The infrapatel- withstand much greater stresses than peripheral trabeculae. A smaller
lar synovial fold is attached to the anterior border of the fossa. bar across the junction of the greater trochanter with the neck and shaft
resists shearing produced by muscles attached to it. These two bars are
Lateral condyle proximal layers of arches between the sides of the shaft and transmit to
The lateral condyle (see Fig. 80.14) is larger anteroposteriorly than the it forces applied to the proximal end. A thin vertical plate, the so-called
medial. Its most prominent point is the lateral epicondyle to which the calcar femorale, ascends from the compact wall near the linea aspera
fibular collateral ligament is attached (Fig. 80.15). A short groove, into the trabeculae of the neck (see Fig. 80.17). Medially, it joins the
deeper in front, separates the lateral epicondyle inferiorly from the posterior wall of the neck; laterally, it continues into the greater tro-
articular margin. This groove allows the tendon of popliteus to run deep chanter, where it disperses into general trabecular bone. It is thus in a
to the fibular collateral ligament and insert inferior and anterior to the plane anterior to the trochanteric crest and base of the lesser trochanter.
ligament insertion. Adjoining the joint margin is a strip of condyle, Dixon (1910) demonstrated that the trabecular framework of the proxi-
1 cm broad. It is intracapsular and covered by synovial membrane mal femur was spiral, and that the ‘arches’ were simplified sectional
except for the attachment of popliteus. profiles of this spiral. At the distal end of the femur, trabeculae spring
The medial surface is the lateral wall of the intercondylar fossa. Its from the entire internal surface of compact bone, descending perpen-
lateral surface projects beyond the shaft. Part of the lateral head of dicular to the articular surface. Proximal to the condyles these are
gastrocnemius is attached to an impression posterosuperior to the strongest and most accurately perpendicular. Horizontal planes of


lateral epicondyle. trabecular bone, arranged like crossed girders, form a series of cubical
compartments.
Medial condyle
The medial condyle has a bulging, convex medial aspect, which is easily Muscle attachments
palpable. Proximally, its adductor tubercle, which may only be a facet The greater trochanter provides attachment for gluteus minimus and
rather than a projection, receives the tendon of adductor magnus. The medius. Gluteus minimus is attached to its rough anterior impression
medial prominence of the condyle, the medial epicondyle, is antero- and gluteus medius to its lateral oblique strip. The bone is separated
inferior to the tubercle. The lateral surface of the condyle is the medial from the tendon of gluteus medius by a bursa. The area behind it is
wall of the intercondylar fossa. The condyle projects distally so that, covered by deep fibres of gluteus maximus, with part of its trochanteric
despite the obliquity of the shaft, the profile of the distal end is almost bursa interposed. The tendon of piriformis is attached to the upper
horizontal. A curved strip, 1 cm wide and adjoining the medial articular border of the trochanter and the common (tricipital) tendon of obtura-
margin, is covered by synovial membrane and is inside the joint capsule. tor internus and the gemelli is attached to its medial surface. The tro-
Proximal to this, the medial epicondyle receives the tibial collateral chanteric fossa receives the tendon of obturator externus. Psoas major
ligament. is attached to the summit and anteromedial surface of the lesser tro-
chanter. Iliacus is attached to the medial or anterior surface of its base,
Structure descending a little behind the spiral line as its tendon fuses with that
The femoral shaft is a cylinder of compact bone with a large medullary of psoas major. Adductor magnus (upper part) passes over its posterior
cavity. The wall is thick in its middle third, where the femur is narrowest surface, sometimes separated by an interposed bursa.


Pelvic girdle, gluteal region and thigh
1352
9
noitceS
Fig. 80.16 A coronal section
through the left hip joint.
Lunate surface
Tensor fasciae latae (With permission from
Joint capsule Waschke J, Paulsen F (eds),
Head of femur Gluteus medius Sobotta Atlas of Human
Anatomy, 15th ed, Elsevier,
Acetabular fossa
Gluteus minimus Urban & Fischer. Copyright
Ligament of head of femur
2013.)
Fovea for ligament of head
Obturator internus Trochanteric fossa
Greater trochanter
Neck of femur
Tendon of gluteus maximus
Acetabular labrum
Trochanteric bursa of gluteus maximus
Trochanteric bursa of gluteus medius
Obturator externus
Iliotibial tract
Tendon of iliopsoas
Lesser trochanter Vastus lateralis
Head of femur Greater trochanter tor magnus. Distal to this, adductor magnus is attached to the linea
aspera and, by an aponeurosis, to the proximal part of the medial
supracondylar ridge. Its remaining fibres form a large tendon attached
to the adductor tubercle, with an aponeurotic expansion to the distal
part of the medial supracondylar ridge.
Pectineus and adductor brevis are attached to the posterior femoral
surface between the gluteal tuberosity and spiral line. The pectineal
attachment is a line, sometimes slightly rough, from the base of the
lesser trochanter to the linea aspera. Adductor brevis is attached lateral
to pectineus and beyond this to the proximal part of the linea aspera,
medial to adductor magnus. Adductor longus, intermuscular septa and
the short head of biceps femoris are attached to the linea aspera. Vastus
lateralis has a linear attachment from the anterior surface of the base
of the greater trochanter to the proximal end of the gluteal tuberosity,
Compact bone and along the lateral margin of the latter to the proximal half of the
lateral edge of the linea aspera. Vastus medialis is attached from the


distal end of the intertrochanteric line along the spiral line to the medial
edge of the linea aspera and thence to the medial supracondylar line,
which also receives many fibres from the aponeurotic attachments of
Calcar femorale adductor magnus.
The medial head of gastrocnemius is attached to the posterior surface
Lesser trochanter a little above the medial condyle. The short head of biceps femoris is
attached to the proximal two-thirds of the lateral supracondylar line.
Plantaris attaches to the line distally. Vastus medialis is attached to the
proximal two-thirds of the medial supracondylar line.
Part of the lateral head of gastrocnemius is attached posterosuperi-
orly to the lateral epicondyle. Popliteus is attached anteriorly in the
groove on the outer aspect of the lateral epicondyle. Its tendon passes
Spongy (trabecular) bone deep to the fibular collateral ligament (see Fig. 80.15). The tendon lies
in the groove in full knee flexion; in extension it crosses the articular
margin and may form an impression on it.
vascular supply
The blood supply of the femoral head is derived from an arterial ring
around the neck, just outside the attachment of the fibrous capsule,
constituted by the medial and lateral circumflex femoral arteries with
minor contributions from the superior and inferior gluteal vessels (see
‘Trochanteric anastomosis’) (Fig. 80.18). From this ring, ascending cer-
vical branches pierce the capsule (under its zona orbicularis) to ascend
the neck beneath the reflected synovial membrane. These vessels
become the retinacular arteries and form a subsynovial intracapsular
anastomosis. Here the vessels are at risk with a displaced fracture of the
Fig. 80.17 A coronal section through the proximal end of the femur
femoral neck. Interruption of blood supply in this way can lead to
showing the trabecular architecture, calcar femorale and variations in
avascular necrosis of the femoral head. If the fracture is intracapsular,
cortical thickness. (With permission from Waschke J, Paulsen F (eds),


Sobotta Atlas of Human Anatomy, 15th ed, Elsevier, Urban & Fischer. not only is the intraosseous blood supply damaged but the retinacular
Copyright 2013.) vessels are also vulnerable. If the fracture is extracapsular, the retinacular
vessels will remain intact and avascular necrosis of the femoral head is
much less likely. The ascending cervical vessels give off metaphysial
The most proximal fibres of vastus lateralis are attached to the proxi- branches that enter the neck, while the intracapsular ring gives off
mal end of the intertrochanteric line, and those of vastus medialis to lateral and inferior epiphysial branches. A small medial epiphysial
the distal end. Quadratus femoris is attached to the quadrate tubercle supply, of importance in early childhood, reaches the head along the
and the immediately distal bone. Vastus intermedius is attached to the ligament of the head of femur by the acetabular branches of the obtura-
anterior and lateral surfaces of the proximal three-quarters of the tor and medial circumflex femoral arteries, which anastomose with
femoral shaft. Slips of articularis genus are attached distal to this. the other epiphysial vessels. During growth, the epiphysial plate sepa-
The gluteal tuberosity receives the deeper fibres of the distal half of rates the territories of the metaphysial and epiphysial vessels; these
gluteus maximus and, at its medial edge, the uppermost fibres of adduc- vessels anastomose freely after osseous union of the head and neck.


