Bones
1421
48
RETPAHC
attached laterally to the cuboid and blends medially with the tendon to relieve the increased pressure in the compartment surgically results
of tibialis posterior. The middle band is attached laterally to the cuboid in necrosis of the soft tissues within the compartment. The most
and the long plantar ligament, and medially to the medial cuneiform. common cause of compartment syndrome in the foot is trauma, usually
The distal band divides to enclose the tendon of flexor hallucis longus of highenergy (highimpact) type; crush injuries, calcaneal fractures
and is attached to the fascia over flexor hallucis brevis. and disruption of the tarsometatarsal joints are the usual antecedents
associated with compartment syndrome in the foot.
Deep dorsal fascia
The deep fascia on the dorsum of the foot (fascia dorsalis pedis) is a Specialized adipose tissue (heel and
thin layer, continuous above with the inferior extensor retinaculum; it
metatarsal pads)
covers the dorsal extensor tendons and extensor digitorum brevis.
Compartment syndrome in the foot
The heel is subject to repeated high impacts and is anatomically adapted
A compartment syndrome results from an increase in intracompart to withstand these pressures. The adult heel pad has an average thick
mental pressure sufficient to impair venous outflow from that compart ness of 18 mm and a mean epidermal thickness of 0.64 mm (dorsal
ment. As blood enters at arterial pressure, the compartment pressure epidermal thickness averages 0.069 mm). The heel pad contains elastic
increases further until it exceeds arterial pressure, at which point inflow adipose tissue organized as spiral fibrous septa anchored to each other,
of arterial blood ceases, leading to muscle and nerve ischaemia. Failure to the calcaneus and to the skin. The septa are Ushaped, fatfilled
columns designed to resist compressive loads and are reinforced intern
ally with elastic diagonal and transverse fibres, which separate the fat
into compartments.
In the forefoot, the subcutaneous tissue consists of fibrous lamellae
arranged in a complex whorl containing adipose tissue attached via
vertical fibres to the dermis superficially and the plantar aponeurosis


deeply. The fat is particularly thick in the region of the metatarsophalan
geal joints, which cushions the foot during the toeoff phase of gait (see
below). Like the heel pad, the metatarsal fat pad is designed to with
Superficial stand compressive and shearing forces. Atrophy of either may be a cause
transverse of persistent pain in the distal plantar region.
metatarsal
ligament
BONES
Transverse
fascicles
Functionally, the skeleton of the foot may be divided into the tarsus,
metatarsus and phalanges. Anatomically, it may be divided into the
hindfoot (calcaneus and talus), midfoot (navicular, cuboid and cunei
forms), and forefoot (metatarsals, phalanges, and sesamoid bones of
the great toe).
DISTAL TIBIA
The distal end of the tibia has anterior, medial, posterior, lateral and
distal surfaces, and projects inferomedially as the medial malleolus (see
Figs 83.3–83.4). The distal surface, also called the tibial plafond, articu
lates with the talus and is wider anteriorly than posteriorly. It is concave
Medial sagittally and slightly convex transversely, and continues medially into
malleolus Plantar
the malleolar articular surface. The medial malleolus is short and thick,
aponeurosis
Abductor and has a smooth lateral surface with a crescentic or commashaped
hallucis Lateral facet that articulates with the medial surface of the talar body. The
malleolus
distal end of the tibia, including its ossification, is described in detail
on page 1404.
Ligamentous attachments No muscles are attached to the distal
Subcutaneous
calcaneal bursa tibia. The interosseous membrane, the deltoid ligament, and the ante
rior and posterior tibiofibular ligaments are attached to the distal tibia.
Fig. 84.3 The plantar aponeurosis. (With permission from Waschke J, Vascular supply The distal tibia is supplied by an arterial network


Paulsen F (eds), Sobotta Atlas of Human Anatomy, 15th ed, Elsevier, formed by branches of the dorsalis pedis, posterior tibial and fibular
Urban & Fischer. Copyright 2013.) arteries.
Fig. 84.4 A coronal section through the
Tendons of extensor hallucis Tendons of extensor digitorum longus
longus and extensor and extensor digitorum brevis midfoot showing the main fascial
hallucis brevis compartments.
Dorsal fascia
First, second, third and fourth
Adductor hallucis,
dorsal interossei
oblique head
Abductor hallucis Opponens digiti minimi
Tendon of flexor First, second and third
hallucis longus plantar interossei
Abductor digiti minimi
Flexor hallucis brevis
Flexor digiti minimi brevis
Tendons of flexor digitorum
longus and flexor digitorum brevis Plantar aponeurosis