Joints
1353
08
retPahc
Joins shaft
Abdominal
eighteenth to
aorta Inferior epigastric nineteenth
Common artery year
iliac artery
Median Iliolumbar
Joins shaft
sacral artery artery
eighteenth
Deep circumflex
L5 vertebra iliac artery year
End of Fourth Fourteenth
Internal Superior gluteal artery At birth first year year Puberty year
iliac artery Inguinal ligament
Lateral sacral artery
Lateral circumflex
Obturator artery femoral artery Joins shaft
eighteenth
Medial circumflex to twentieth
Inferior gluteal artery femoral artery year
Profunda Fig. 80.19 Stages in ossification of the femur (not to scale).
femoris artery
External pudendal artery
Femoral artery
inferomedial part of the articular surface is on the neck. The medial
epiphysial margin later grows over this part of the articular surface.
Perforating branches of Thus, the mature epiphysis is a hollow cup on the summit of the neck.
profunda femoris artery The epiphysial line follows the articular margin except where it is sepa-
Lateral circumflex
rated superiorly from the articular surface by a non-articular area where
femoral artery
blood vessels enter the head (Trueta 1957). The epiphyses fuse inde-
pendently: the lesser trochanter soon after puberty, followed by the
greater trochanter. The capital epiphysis fuses in the fourteenth year in
females and seventeenth year in males. The epiphysis at the distal end
fuses in the sixteenth year in females, and eighteenth year in males. The
Descending genicular artery distal epiphysial plate traverses the adductor tubercle.
Growth plate considerations
Fig. 80.18 The collateral circulation around the hip and upper thigh, Trauma to any epiphysial plate can lead to bony union between epiphy-
anterior aspect. sis and metaphysis, and so cause premature cessation of growth. Any
surgery in the hip region in children can injure the growth plate, result-
ing in abnormal proximal femoral development. In the case of fractures


Observations of developmental patterns of this supply in late fetal and involving the epiphysis, expeditious restoration of normal bony align-
early postnatal periods have revealed that although medial and lateral ment is essential in order to minimize the risk of subsequent abnormal
circumflex femoral arteries at first contribute equally, two major growth.
branches of the medial provide the final supply, both posterior to the The growth plate represents a line of weakness and predisposes to
neck. The supply from the lateral circumflex artery diminishes and fracture from injury. Such acute injuries affecting the capital epiphysis
the arterial ring is interrupted. As the femoral neck elongates, the extra- are uncommon. However, a more chronic fracture through the capital
capsular circle becomes more distant from the epiphysial part of epiphysis occurs in slipped capital femoral epiphysis (SCFE) (see Fig.
the head. 81.9). The condition affects pubescent adolescents, especially males.
The trochanteric regions and subtrochanteric shaft are supplied by Endocrinological abnormality may be related. The femoral head epi-
the trochanteric and cruciate arterial anastomoses. More distally in the physis displaces posteriorly off the femoral neck. If it heals in this
shaft, nutrient foramina, directed proximally, are found in the linea position, lower limb deformity and restricted hip movement occur. A
aspera, varying in number and site: one is usually near its proximal end classic hallmark is obligatory lateral rotation of the femur as the hip is
and a second usually near its distal end. The main nutrient artery is flexed. Treatment varies according to the time taken for the ‘slip’ to
usually derived from the second perforating artery (see ‘Profunda occur. Normal anatomical restoration is not attempted because of an
femoris artery’). If two nutrient arteries occur, they may branch from increased incidence of avascular necrosis. The position of the femoral
the first and third perforators. Periosteal vessels arise from the perfora- head may be accepted as it is and fixed with screws in this position to
tors and from the profunda femoris artery, and run circumferentially stop further displacement. This treatment will deliberately cause pre-
rather than longitudinally. The distal metaphysis has many vascular mature growth plate fusion and so prevent future ‘slippage’. Since the


foramina. Arterial supply here is from the genicular anastomosis. For distal femoral growth plate accounts for most of the normal increase
further details, consult Crock (1980, 1996). in longitudinal growth of the femoral shaft, an acceptable limb length
In general, the pattern of venous drainage of the head and neck cor- difference usually results.
responds to that of the arteries, though there may be a single large cervi- Infection of bone in neonates and young children tends to arise via
cal vein posteroinferiorly. bacteria in the blood stream that usually ‘seed’ in the metaphysial
region, probably as a consequence of the vascular ‘arcade’ arrangement
innervation of arteries in this part of the bone. The proximal femoral growth plate
The periosteal innervation is derived proximally from nerves that supply is intra-articular. As a result, infection in the proximal femoral meta-
the hip joint, distally from those supplying the knee, and in all areas physis can spread into the joint and result in a septic arthritis that can
from nerves that innervate muscles attached to the bone. destroy the hip joint permanently.
The distal end of the femur is the only epiphysis in which ossific-
ossification ation consistently starts just before birth; the phenomenon therefore
The femur ossifies from five centres: in the shaft, head, greater and lesser serves as a reliable indicator of the gestational maturity of a stillborn
trochanters and the distal end (Fig. 80.19). Other than the clavicle, it baby. Since the epiphysial plate is level with the adductor tubercle, the
is the first long bone to ossify. The process starts in the mid-shaft in the epiphysis is partly extra-articular. Operations here may damage the
seventh prenatal week and extends to produce a miniature shaft that is distal epiphysial cartilage in children and result in subsequent shorten-
largely ossified at birth. Secondary centres appear in the distal end ing of the leg.
(from which the condyles and epicondyles are formed) during the
ninth month, in the head during the first six months after birth
JOINTS
(Fig. 80.20), in the greater trochanter during the fourth year and in
the lesser trochanter between the twelfth and fourteenth years. In the


infant, the femoral head is entirely cartilaginous; it cannot be seen on PUBIC SYMPHYSIS
plain radiographs and is best visualized using ultrasound (Fig. 80.21).
The centre in the cartilaginous head is restricted to it until the tenth The pubic bones meet in the midline at the pubic symphysis, a second-
year, so that the epiphysial line (see Fig. 80.7) is horizontal and the ary cartilaginous joint (see Fig. 80.4).


08
retPahc
Pelvic girdle, gluteal region and thigh
Fig. 80.21 An ultrasound image of a 4-week-old baby taken in the lateral
Fig. 80.20 A radiograph of the pelvis of a 9-month-old infant showing the position and demonstrating the cartilaginous femoral head (yellow arrow)
centre of ossification of the femoral epiphysis (arrow). (Courtesy of Mr and edge of the acetabulum (red arrow). (Courtesy of Mr Christopher
Christopher Edward Bache.) Edward Bache.)
1353.e1


Pelvic girdle, gluteal region and thigh
1354
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Articulating surfaces The articulating surfaces are the medial (sym- anteriorly than posteriorly in adults. The thinner cartilage on the iliac
physial) surfaces of the pubic bones, each covered by a thin layer of surface is also hyaline in type, as confirmed by the presence of type II
tightly adherent hyaline cartilage (surface growth cartilage in the collagen.
young). The junction is not flat but is marked by reciprocal crests and
papillae. Theoretically, this would resist shearing. The surfaces of hyaline Fibrous capsule The capsule is attached close to both articular
cartilage are connected by fibrocartilage, varying in thickness and con- margins.
stituting the interpubic disc. The symphysis often contains a cavity,
probably due to absorption. It rarely appears before the tenth year and Ligaments The ligaments of the sacroiliac joint are the anterior,
is non-synovial. The cavity, which is better developed in females, is interosseous and posterior sacroiliac, iliolumbar, sacrotuberous and
usually posterosuperior but may reach the front or even occupy most sacrospinous ligaments.
of the cartilage.
Anterior sacroiliac ligament The anterior sacroiliac ligament (see Fig.
Ligaments The interpubic disc is strengthened anteriorly by several 80.9A), an anteroinferior capsular thickening, is particularly well devel-
interlacing collagenous fibrous layers, passing obliquely from bone to oped near the arcuate line and the posterior inferior iliac spine, where
bone, decussating with fibres of the external oblique aponeuroses and it connects the third sacral segment to the lateral side of the pre-
the medial tendons of the recti abdominis. These layers constitute the auricular sulcus. It is thin elsewhere.
anterior pubic ligament. There are less well developed posterior fibres,
sometimes named the posterior pubic ligament. The main ligaments of Interosseous sacroiliac ligament The interosseous sacroiliac liga-
the joint are the superior and arcuate pubic ligaments. The superior ment is the major bond between the bones, filling the irregular space


pubic ligament connects the bones above, extending to the pubic tuber- posterosuperior to the joint. The posterior sacroiliac ligament covers it
cles. The arcuate pubic ligament, a thick arch of fibres, connects the superficially. Its deeper part has superior and inferior bands passing
lower borders of the symphysial pubic surfaces bounding the pubic from depressions posterior to the sacral auricular surface to those on
arch. It blends superiorly with the interpubic disc and extends laterally the iliac tuberosity. These bands are covered by, and blend with, a
attached to the inferior pubic rami. Its inferior edge is separated from more superficial fibrous sheet connecting the posterosuperior margin
the anterior border of the perineal membrane by an opening, which is of a rough area posterior to the sacral auricular surface to the corre-
traversed by the deep dorsal vein of the penis or clitoris. sponding margins of the iliac tuberosity. This sheet is often partially
divided into superior and inferior parts, the former uniting the supe-
Vascular supply The pubic symphysis is supplied by pubic branches rior articular process and lateral crest on the first two sacral segments
of the obturator, superficial external pudendal and inferior epigastric to the neighbouring ilium as a short posterior iliac ligament (see Fig.
arteries. 43.68).
Innervation The pubic symphysis is innervated by branches from the Posterior sacroiliac ligament The posterior sacroiliac ligament (see
iliohypogastric, ilioinguinal and pudendal nerves. Fig. 80.9B) overlies the interosseous ligament: the dorsal rami of the
sacral spinal nerves and vessels intervene. It consists of several weak
Factors maintaining stability The interpubic disc and the superior fasciculi connecting the intermediate and lateral sacral crests to the
and arcuate ligaments are the main stabilizing factors of the pubic posterior superior iliac spine and posterior end of the internal lip of
symphysis. the iliac crest. Inferior fibres, from the third and fourth sacral segments,
ascend to the posterior superior iliac spine and posterior end of the
Movements Angulation, rotation and displacement are possible but internal lip of the iliac crest; they may form a separate long posterior


slight, and are likely during movement at the sacroiliac and hip joints. sacroiliac ligament. This ligament is continuous laterally with part of
The movements at the pubic symphysis range between 0.1 and 2 mm the sacrotuberous ligament and medially with the posterior lamina of
and are higher along the vertical axis than along the sagittal and trans- the thoracolumbar fascia.
verse axes (Walheim et al 1984). Excessive movement may occur fol-
lowing an injury. Some separation occurs late in gestation and during Iliolumbar ligament See page 738.
childbirth; on occasion, this is considerable.
Sacrotuberous ligament The sacrotuberous ligament (see Figs 80.9,
Relations Anteriorly, the pubic symphysis is related to subcutaneous 43.68) is attached by its broad base to the posterior superior iliac spine,
tissue and skin. Because of the obliquity of the joint, the proximal ends the posterior sacroiliac ligaments (with which it is partly blended),
of the penile or clitoral shafts lie anterior to the lower half of the joint. lateral sacral crest, and the lateral margins of the lower sacrum and
Inferiorly, the urethra lies about 2.5 cm away in the male, and some- upper coccyx. Its oblique fibres descend laterally, converging to form a
what closer in the female, as it passes through the perineal membrane. thick, narrow band that widens again below and is attached to the
Closer to the joint, the deep dorsal vein of the penis or clitoris passes medial margin of the ischial tuberosity. It then spreads along the ischial
between the arcuate ligament and the anterior border of the perineal ramus as the falciform process, whose concave edge blends with the
membrane. Posteriorly, the upper part of the joint is separated from the fascial sheath of the internal pudendal vessels and pudendal nerve. The
inferolateral surfaces of the urinary bladder by the retropubic fat pad. lowest fibres of gluteus maximus are attached to the posterior surface
Inferiorly in the male, the prostatic venous plexus separates the prostate of the ligament; superficial fibres of the lower part of the ligament


from the lower part of the joint. The region is sometimes termed the continue into the tendon of biceps femoris. The coccygeal branches of
retropubic space (of Retzius). These relationships explain why traumatic the inferior gluteal artery, the perforating cutaneous nerve and filaments
disruption of the anterior bony pelvis may be associated with serious of the coccygeal plexus pierce the ligament.
urogenital injury.
Sacrospinous ligament The thin, triangular sacrospinous ligament
(see Fig. 80.9) extends from the ischial spine to the lateral margins of
SACROILIAC JOINT the sacrum and coccyx anterior to the sacrotuberous ligament, with
which it blends in part. Its anterior surface is in fact the coccygeus
The sacroiliac joint occurs between the sacral and iliac auricular surfaces muscle, i.e. muscle and ligament are coextensive. The sacrospinous liga-
and, in essence, is a stress-relieving joint (Bogduk 1997) (see Fig. ment is often regarded as a degenerate part of coccygeus.
80.8A). The joint consists of syndesmotic and synovial parts. Fibrous
adhesions and gradual obliteration occur in both sexes, earlier in males, Sciatic foramina The sacrotuberous and sacrospinous ligaments
and after menopause in females. Radiological evidence of obliteration convert the sciatic notches into foramina (see Fig. 80.9).
in normal subjects is occasionally seen before 50 years but is not
uncommon thereafter; in old age, the joint may be completely fibrosed Greater sciatic foramen The greater sciatic foramen is bounded
and occasionally even ossified. anterosuperiorly by the greater sciatic notch, posteriorly by the sacro-
tuberous ligament and inferiorly by the sacrospinous ligament and
Articulating surfaces The surfaces are nearly flat in infants, whereas ischial spine (see Fig. 80.9). It is partly filled by the emerging piriformis,
in adults they are irregular, often markedly so, and sometimes undu- above which the superior gluteal vessels and nerve leave the pelvis.


lant. The curvatures and irregularities, greater in males, are reciprocal; Below it, the inferior gluteal vessels and nerve, internal pudendal vessels
they restrict movements and contribute to the considerable strength of and pudendal nerve, sciatic and posterior femoral cutaneous nerves and
the joint in transmitting weight from the vertebral column to the lower the nerves to obturator internus and quadratus femoris all leave the
limbs. The sacral surface is covered by hyaline cartilage, which is thicker pelvis.


Muscles
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Lesser sciatic foramen The lesser sciatic foramen is bounded anteri- Psoas major
orly by the ischial body, superiorly by its spine and sacrospinous liga- Attachments Psoas major is a long muscle that lies on either side
ment, and posteriorly by the sacrotuberous ligament (see Fig. 80.9A). of the lumbar vertebral column and the pelvic brim (Fig. 80.22, see
It transmits the tendon of obturator internus, the nerve to obturator Fig. 62.7). Its proximal attachments are complex. They include the
internus, and the internal pudendal vessels and pudendal nerve. anterior surfaces and lower borders of the transverse processes of all the
lumbar vertebrae. There are five digitations, each from the bodies of two
Vascular supply The arterial supply of the sacroiliac joint is derived adjoining vertebrae and their intervertebral disc. The highest of these
from the iliolumbar, superior gluteal and superior lateral sacral arteries, arises from the lower margin of the body of the twelfth thoracic verte-
with corresponding venous drainage. Lymphatic drainage follows the bra, the upper margin of the body of the first lumbar vertebra and the
arteries, reaching the iliac and lumbar nodes. interposed intervertebral disc. The lowest arises from the adjacent
margins of the bodies of the fourth and fifth lumbar vertebrae and the
Innervation Nerve fibres ramify within the joint capsule and adjoin-
interposed disc. A series of tendinous arches extend across the narrow
ing ligaments, but their source is uncertain. It is thought that the joint
parts of the bodies of the lumbar vertebrae between the digitations
probably receives branches from the anterior and posterior rami of the
already described. The lumbar arteries and veins, and filaments from
first two sacral spinal nerves, and from the superior gluteal nerve, and
that there may also be contributions from the obturator nerve and the
lumbosacral trunk.
The sacroiliac joint has sometimes been implicated as the source of
pain in the lower back and buttocks. Diagnosing sacroiliac joint-
mediated pain is difficult because the presenting complaints are similar


to those seen with other causes of back pain. Patients with sacroiliac
joint-mediated pain rarely report pain above the level of L5; most local-
ize their pain to the area around the posterior superior iliac spine.
Quadratus lumborum
Factors maintaining stability The sacroiliac joint is one of the
Psoas minor
most stable joints in the body and supports the weight of the trunk.
The reciprocal irregularity of the joint surfaces allows very little move- Psoas major
ment. The tendency of the sacrum to be forced downwards by the trunk
is resisted by the extremely strong posterior ligaments, while the ilio- Iliacus
lumbar ligaments help to resist displacement of the fifth lumbar verte-
bra over the sacrum. The sacrotuberous and sacrospinous ligaments Anterior superior iliac spine
oppose upward tilting of the lower part of the sacrum when downward
thrust is applied at its upper end. Inguinal ligament
Piriformis
Movements Primary movement of the sacroiliac joint is minimal. All
Coccygeus
muscles that cross the joint act on the lumbar spine or on the hip. Such
Levator ani
movements as do occur are secondarily imposed on the joint as the
pelvis moves. Data from living subjects are technically difficult to Pubic tubercle
obtain, and those based on plain radiographs are unreliable. Studies
Tensor fasciae latae
using implanted tantalum spheres and biplanar radiography have
shown mean rotational ranges of less than 2°. Even when there is Pectineus
recordable movement, the direction of movement is irregular. Biplanar
radiography has also shown that the axes of movement of the sacroiliac Adductor longus
joint during hip movement are oblique, and that the axes differ in
flexion and extension.
Gracilis
During pregnancy, the pelvic joints and ligaments loosen under the
influence of the hormone relaxin. Movements in the joints increase.
Relaxation renders the sacroiliac locking mechanism less effective, per- Sartorius
mitting greater rotation and perhaps allowing alterations in pelvic
diameters at childbirth, although the effect is probably small. The Adductor magnus
impaired locking mechanism diverts the strain of weight-bearing to the
ligaments, with frequent sacroiliac strain after pregnancy.
Rectus femoris