AnklE And fooT
1422
9
noITCES
Innervation The distal tibia is innervated by branches from the deep Vascular supply The distal fibula is supplied by an arterial network
fibular, tibial, saphenous and sural nerves. made up of branches of the dorsalis pedis, posterior tibial and fibular
arteries.
DISTAL FIBULA Innervation The distal fibula is innervated by the deep fibular, tibial,
saphenous and sural nerves.
The distal end of the fibula or lateral malleolus projects distally and
posteriorly relative to the medial malleolus (see Figs 83.3–83.4). Its
lateral aspect is subcutaneous, the posterior surface has a broad groove TARSUS
with a prominent lateral border, and the anterior surface is rough and
somewhat rounded and articulates with the anteroinferior aspect of the The seven tarsal bones occupy the proximal half of the foot (Figs
tibia. The medial surface has a triangular articular facet and is vertically 84.5–84.6). The tarsus and carpus are homologous, but the tarsal ele
convex with its apex directed distally. It articulates with the lateral talar ments are larger, reflecting their role in supporting and distributing
surface. Behind the facet is a rough malleolar fossa for ligamentous body weight. As in the carpus, tarsal bones are arranged in proximal
attachment. The distal end of the fibula, including its ossification, is and distal rows, but medially, there is an additional single intermediate
described in detail on page 1406. tarsal element, the navicular. The proximal row is made up of the talus
and calcaneus; the long axis of the talus is inclined anteromedially and
Ligamentous attachments No muscles are attached to the distal inferiorly, and its distally directed head is medial to the calcaneus and
fibula below the level of the interosseous ligament. The ligamentous at a superior level. The distal row contains, from medial to lateral, the
attachments are those of the lateral ligament complex, i.e. the anterior medial, intermediate and lateral cuneiforms and the cuboid. Collec


talofibular, the calcaneofibular and the posterior talofibular ligaments. tively, these bones display an arched transverse alignment that is dor
The interosseous membrane is attached on its medial aspect. sally convex. Medially, the navicular is interposed between the head of
A B
Extensor digitorum
Flexor hallucis
longus and extensor
digitorum brevis longus Flexor digitorum
longus
Extensor hallucis
longus
Dorsal interossei
Extensor Adductor hallucis
digitorum longus Extensor hallucis and flexor hallucis
brevis brevis
Abductor hallucis
Dorsal Flexor digitorum
Abductor hallucis
interossei brevis
Abductor Plantar interossei Flexor hallucis Abductor digiti
digiti minimi brevis minimi
Plantar interossei
First to
fourth dorsal
First
Second First to interossei
Dorsal
Third interossei third plantar
interossei
Fourth Opponens digiti
Fibularis longus minimi
Medial cuneiform Tibialis anterior A obd ld iqu uc eto hr eh aa dllucis,
Fibularis
Intermediate
tertius
cuneiform Flexor digiti
Lateral cuneiform minimi brevis
Fibularis
brevis Abductor digiti
Tibialis posterior minimi
Navicular
Cuboid Fibularis brevis
Tuberosity of
Flexor hallucis
navicular
brevis
Extensor digitorum Head of talus
Short plantar
brevis Plantar calcaneo-
Neck of talus ligament
navicular ligament
Extensor
Facet for medial digitorum
malleolus brevis
Long plantar
Trochlear surface
Flexor accessorius ligament
Abductor hallucis
Posterior tubercle Abductor digiti
of talus Flexor digitorum minimi
Calcaneus brevis
Calcaneal tendon Plantaris Calcaneal tendon
Attachments from ligamentous and tendinous extensions in the sole of the foot (not direct from bone)
Fig. 84.5 The skeleton of the left foot, with muscle attachments. A, Dorsal aspect. B, Plantar aspect. The attachments of tibialis posterior to the


metatarsals vary; those to the third and fifth metatarsals are sometimes absent.