Relations The sacroiliac joints have many important anterior rela-
tions. The internal and external iliac veins join to form the common
Iliotibial tract
iliac veins immediately anteriorly, separating the joints from the bifur-
cations of the common iliac arteries and, more anteriorly, the ureters.
The lumbosacral trunk and the obturator nerve cross the anterior aspect
of the joint behind the vessels. Piriformis partly attaches to the anterior Vastus lateralis
capsule, separating the joint from the upper part of the sacral plexus.
Vastus medialis
Variants Accessory sacroiliac articulations are not uncommon. They
develop behind the articular surface between the lateral sacral crest and
posterior superior iliac spine and iliac tuberosity, and are acquired
fibrocartilaginous joints resulting from the stresses of weight-bearing.
They have a joint capsule, are saddle-shaped, and may be single, double,
unilateral or bilateral (Weisl 1954).
MUSCLES
MUSCLES OF THE ILIAC REGION
Although there is no ‘iliac region’ as such, this heading conveniently
describes a group of three muscles that originate from the lumbar ver-
tebral column (psoas major and minor) and the ilium (iliacus). Psoas
major and iliacus are attached together on the femur as flexors of the
hip joint and are often considered as a functional unit, iliopsoas. Psoas
minor only reaches the pubis, and acts on the spine and sacroiliac joint. Fig. 80.22 The hip flexors and superficial muscles of the thigh.


Pelvic girdle, gluteal region and thigh
1356
9
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the sympathetic trunk, pass medial to these arches. The upper four Vascular supply The main arterial supply to psoas minor is from
lumbar intervertebral foramina bear important relations to these attach- the lumbar arteries, though there may be minor contributions from
ments of the muscle. The foramina lie anterior to the transverse proc- other vessels of the network that supplies psoas major.
esses and posterior to the attachments to vertebral bodies, intervertebral
discs and tendinous arches. Thus, the roots of the lumbar plexus enter Innervation Psoas minor is innervated by a branch from L1.
the muscle directly, the plexus is lodged within it, and its branches
emerge from its borders and surfaces. Actions Psoas minor is probably a weak flexor of the trunk.
The muscle descends along the pelvic brim, continues posterior to
the inguinal ligament and anterior to the capsule of the hip joint, and Testing Psoas minor cannot be tested clinically.
converges to a tendon that, having received on its lateral side nearly all
the fibres of iliacus, becomes attached to the lesser trochanter of the Iliacus
femur. The large subtendinous iliac bursa, which occasionally commu-
Attachments Iliacus (see Figs 80.22, 62.7) is a triangular sheet of
nicates with the cavity of the hip joint, separates the tendon from the
muscle that arises from the superior two-thirds of the concavity of the
pubis and the capsule of the joint.
iliac fossa, the inner lip of the iliac crest, the ventral sacroiliac and iliol-
The complex vertebral attachments of psoas major sometimes
umbar ligaments, and the upper surface of the lateral part of the sacrum
display minor numerical variations.
(see Fig. 43.49). In front, it reaches as far as the anterior superior and
ant erior inferior iliac spines, and receives a few fibres from the upper
Relations The upper limit of psoas major is posterior to the dia-
part of the capsule of the hip joint (iliocapsularis, p. 1377). Most of its
phragm in the lowest part of the posterior mediastinum. It may be in


fibres converge into the lateral side of the strong tendon of psoas major,
contact with the posterior extremity of the pleural sac. In the abdomen,
and the muscles then insert together into the lesser trochanter, but some
its anterolateral surface is related to the medial arcuate ligament (a
fibres are attached directly to the femur 2.5 cm below and in front of
linear, arched thickening in the psoas fascia), extraperitoneal tissue and
the lesser trochanter.
peritoneum, the kidney, psoas minor, renal vessels, ureter, testicular or
ovarian vessels and the genitofemoral nerve. Anteriorly, the right psoas
Relations In the abdomen, the anterior surface of iliacus is related to
is overlapped by the inferior vena cava and crossed by the terminal part
its fascia (which separates the muscle from extraperitoneal tissue and
of the ileum; the colon crosses the left psoas. Its posterior surface is
peritoneum), the lateral femoral cutaneous nerve, the caecum (on the
related to the transverse processes of the lumbar vertebrae and the
right) and the iliac part of the descending colon (on the left). On its
medial edge of quadratus lumborum. The lumbar plexus is embedded
posterior surface is the iliac fossa, and at its medial border, psoas major
posteriorly in the substance of psoas major. Medially, the muscle is
and the femoral nerve. In the thigh, its anterior surface is in contact
related to the bodies of the lumbar vertebrae and lumbar vessels. Along
with the fascia lata, rectus femoris, sartorius and the profunda femoris
its anteromedial margin, it is in contact with the sympathetic trunk,
artery, and its posterior surface is in contact with the capsule of the hip
aortic lymph nodes and, along the pelvic brim, with the external iliac
joint, from which it is partially separated by a bursa it shares with psoas
artery. This margin is covered by the inferior vena cava on the right side,
major.
and lies posterior and lateral to the abdominal aorta on the left side.
In the thigh, iliopsoas is related anteriorly to the fascia lata and the


Vascular supply Iliacus is supplied by the same arterial network as
femoral artery, and posteriorly to the capsule of the hip joint, from
psoas major, and there is mutual overlap of the arterial territories of
which it is separated by a bursa. At its medial border, it is related to
each muscle. The main supply is from the iliac branches of the iliolum-
pectineus and the medial circumflex femoral artery, and to the femoral
bar artery, with contributions from the deep circumflex iliac and obtur-
vein, which may overlap it slightly. At its lateral border, it is related to
ator arteries, and branches of the femoral artery.
the femoral nerve and iliacus. The femoral nerve descends at first
through the fibres of psoas major, and then in the furrow between it
Innervation Iliacus is innervated by branches of the femoral nerve,
and iliacus.
L2 and 3.
Branches of the lumbar plexus diverge from the abdominal part of
psoas major. Emerging from the lateral border, from above downwards,
Actions Psoas major, acting from above together with iliacus, flexes
are the iliohypogastric, ilioinguinal and lateral femoral cutaneous and
the thigh on the pelvis. Electromyographic studies do not support the
femoral nerves. Emerging from the anterolateral surface is the genito-
common view that psoas major acts as a medial rotator of the hip joint,
femoral nerve. The obturator and accessory obturator nerves (when
but activity has been described in lateral rotation, particularly in the
present) and the upper root of the lumbosacral trunk all emerge from
young. When psoas major and iliacus of both sides act from below, they
the medial border.
contract powerfully to bend the trunk and pelvis forwards against resist-
ance, as in raising the trunk from the recumbent to the sitting posture
Vascular supply Psoas major is supplied by a rich network of arteries
when undertaking a ‘sit-up’ exercise.
derived from the lumbar, iliolumbar, obturator, external iliac and
Electromyography does not support the commonly held belief that
femoral arteries. In general terms, the upper part of the muscle is sup-


unilateral action of psoas major causes lateral and forward flexion of
plied by the lumbar arteries, the mid part by the anterior branch of the
the trunk to that side (Joseph 1975).
iliolumbar artery (the main artery to the muscle) with contributions
In symmetrical upright stance, iliopsoas has some action from below
from the deep circumflex and external iliac arteries, and the distal part
to maintain the vertebral column upright. Psoas major is active in bal-
by the femoral artery and its branches. The psoas sheath has an arterial
ancing the trunk while sitting.
supply independent from that of the muscle, though the same vessels
contribute.
Testing Both psoas and iliacus may be the sites of pathological col-
lections of fluid. An abscess (typically tuberculous) of vertebral origin
Innervation Psoas major is innervated by the ventral rami of the
may track down through psoas and present as a mass in the thigh.
lumbar spinal nerves, mainly L1 and 2 with some contribution from
Haematoma or infection within the iliacus fascia may present as a mass
L3.
or as a flexion deformity of the hip.
Iliopsoas may be tested clinically by actively flexing the hip against
Actions Psoas major acts together with iliacus; the combination is
resistance, in the supine position with the hip and knee flexed.
referred to as iliopsoas. See below (‘Iliacus’).
Testing See below (after ‘Iliacus’).
MUSCLES OF THE GLUTEAL REGION
Psoas minor
Attachments Psoas minor (see Fig. 80.22) is sometimes absent. Tensor fasciae latae
When present, it lies anterior to psoas major, entirely within the Attachments Tensor fasciae latae (see Fig. 80.22) arises from the
abdomen. It arises from the sides of the bodies of the twelfth thoracic anterior 5 cm of the outer lip of the iliac crest, from the lateral surface
and first lumbar vertebrae, and from the intervertebral disc between of the anterior superior iliac spine and part of the border of the notch


them. It ends in a long, flat tendon that is attached to the pecten pubis, below it, between gluteus medius and sartorius, and from the deep
iliopubic ramus and, laterally, to the iliac fascia. surface of the fascia lata. Proximal attachments may extend to the
aponeurotic fascia superficial to gluteus medius. It descends between,
Relations Psoas minor lies on psoas major, and its proximal anterior and is attached to, the two layers of the iliotibial tract of the fascia lata
relations are those of the anterior or anteromedial surface of that muscle. and usually ends approximately one-third of the way down the thigh,


Muscles
1357
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although it may occasionally extend as far as the lateral femoral
condyle. Gluteal fascia (cut)
Vascular supply The muscle itself is supplied mainly by a large
ascending branch of the lateral circumflex femoral artery. The tensor
fasciae latae musculocutaneous flap is raised on this pedicle. The supe- Gluteus medius
rior part of the muscle receives branches from the superior gluteal artery.
The fascia surrounding the muscle is supplied on its superficial aspect
by the superficial circumflex iliac artery and on its deep surface by the
lateral circumflex femoral artery.
Gluteus maximus
Innervation Tensor fasciae latae is innervated by the superior gluteal
nerve, L4, 5 and S1.
Actions Tensor fasciae latae, acting through the iliotibial tract, extends
the knee with lateral rotation of the leg; it may also assist in abduction Coccyx
and medial rotation of the thigh, though its role as an abductor is
debatable. The muscle helps to maintain upright posture while mini-
mizing energy expenditure on muscle activity: when the subject is
Greater trochanter
standing it acts from below to steady the pelvis on the head of the femur
and, through the iliotibial tract, to steady the condyles of the femur on
the tibial condyles while the knee extensors are relaxed. The muscle aids
gluteus medius in postural abduction at the hip. Postural control is its
main function.
In the last 20° or so of extension, the pull of the iliotibial tract is
Adductor magnus
anterior to the flexion axis of the knee and so the tensor fasciae latae is
a weak extensor. Flexion of greater than 20° leads to the iliotibial tract
passing posterior to the axis of flexion so that the muscle becomes a Biceps femoris
weak flexor.
Testing When the thigh is flexed against gravity and the knee is Semitendinosus
extended, an angular depression appears immediately below the ant-
erior superior iliac spine; its lateral boundary is tensor fasciae latae. If
the thigh is then abducted against resistance, the muscle can be felt and Fascia lata
sometimes seen.
Gluteus maximus Gracilis


Attachments Gluteus maximus (Fig. 80.23) is the largest and most
superficial muscle in the gluteal region. It is a broad, thick, quadrilateral
mass, which, with its overlying adipose fascia, forms the familiar promi-
nence of the buttock. Gluteus maximus is thicker and more extensive
in humans than in any non-human primate, features that presumably
Fig. 80.23 Gluteus maximus, posterior view with the posterior thigh
correlate with the evolutionary transition to bipedality and a perma-
muscles seen through the overlying fascia lata.
nently upright posture. The muscle has a coarse fascicular architecture,
with large bundles of fibres separated by fibrous septa. It arises from
the posterior gluteal line of the ilium and the rough area of bone,
including the crest, immediately above and behind it; from the aponeu- fold (the posterior flexure line of the hip joint), which marks the upper
rosis of erector spinae; the dorsal surface of the lower part of the sacrum limit of the back of the thigh on the surface.
and the side of the coccyx; the sacrotuberous ligament; and the fascia
(gluteal aponeurosis) that covers gluteus medius. There may be addi- Vascular supply The dominant vascular pedicle is usually that of
tional slips from the lumbar aponeurosis or ischial tuberosity. The the inferior gluteal artery, which supplies approximately two-thirds of
muscle may also be bilaminar. The fibres descend laterally; the upper the muscle. The remainder is supplied mainly by the superior gluteal
part of the muscle, together with the superficial fibres of the lower part, artery, though this may sometimes be the dominant vessel. The lateral
ends in a thick tendinous lamina that passes lateral to the greater tro- and distal borders of the muscle receive a supply from the first perfora-
chanter and is attached to the iliotibial tract of the fascia lata. The tor given off from the profunda femoris artery and from the medial
deeper fibres of the lower part of the muscle are attached to the gluteal circumflex femoral artery. Minor branches may be derived from the


tuberosity between vastus lateralis and adductor magnus. lateral circumflex femoral, lateral sacral and internal pudendal
arteries.
Relations A thin fascia separates the superficial surface of gluteus Gluteus maximus musculocutaneous flaps may be based on either
maximus from the overlying thick, adipose subcutaneous tissue. The of the gluteal vessels or on the first perforator given off from the pro-
deep surface of the muscle is related to the ilium, sacrum, coccyx, sac- funda femoris artery, depending on the site and size of the defect requir-
rotuberous ligament, part of gluteus medius, piriformis, the gemelli, ing coverage.
obturator internus, quadratus femoris, the ischial tuberosity, greater
trochanter, and the attachments of biceps femoris, semitendinosus, Innervation Gluteus maximus is innervated by the inferior gluteal
semimembranosus and adductor magnus to the ischial tuberosity. nerve, L5, S1 and S2.
Three bursae lie deep to gluteus maximus: trochanteric, over the greater
trochanter; gluteofemoral, between the tendon of gluteus maximus and Actions Acting from the pelvis, gluteus maximus can extend the flexed
that of vastus lateralis; and ischiofemoral, over the gluteal tuberosity, thigh and bring it into line with the trunk. Acting from its distal attach-
which is less commonly present. ment, it may prevent the forward momentum of the trunk from produc-
The superficial division of the superior gluteal artery reaches the ing flexion at the supporting hip during bipedal gait. The muscle is
deep surface of the muscle between piriformis and gluteus medius. The inactive during standing, when swaying forwards at the ankle joints, or
inferior gluteal and internal pudendal vessels, the sciatic, pudendal and when bending forwards at the hip joints to touch the toes. However, it
posterior femoral cutaneous nerves, muscular branches from the sacral acts with the hamstrings in raising the trunk after stooping, by rotating


femoral cutaneous nerves, and muscular branches from the sacral the pelvis backwards on the head of the femur. It is intermittently active
plexus all leave the pelvis below piriformis. The first perforating artery in the walking cycle and in climbing stairs, and continuously active in
and the terminal branches of the medial circumflex femoral artery are strong lateral rotation of the thigh. Its upper fibres are active in powerful
also deep to the lower part of gluteus maximus. Its upper border is thin abduction of the thigh. It is a tensor of the fascia lata, and through the
and overlies gluteus medius. Its prominent lower border is free and iliotibial tract it stabilizes the femur on the tibia when the extensor
slopes downwards and laterally. It is crossed by the horizontal gluteal muscles of the knee are relaxed.


Pelvic girdle, gluteal region and thigh
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Vascular supply The main supply to gluteus medius is from the deep
branch of the superior gluteal artery (Fig. 80.25A). The distal part of
A
the muscle is supplied by the trochanteric anastomosis.
Innervation Gluteus medius is innervated by the superior gluteal
nerve, L4, 5 and S1.
Gluteus medius
Actions These are considered below with gluteus minimus.
Testing This is considered below with gluteus minimus.
Gluteus minimus
Attachments Gluteus minimus lies deep to gluteus medius (see
Fig. 80.24B). The fan-shaped muscle arises from the outer surface of the
ilium between the anterior and inferior gluteal lines and, behind, from
the margin of the greater sciatic notch. The fibres converge below to the
deep surface of an aponeurosis that ends in a tendon attached to an
anterolateral ridge on the greater trochanter and contributes an expan-
sion to the capsule of the hip joint.
The muscle may divide into anterior and posterior parts. Separate
slips may pass to piriformis, gemellus superior or vastus lateralis.
Relations Branches of the deep division of the superior gluteal artery
and nerve run on the superficial surface of the muscle. The reflected
tendon of rectus femoris and the capsule of the hip joint are deep to
gluteus minimus. A bursa (trochanteric bursa of gluteus minimus) sepa-
B rates the tendon from the medial part of the anterior surface of the
greater trochanter.
Vascular supply Gluteus minimus is supplied from both its surfaces,
from the main trunk and the deep branch of the superior gluteal artery,
with a contribution at its femoral attachment from the trochanteric
anastomosis (see Fig. 80.25).
Gluteus minimus
Innervation Gluteus minimus is innervated by the superior gluteal
nerve, L4, 5 and S1.
Piriformis
Gemellus superior Actions of gluteus medius and minimus
Both gluteus medius and minimus, acting from the pelvis, abduct the