Bones
1423
48
RETPAHC
1 2 3 4 5 6 7 Appears 9th to 12th week
Appears 6th year
Unites by 18th year
Appears after 15th week
Unites by 18th year
Appears 3rd to 6th year
Appears 11th to 15th week
Unites 18th year
Appears 2nd to 8th year
8 Appears 3rd to 4th year
Unites 17th to 20th year
9
10
Appears 9th week
11
Appears 10th week
A
12 13 14 15 16 17 18 19
Unites 17th to 20th year
Intermediate cuneiform,
9 3rd year Appears 3rd year
10 Lateral cuneiform, Medial cuneiform, 2nd year
1st year
11
12 Cuboid, 9th (fetal) month Navicular, 3rd year
13
1
14
2 15
Talus, 6th (fetal) month
16
17
3
18
Calcaneus, 3rd to 4th (fetal) month
Epiphysis for posterior part
4
of calcaneus appears
6th to 8th year; unites
19 14th to 16th year
5
20 Fig. 84.7 Ossification of the bones of the foot.
6
21
ends of the longitudinal arches. For the purposes of description, each
7
tarsal bone is arbitrarily considered to be cuboidal in form, with six
22
surfaces. The ossification sites and timing of ossification are summa
rized in Figure 84.7.
8
23
Talus
The talus is an intercalated bone with no tendinous attachments. It is
the osseous link between the foot and leg through the ankle joint (see
Figs 84.16 and 84.18).
B
Head Directed distally and somewhat inferomedially, the head has a
distal surface, which is ovoid and convex; its long axis is also inclined


Fig. 84.6 A, A lateral radiograph of the adult ankle and foot in full
inferomedially to articulate with the proximal navicular surface (see Fig.
plantigrade contact with the ground, during symmetrical standing, in a
man aged 24 years. Key: 1, fibula; 2, tibia; 3, talar neck; 4, talar head; 5, 84.5A). The plantar surface of the head has three articular areas, sepa
talonavicular joint; 6, navicular; 7, medial cuneiform; 8, talocrural joint; 9, rated by smooth ridges (Fig. 84.8C). The most posterior and largest is
talar body; 10, posterior process of talus; 11, subtalar joint; 12, calcaneus oval and slightly convex, and rests on a shelflike medial calcaneal
(note the trabecular pattern); 13, tarsal sinus; 14, calcaneocuboid joint; projection, the sustentaculum tali. Anterolateral to this and usually
15, cuboid; 16, styloid process of the fifth metatarsal; 17, base of the first continuous with it, a flat articular facet rests on the anteromedial part
metatarsal; 18, shaft of the first metatarsal; 19, head of the first of the dorsal (proximal) calcaneal surface; distally, it continues into the
metatarsal. B, A dorsoplantar radiograph of adult foot in full plantigrade navicular surface. Between the two calcaneal facets, a part of the talar
contact with the ground, during symmetrical standing, in a man aged 24 head, covered with articular cartilage, is in contact with the plantar
years. Key: 1, interphalangeal joint; 2, middle phalanx; 3, head of fifth calcaneonavicular (spring) ligament, which is covered here, superiorly,
metatarsal; 4, shaft of fifth metatarsal; 5, base of fifth metatarsal; 6, lateral by fibrocartilage (see Fig. 84.13B). When the foot is inverted passively,


cuneiform; 7, cuboid; 8, calcaneus; 9, head of distal phalanx; 10, shaft of the dorsolateral aspect of the head is visible and palpable approxi
distal phalanx; 11, base of distal phalanx; 12, head of proximal phalanx; mately 3 cm distal to the tibia; it is hidden by extensor tendons when
13, shaft of proximal phalanx; 14, base of proximal phalanx; 15, first
the toes are dorsiflexed.
metatarsophalangeal joint; 16, lateral (fibular) sesamoid; 17, medial (tibial)
sesamoid; 18, shaft of first metatarsal; 19, first metatarsocuneiform joint; Neck The neck is the narrow, medially inclined region between the
20, medial cuneiform; 21, intermediate cuneiform; 22, tuberosity of
head and body. Its rough surfaces are for ligaments. The medial plantar
navicular; 23, talar head. (Courtesy of New York College of Podiatric
surface has a deep sulcus tali that, when the talus and calcaneus are
Medicine, New York, NY.)
articulated, forms a roof to the tarsal sinus, which is occupied by inter
osseous talocalcaneal and cervical ligaments.
the talus and the cuneiforms. Laterally, the calcaneus articulates with The long axis of the neck, inclined downwards, distally and medially,
the cuboid. makes an angle of approximately 150° with that of the body; it is
The tarsus and metatarsus are arranged to form intersecting longitu smaller (130–140°) at birth, accounting in part for the inverted foot in
dinal and transverse arches. Hence, thrust and weight are not transmit young children. The dorsal talonavicular ligament and ankle articular
ted from the tibia to the ground (or vice versa) directly through the capsule are attached distally to the dorsal surface of the talus. Thus, the
tarsus, but are distributed through the tarsals and metatarsals to the proximal part of this surface lies within the capsule of the ankle joint.