thigh, and their anterior fibres rotate it medially. Acting from the femur,
Gemellus inferior
they play an essential part in maintaining the trunk upright when the
Quadratus femoris
foot of the opposite side is raised from the ground in walking and
Obturator internus running. In this phase, the body weight tends to make the pelvis sag
downwards on the unsupported side. This is counteracted by the gluteus
medius and minimus of the supporting side, which, acting from below,
exert such powerful traction on the hip bone that the pelvis is actually
raised a little on the unsupported side. In symmetrical standing with
the feet somewhat separated, the abductor muscles are usually ‘silent’
on electromyography, but with the feet placed parallel and close
together they are active.
Fig. 80.24 A, Gluteus medius, posterior view. B, Gluteus minimus and
short lateral rotators of the hip, posterior view.
Testing The supportive effect of the glutei (medius and minimus) on
the pelvis when the contralateral foot is raised depends on the following
conditions. The two muscles, and their innervation, must be function-
ing normally. The components of the hip joint, which forms the
Testing Gluteus maximus may be tested by extension of the hip fulcrum, must be in their usual relation. The neck of the femur must
against resistance, in the supine or prone position. be intact, with its normal angulation to the shaft.
When any one of these conditions is not fulfilled, e.g. in paralysis
Gluteus medius
of the glutei, developmental dysplasia of the hip or coxa vara, the sup-
Attachments Gluteus medius is a broad, thick muscle (see Fig. 80.23; porting mechanism is upset and the pelvis sinks on the unsupported
Fig. 80.24A). It arises from the outer surface of the ilium between the side when the patient tries to stand on the affected limb. This is known
iliac crest and posterior gluteal line above, and the anterior gluteal line clinically as Trendelenburg’s sign. Individuals with paralysis of gluteus
below, and also from the strong fascia superficial to its upper part. The medius and minimus have a characteristic lurching gait. Provided that


fibres converge to a flat tendon that attaches to a ridge that these two muscles are intact, paralysis of other muscles acting on the
slants downwards and forwards on the lateral surface of the greater hip joint produces remarkably little deficit in walking, or even in
trochanter. running.
A deep slip of the muscle may be attached to the upper border of Gluteus medius and minimus may be tested together by medial
the trochanter. The posterior edge of gluteus medius sometimes blends rotation of the thigh against resistance, in the supine position with hip
with piriformis. and knee flexed. Both muscles may be tested together with tensor
fasciae latae by abduction of the lower limb against resistance, in the
Relations The posterior third of gluteus medius is covered by gluteus supine position with the knee extended.
maximus but it is superficial in its anterior two-thirds, where a strong
Piriformis
layer of deep fascia covers it. Its deep surface is related to gluteus
minimus. Branches of the deep divisions of the superior gluteal nerve Attachments Piriformis (see Figs 80.24B, 80.25A) occupies a central
and artery run between the medius and minimus muscles, and are position in the buttock, where it lies in the same plane as gluteus
vulnerable during anterolateral and lateral approaches to the hip medius. It arises from the anterior surface of the sacrum by three digit-
that involve splitting gluteus medius. Where the tendon glides on the ations, which are attached to the portions of bone between the pelvic
anterosuperior part of the lateral surface of the trochanter, a bursa sacral foramina, and to the grooves leading from the foramina (see
(trochanteric bursa of gluteus medius) separates it from the bone. Fig. 43.49). It also arises from the gluteal surface of the ilium near the


Muscles
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A B
Superior gluteal artery
Psoas major and Iliacus
Inferior gluteal artery
Piriformis Sartorius
Lateral circumflex
femoral artery
Profunda femoris artery
Lateral circumflex femoral artery
Cruciate anastomosis Rectus femoris
Medial circumflex
femoral artery
Medial circumflex femoral artery Pectineus
Adductor longus
First perforating artery
Adductor brevis
Second perforating artery First, second and third
perforating arteries
Third perforating artery
Terminal segment of profunda
femoris artery
Adductor magnus
Vastus intermedius
Terminal segment of profunda
femoris artery
Adductor magnus
Vastus lateralis
Adductor hiatus
Vastus medialis, cut
Tendon of quadriceps femoris
Popliteal artery
Gracilis
Fig. 80.25 The arteries and muscles of the left gluteal and femoral regions. A, Posterior aspect. B, Anterior aspect. (With permission from Drake RL, Vogl
AW, Mitchell A (eds), Gray’s Anatomy for Students, 2nd ed, Elsevier, Churchill Livingstone. Copyright 2010.)
posterior inferior iliac spine, from the capsule of the adjacent sacroiliac the inferior gluteal artery (see Fig. 80.25A). In the pelvis, the main
joint, and sometimes from the upper part of the pelvic surface of the supply is from the lateral sacral artery, with contributions from both
sacrotuberous ligament. The muscle passes out of the pelvis through gluteal vessels.
the greater sciatic foramen, which it substantially fills. Here it consti-
tutes an important surgical landmark in the identification of structures Innervation Piriformis is innervated by branches from S1 and 2
that emerge above and below it. It inserts into the medial side of the (sometimes only from S2). It may also contain fibres from L5.
upper border of the greater trochanter of the femur via a rounded
tendon that lies behind and above, but is often partially blended with, Actions Piriformis rotates the extended thigh laterally, but abducts the
the common tendon of obturator internus and the gemelli. The muscle flexed thigh.


itself may be fused with gluteus medius.
Testing Clinically, it is not possible to test piriformis alone; however,
Relations Within the pelvis, the anterior surface of piriformis is for suspected injury to piriformis the best provocative test is to ask the
related to the rectum (especially on the left), the sacral plexus of nerves seated subject to abduct the thighs. Buttock pain suggests piriformis
and branches of the internal iliac vessels. The posterior surface lies injury.
against the sacrum. Outside the pelvis, its anterior surface is in contact
Obturator internus
with the posterior surface of the ischium and capsule of the hip joint,
and its posterior surface with gluteus maximus. Its upper border is in Attachments Obturator internus (see Figs 80.24B, 80.27) is situated
contact with gluteus medius and the superior gluteal vessels and nerve, partly within the true pelvis and partly posterior to the hip joint. It
its lower border with coccygeus and gemellus superior. The inferior arises from the internal surface of the anterolateral wall of the lesser
gluteal and internal pudendal vessels, the sciatic, posterior femoral pelvic cavity. Its attachments, which almost surround the obturator
cutaneous and pudendal nerves, and muscular branches from the sacral foramen, are to the inferior ramus of the pubis, the ischial ramus, and
plexus appear in the buttock in the interval between piriformis and the pelvic surface of the hip bone below and behind the pelvic brim,
gemellus superior. The relationship between piriformis and the sciatic to the upper part of the greater sciatic foramen above and behind, to
nerve is variable. The undivided nerve may emerge above the muscle or the obturator foramen below and in front. It also arises from the
through the muscle. The major divisions of the nerve may lie either side medial part of the pelvic surface of the obturator membrane, from the
of the muscle, or (the most common variant) one division passes tendinous arch that completes the obturator canal, and, to a small
between the heads of a divided muscle and one division either above extent, from the obturator fascia that covers the muscle. The fibres
or below. converge towards the lesser sciatic foramen and end in four or five


Piriformis can occasionally cause entrapment of the sciatic nerve in tendinous bands on the deep surface of the muscle. These bands make
the buttock, giving rise to the so-called ‘piriformis syndrome’. a lateral right-angled turn around the grooved surface of the ischium
between its spine and tuberosity. The grooved surface is covered with a
Vascular supply In the buttock, piriformis is supplied mainly from smooth layer of hyaline cartilage and is separated from the tendon by
the superior gluteal artery, with contributions from the gemellar a bursa; ridges on the surface correspond to furrows between the tendi-
branches of the internal pudendal. There may be a separate branch from nous bands. These bands leave the pelvis through the lesser sciatic


Pelvic girdle, gluteal region and thigh
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foramen and unite to form a single flattened tendon that passes hori- Relations A bursa, which communicates with the hip joint, may be
zontally across the capsule of the hip joint. The gemelli fuse with this interposed between the tendon and the hip joint capsule and femoral
tendon before it inserts on to an anterior impression on the medial neck. The obturator vessels lie between the muscle and the obturator
surface of the greater trochanter anterosuperior to the trochanteric membrane. The anterior branch of the obturator nerve reaches the
fossa. A long, narrow bursa is usually interposed between the tendon thigh by passing in front of the muscle, and the posterior branch by
and the capsule of the hip joint, and occasionally communicates with piercing it.
the bursa between the tendon and the ischium.
Vascular supply Obturator externus receives a variable pattern of
Relations Within the pelvis, the anterolateral surface of the muscle is supply from the obturator and medial circumflex femoral arteries.
in contact with the obturator membrane and inner surface of the lateral
wall of the pelvis. Its posteromedial surface is related to the obturator Innervation Obturator externus is innervated by the posterior branch
fascia, the origin of levator ani, and the sheath that surrounds the of the obturator nerve, L3 and 4.
internal pudendal vessels and pudendal nerve, and forms the lateral
wall of the ischio-anal fossa. Outside the pelvis, the muscle is covered Actions It has been suggested that the short muscles around the hip
by gluteus maximus, is crossed posteriorly by the sciatic nerve and joint (pectineus, piriformis, obturator externus and internus, the gemelli
passes behind the hip joint. As the tendon of obturator internus emerges and quadratus femoris) are more important as postural muscles than
from the lesser sciatic foramen, it is overlapped both above and below as prime movers, acting as adjustable ligaments to maintain the stability
by the two gemelli, which form a muscular canal for it. Near its termi- and integrity of the hip. However, these muscles are largely inaccessible


nation, the gemelli pass anterior to the tendon and form a groove in to direct observation, and, because of the hazards presented by their
which it lies. close relationship to important neurovascular structures, there is a lack
of electromyographic data in humans. In both bipedal walking and
Vascular supply The main arterial supply of the extrapelvic part of vertical climbing, obturator externus is recruited during the early part
obturator internus is from the gemellar branches of the internal puden- of the swing phase; in climbing it effects lateral rotation of the thigh,
dal artery. Intrapelvic and extrapelvic parts are supplied by the branches and in walking it probably counteracts the tendency to medial rotation
of the obturator artery. produced by the anterior adductor muscles at this stage of the cycle.
Obturator internus differs from obturator externus in its pattern of use
Innervation Obturator internus is innervated by the nerve to obtura- but its role in bipedal walking remains unclear. Its attachments suggest
tor internus, L5 and S1.
Actions See below actions of obturator externus.
Obturator externus
Attachments Obturator externus (Figs 80.26–80.29; see Fig. 80.16)
is a flat, triangular muscle covering the external surface of the anterior
Gluteus medius
pelvic wall. It arises from the anteromedial two-thirds of the external
surface of the obturator membrane, and from the adjacent bone of the
pubic and ischial rami, extending for a short distance on to their pelvic
surfaces between the margin of the obturator foramen and the obtura- Gluteus minimus Gluteus maximus
tor membrane. The whole muscle, and the tendon into which its fibres
converge, spiral backwards, laterally and upwards, and thus cross the Piriformis
inferior aspect and then the back of the neck of the femur and lower
part of the capsule of the hip joint to end in the trochanteric fossa of Gemellus superior
the femur.
Obturator internus
Gemellus inferior
Quadratus femoris
Trochanteric bursa
Gluteus maximus
Adductor magnus
Semitendinosus
Biceps femoris, short head
Biceps femoris, long head Semimembranosus


Popliteal artery
Gastrocnemius
Obturator externus
Fig. 80.27 The posterior thigh and gluteal muscles with gluteus maximus
Fig. 80.26 Obturator externus, anterior aspect. (Adapted from Drake RL, and medius partially removed. (With permission from Waschke J, Paulsen
Vogl AW, Mitchell A (eds), Gray’s Anatomy for Students, 2nd ed, Elsevier, F (eds), Sobotta Atlas of Human Anatomy, 15th ed, Elsevier, Urban &
Churchill Livingstone. Copyright 2010.) Fischer. Copyright 2013.)


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that it, like the gemelli, is a lateral rotator of the extended thigh and an Anterior compartment
abductor of the flexed thigh. These actions may be used to antagonize
unwanted components of movement produced by the primary locomo-
The muscles of the anterior compartment (see Figs 80.2, 80.22) include
tor muscles.
sartorius and rectus femoris, which can act at both the hip and knee
joints, and vasti medialis, lateralis and intermedius, which act
Testing The short rotators cannot be tested individually, but lateral
only at the knee. Articularis genus completes the group: it retracts the
rotation of the extended hip and abduction of the flexed hip against
synovial capsule of the knee joint. Rectus femoris and the vasti extend
resistance tests them as a group.
the knee joint through a common tendon and hence are collectively
termed quadriceps femoris. Adductor longus and pectineus are some-
Gemellus inferior and gemellus superior
times considered to be part of both the anterior and the adductor
Attachments Gemellus inferior arises from the upper part of the
compartments.
lateral surface of the ischial tuberosity, immediately below the groove
for the tendon of obturator internus (Fig. 80.27). It blends with the Sartorius
lower border of this tendon, and inserts with it into the medial surface Attachments Sartorius is a narrow strap muscle and is the longest
of the greater trochanter. muscle in the body (see Fig. 80.31). It arises by tendinous fibres from
Gemellus superior, the smaller of the two gemelli, arises from the the anterior superior iliac spine and the upper half of the notch below
dorsal surface of the ischial spine, blends with the upper border of the it. It crosses the thigh obliquely over to the medial side and then
tendon of obturator internus, and inserts with it into the medial surface descends more vertically to the medial side of the knee. The muscle
of the greater trochanter. It is sometimes absent. fibres terminate at this point and a thin, flattened tendon curves


The two gemelli can be regarded as accessory to obturator internus obliquely forwards and expands into a broad aponeurosis. The aponeu-
(see Fig. 80.24B). rosis is attached to the proximal part of the medial surface of the tibia
in front of gracilis and semitendinosus, together forming the so-called
Relations The relations of the gemelli are as described for the extrapel- pes anserinus (Fig. 80.28). A slip from its upper margin blends with
vic part of obturator internus. the capsule of the knee joint, and another from its lower margin merges
with the superficial layer of the deep fascia on the medial side of the
Vascular supply Gemellus superior is supplied by the internal leg. This sheet of tissue passes inferiorly to lie superficial to and over
pudendal artery and its gemellar branches; by the inferior gluteal artery; the distal insertions of gracilis and semitendinosus. It has to be split by
and sometimes also by the superior gluteal artery. Gemellus inferior is sharp dissection to reveal these two tendons if they need to be har-
supplied mainly by the medial circumflex femoral artery. vested, e.g. in cruciate ligament surgery.
In some cases, sartorius is absent, while in others, the muscle may
Innervation Gemellus superior is innervated by the nerve to obturator possess an extra head; when the latter occurs, the extra head is attached
internus, L5, S1 and S2. Gemellus inferior is innervated by the nerve to to the pectineal line or to the femoral sheath. Variations in the distal
quadratus femoris, L4, L5 and S1. attachment of sartorius, in the vicinity of the knee, have been described.
Actions The gemelli rotate the extended thigh laterally and abduct the Relations The relations of sartorius are described in the femoral tri-
flexed thigh. angle (see below).
Testing See testing of obturator externus above. Vascular supply The main arterial supply to sartorius is derived from
multiple branches of the femoral system and enters the medial half of
Quadratus femoris
the muscle from its deep surface. Vessels supplying the proximal third


Attachments Quadratus femoris (see Fig. 80.24B) is a flat, quadri- of sartorius may arise from the femoral artery, the profunda femoris
lateral muscle lying between gemellus inferior and the upper margin of artery, the ‘artery of the quadriceps’ or the lateral circumflex femoral
adductor magnus, from which it is separated by the transverse branch artery. There may be an additional proximal supply from the superficial
of the medial circumflex femoral artery. It arises from the upper part of circumflex iliac artery. Those vessels supplying the middle third of the
the external aspect of the ischial tuberosity and inserts on to a small
tubercle a little above the middle of the trochanteric crest of the femur
and into the bone for a short distance below. It may be absent.
Relations The muscle passes behind the hip joint and the neck of the
femur, separated from them by the tendon of obturator externus and
the ascending branch of the medial circumflex femoral artery (which
may cause troublesome bleeding if injured during the posterior Sartorius
approach to the hip). The sciatic nerve crosses the muscle posteriorly.
Gracilis Vastus
A bursa is often present between the muscle and the lesser trochanter. medialis
Tendon of adductor
Vascular supply Branches pass to the superficial surface of the magnus Tendon of
muscle from the inferior gluteal artery and from the medial circumflex Tendon of semitendinosus quadriceps
femoral artery, which also supplies the deep surface. Medial epicondyle of femur femoris
Tendon of semimembranosus
Innervation Quadratus femoris is innervated by the nerve to quadra-
tus femoris, L5 and S1. Tibial collateral ligament Patella
Semimembranosus
Actions Quadratus femoris produces lateral rotation of the thigh. bursa
Anserine bursa Medial patellar
retinaculum
Testing See testing of obturator externus.
Tendon of
semitendinosus Patellar ligament
MUSCLES OF THE THIGH Tendon of
gracilis Tendon of sartorius
The presence and position of the femoral neck cause the femoral shaft
to lie obliquely; consequently, the anterior (extensor) muscle group,


quadriceps femoris, runs obliquely distally and medially and so applies Gastrocnemius Tibial tuberosity
a pull to the patella that is both laterally and proximally directed. The
adductor muscles occupy the region between quadriceps femoris and
the medial margin of the thigh. They are attached distally to the post- Soleus
erior surface of the femur and lie more posteriorly than quadriceps
femoris. The posterior muscle group, the hamstrings, lie behind the
adductors. The attachments of these muscles determine the nature and
direction of displacement of femoral shaft fractures. Fig. 80.28 The distal attachment of muscles of the thigh, medial aspect.