48
RETPAHC
Ankle and foot
In a hypermobile flat foot undergoing pronation, the talar head is
unsupported medially by the sustentaculum tali. The resulting lack of
support results in a visible medial protrusion of the talar head as the
foot adducts and plantar flexes towards the ground (Michaud 2011).
1423.e1


AnklE And fooT
1424
9
noITCES
The medial articular facet of the talar body and part of the trochlear The middle third of the talar body, other than its most superior aspect,
surface may extend on to the neck. The anterior talofibular ligament is and the lateral third, other than its posterior aspect, are supplied mainly
attached on the lateral aspect of the neck, spreading along the adjacent by the anastomotic arcade in the tarsal canal. The medial third of the
anterior border of the lateral surface. The interosseous talocalcaneal and body of the talus is supplied by the branch of the artery of the tarsal
cervical ligaments are attached to the inferior surface of the neck. A canal to the deltoid ligament.
dorsolateral, socalled ‘squatting facet’ is commonly present on the talar
neck in those individuals who habitually adopt the squatting position; Innervation The talus is innervated by branches from the deep fibular,
it articulates with the anterior tibial margin in extreme dorsiflexion and tibial, saphenous and sural nerves.
may be doubled.
Ossification A single ossification centre appears prenatally at 6
Body The body is cuboidal, covered dorsally by a trochlear surface months (see Fig. 84.7). The posterolateral process sometimes fuses with
articulating with the distal end of the tibia. It is anteroposteriorly an accessory bone called the os trigonum.
convex, gently concave transversely, widest anteriorly and, therefore,
sellar in shape. The triangular lateral surface is smooth and vertically Talar fractures Since 70% of the surface of the talus is covered by
concave for articulation with the lateral malleolus. Superiorly, it is articular cartilage, displaced talar neck fractures, where the blood supply
continuous with the trochlear surface; inferiorly, its apex is a lateral to the talar body is interrupted, may result in avascular necrosis and
process. Proximally, the medial surface is (posterosuperiorly) covered nonunion. Transchondral fractures of the superior aspect of the talus


by a commashaped facet, which is deeper in front and articulates with are frequently overlooked on initial radiographs of patients with ankle
the medial malleolus. Distally, this surface is rough and contains complaints (Trepal et al 1986). A systematic review by Halvorson et al
numerous vascular foramina. The small posterior surface features a (2012) reported that approximately 33% of talar neck fractures progress
rough projection termed the posterior process. The process is marked to avascular necrosis, 20% progress to malunions and 5% progress to
by an oblique groove between two tubercles. The lateral tubercle is nonunions. In general, these complications do not occur in non
usually larger; the medial is less prominent and lies immediately behind displaced fractures. If a subchondral lucency is seen in the talus on
the sustentaculum tali. The plantar surface articulates with the middle radiographs at 8 weeks after fracture of the talar neck (Hawkins sign),
third of the dorsal calcaneal surface by an oval concave facet, its long it may be assumed that vascularity to the talar body is intact and that
axis directed distolaterally at an angle of approximately 45° with the the fracture is likely to heal satisfactorily.
median plane. The medial edge of the trochlear surface is straight, but
Calcaneus
its lateral edge inclines medially in its posterior part and is often broad
ened into a small, elongated triangular area, which is in contact with The calcaneus is the largest of the tarsal bones and projects posterior
the posterior tibiofibular ligament in dorsiflexion. to the tibia and fibula as a short lever for muscles of the calf attached
The posterior talofibular ligament is attached to the lateral tubercle to its posterior surface. It is irregularly cuboidal, its long axis being
of the posterior process (posterolateral tubercle). Its attachment extends inclined distally upwards and laterally (see Fig. 84.8A,B). It has a rela
up to the groove, or depression, between the process and posterior tively thin cortex (Daftary et al 2005). The superior or proximal surface