Pelvic girdle, gluteal region and thigh
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muscle arise from the femoral artery. The distal vessels arise from the into the thick, flat tendon by which it is attached to the base of the
femoral artery within the adductor canal and from the descending patella. This constitutes the superficial central part of the quadriceps
genicular artery. femoris tendon. A third head of rectus femoris may exist; it attaches
deeply to the iliofemoral ligament and superficially to the tendon of
Innervation Sartorius is innervated by the femoral nerve, L2 and 3. gluteus minimus as it attaches on to the femur (Tubbs et al 2006).
Rectus femoris may also arise from the anterior superior iliac spine, and
Actions Sartorius assists in flexing the leg, and the thigh on the pelvis, its reflected head may be absent.
particularly when these two movements are combined. It also helps to
abduct the thigh and to rotate it laterally. Together with inversion of Relations Proximally, the muscle is covered by tensor fasciae latae,
the foot, these movements bring the sole of the foot into direct view. iliacus and sartorius. The reflected head lies beneath gluteus minimus.
The fact that sartorius represents only 1% of the physiological cross- The capsule of the hip joint, vastus intermedius, the anterior borders of
sectional area of all muscles that cross the hip or knee joint would vasti lateralis and medius, the lateral circumflex femoral artery and
appear to suggest that its role in walking is a minor one. In a subject some branches of the femoral nerve all lie deep to rectus femoris.
ascending steps, electromyographic activity of sartorius increases during
lateral rotation of the thigh at the end of the swing phase immediately Vascular supply There are two main vascular pedicles: a superior
preceding heel strike, which presumably decelerates the limb. Sartorius and an inferior. The superior enters rectus femoris at the junction of
may therefore have a significant involvement in climbing. its upper and middle thirds, and arises from the ‘artery of the quadri-
ceps’. The inferior and larger branch arises from the ‘artery of the quad-


Testing When it contracts against gravity, as it usually does, sartorius riceps’ at about mid-thigh level and enters the muscle a few centimetres
can be both seen and felt in the living subject. more distally. There are additional contributions from the lateral cir-
cumflex femoral artery and, less often, from the superficial circumflex
Femoral triangle
iliac artery.
The femoral triangle is a depressed, intermuscular space in the antero-
medial aspect of the proximal thigh, lying immediately distal to the vastus medialis and vastus medialis obliquus
inguinal ligament. The latter constitutes the base of the femoral trian- Attachments Vastus medialis arises from the lower part of the inter-
gle’s inverted triangular outline. Its lateral boundary is the medial trochanteric line, spiral line, medial lip of the linea aspera, proximal
margin of sartorius. Its medial boundary is the medial margin of adduc- part of the medial supracondylar line, the tendons of adductor longus
tor longus. Its distal extremity, the apex, is where sartorius overlaps and magnus, and the medial intermuscular septum. Its fibres pass
adductor longus (see Fig. 80.31). Its floor is provided laterally by iliacus downwards and forwards at an average angle of 15° to the long axis of
and psoas major, and medially by pectineus and adductor longus. Its the femur, most of them into an aponeurosis on the deep surface of the
roof is the overlying fascia lata. The femoral vessels, passing from mid- muscle that is attached to the medial border of the patella and to the
base to apex, are in the deepest part of the triangle. Lying lateral to the quadriceps femoris tendon. An expansion from this aponeurosis re-
artery and outside the femoral sheath is the femoral nerve, which, on inforces the capsule of the knee joint and is attached below to the
entering the femoral triangle divides into multiple branches. The trian- medial condyle of the tibia.
gle also contains fat and lymph nodes. The lowest fibres are nearly horizontal and form a bulge in the living
subject, medial to the upper half of the patella. Some authors distin-
Quadriceps femoris


guish this part of the muscle as the vastus medialis obliquus, with fibres
Quadriceps femoris (see Figs 80.2, 80.22, 80.31), the great extensor that originate largely from the tendon of adductor magnus and insert
muscle of the leg, covers almost all of the front and sides of the femur. into the medial border of the patella. It plays an important role in the
It can be divided into four parts, each named individually. One, rectus function of patellofemoral joint.
femoris, arises from the ilium and travels straight down the middle of
the thigh, its shape and path determining its name. The other three arise Relations Vastus medialis is partly covered by rectus femoris and
from the shaft of the femur and surround it (apart from the linea sartorius. In the central part of the thigh it forms the lateral wall of the
aspera) from the trochanters to the condyles: vastus lateralis is lateral adductor (Hunter’s) canal.
to the femur, vastus medialis is medial to it, and vastus intermedius lies
anterior to the femur. Rectus femoris crosses both hip and knee joints, Vascular supply Vastus medialis is supplied by three branches of the
while the three vasti only cross the knee joint. femoral artery. The superior and middle branches arise, sometimes from
The tendons of the four components of quadriceps femoris unite a common trunk, proximal to the adductor canal, while the inferior
in the lower part of the thigh to form a single strong tendon attached arises within the canal. There may also be minor branches from the
to the base of the patella, and some fibres continue over it to blend profunda femoris artery and descending genicular arteries.
with the patellar ligament. The patella is a sesamoid bone in the quad-
riceps femoris tendon, and the patellar ligament, which extends from vastus lateralis
the patellar apex to the tibial tuberosity, is the continuation of the main Attachments Vastus lateralis is the largest component of quadriceps
tendon. The medial and lateral patellar retinacula are expansions from femoris. It arises by a broad aponeurosis from the upper part of the


its borders. The suprapatellar bursa (a synovial extension of the knee intertrochanteric line, the anterior and inferior borders of the greater
joint) lies between the femur and the suprapatellar part of the quadri- trochanter, the lateral lip of the gluteal tuberosity, and the proximal half
ceps femoris tendon. The deep infrapatellar bursa lies between the of the lateral lip of the linea aspera. This aponeurosis covers the proxi-
patellar ligament and the proximal end of the tibia. mal three-quarters of the muscle; many additional fibres arise from its
The arterial supply to the quadriceps femoris has been traditionally deep surface. A few fibres also arise from the tendon of gluteus maximus
ascribed to a single branch of either the profunda femoris artery or the and the lateral intermuscular septum between vastus lateralis and the
lateral circumflex femoral artery, the ‘artery of the quadriceps’. This short head of biceps femoris. The muscular mass thus formed is attached
vessel, which may be large, occasionally arises directly from the femoral to a strong aponeurosis on the deep surface of the lower part of the
artery. However, according to Taylor and Razaboni (1994), this artery muscle. This narrows to a flat tendon, which is attached to the base and
does not supply all four components of quadriceps femoris; vastus lateral border of the patella and blends into the compound quadriceps
medialis is supplied directly from the femoral artery. The supply of the femoris tendon. It contributes an expansion to the capsule of the knee
individual muscle components is described below; their sheaths may joint that descends to the lateral condyle of the tibia and blends with
have an additional and variable supply. the iliotibial tract.
Quadriceps femoris as a group shows little anatomical variation.
Relations Vastus lateralis is covered laterally by the fascia lata and the
rectus femoris aponeurotic insertions of tensor fasciae latae and gluteus maximus. It
Attachments Rectus femoris is fusiform. Its superficial fibres are is separated from vastus intermedius by branches of the femoral nerve


bipennate, the deep fibres parallel. It has a double origin on the ilium: and the lateral circumflex femoral artery. Posteriorly, it is separated from
a straight tendon arises from the anterior inferior iliac spine, and a biceps femoris by the lateral intermuscular septum.
thinner, flatter reflected tendon from a groove above the acetabulum
and from the fibrous capsule of the hip joint. The two unite at an acute Vascular supply There are three main arteries of supply: the superior
angle and spread into an aponeurosis that is prolonged downwards on medial artery arises directly from the lateral circumflex femoral artery;
the anterior surface of the muscle; the muscular fibres arise from this the inferior medial (the largest of the three) from the ‘artery of the
aponeurosis. The fibres end in a broad, thick aponeurosis that forms quadriceps’; and the lateral from the first perforating branch given off
over the lower two-thirds of its posterior surface and gradually narrows from the profunda femoris artery.