trochlear border. The posterior talocalcaneal ligament is attached to the is divisible into three areas. The posterior third is rough and concavo
plantar border of the posterior process. The groove between the tuber convex; the convexity is transverse and supports fibroadipose tissue
cles of the process contains the tendon of flexor hallucis longus and (Kager’s fat pad) between the calcaneal tendon and ankle joint. The
continues distally into the groove on the plantar aspect of the susten middle third carries the posterior talar facet, which is oval and convex
taculum tali. The medial talocalcaneal ligament is attached below to anteroposteriorly. The anterior third is partly articular; distal (anterior)
the medial tubercle, whereas the most posterior superficial fibres of to the posterior articular facet, a rough depression, the calcaneal sulcus,
the deltoid ligament are attached above the tubercle. The deep fibres narrows into a groove on the medial side and completes the tarsal sinus
of the deltoid ligament are attached more superiorly to the rough area with the talus (see Fig. 84.8B). (The tarsal sinus is a conical hollow
immediately below the commashaped articular facet on the medial bounded by the talus medially, superiorly and laterally, with the supe
surface. rior surface of the calcaneus below. Its medial end is narrow and tunnel
shaped, and is often referred to as the tarsal canal.) Distal and medial
Ligamentous attachments No muscles are attached to the talus. to this groove, an elongated articular area covers the sustentaculum tali
However, many ligaments are attached to the bone, and these confer (talar shelf) and extends distolaterally on the body of the bone. This
stability to the talocrural, subtalar and talocalcaneonavicular joints. facet is often divided into middle and anterior talar facets by a non
articular interval at the anterior limit of the sustentaculum tali (the
Vascular supply The talar blood supply is rather tenuous because incidence of this subdivision varies with sex, race and occupation).
of the lack of muscle attachments. The first comprehensive account of Rarely, all three facets on the upper surface of the calcaneus are fused


talar blood supply was provided by Wildenauer in 1950. The extraos into one irregular area.
seous blood supply is via the posterior tibial, dorsalis pedis and fibular The anterior surface is the smallest, and is an obliquely set concavo
arteries (Fig. 84.9). The ‘artery of the tarsal canal’ arises from the pos convex articular facet for the cuboid. The posterior surface is divided
terior tibial artery approximately 1 cm proximal to the origin of the into three regions: a smooth proximal (superior) area separated from
medial and lateral plantar arteries (Fig. 84.10) and passes anteriorly the calcaneal tendon by a bursa and adipose tissue; a middle area,
between the sheaths of flexor digitorum longus and flexor hallucis which is the largest, limited above by a groove and below by a rough
longus to enter the tarsal canal, in which it lies anteriorly, close to the ridge for the calcaneal tendon; and a distal (inferior) area, vertically
talus. (The ‘tarsal canal’ is the term that is commonly used to describe striated and inclined downwards and forwards, which is the subcutan
the tunnelshaped medial end of the tarsal sinus.) Branches from the eous weightbearing surface.
arterial network in the tarsal canal enter the talus. The artery continues The plantar surface is rough, especially proximally as the calcaneal
through the tarsal canal into the lateral part of the tarsal sinus, where tuberosity, the lateral and medial processes of which extend distally,
it anastomoses with the artery of the tarsal sinus, forming a vascular separated by a notch. The medial process is longer and broader (see Fig.
sling under the talar neck. A branch of the artery of the tarsal canal 84.8B). Further distally, an anterior tubercle marks the distal limit of
known as the deltoid branch passes deep to the deltoid ligament and the attachment of the long plantar ligament.
supplies part of the medial aspect of the talar body. Sometimes, it arises The lateral surface is almost flat. It is proximally deeper and palpable


from the posterior tibial artery; rarely, it arises from the medial plantar on the lateral aspect of the heel distal to the lateral malleolus. Distally,
artery; it may be the only remaining arterial supply to the talus when it presents the fibular trochlea (see Fig. 84.8A,B), which is exceedingly
this bone is fractured. The dorsalis pedis artery supplies branches to the variable in size and palpable 2 cm distal to the lateral malleolus when
superior aspect of the talar neck and also gives off the artery of the tarsal well developed. It bears an oblique groove for the tendon of fibularis
sinus. This large vessel is always present and anastomoses with the longus and a shallower proximal groove for the tendon of fibularis
artery of the tarsal canal. The artery of the tarsal sinus receives a contri brevis. About 1 cm or more behind and above the fibular trochlea, a
bution from the anterior perforating branch of the fibular artery and second elevation may exist for attachment of the calcaneofibular part
supplies direct branches to the talus. The fibular artery provides small of the lateral ligament.
branches, which form a plexus of vessels posteriorly with branches of The medial surface is vertically concave, and its concavity is accentu
the posterior tibial artery; however, the contribution that the fibular ated by the sustentaculum tali, which projects medially from the distal
artery makes to the talar blood supply is thought to be insignificant. part of its upper border (see Fig. 84.8B). Superiorly, the process bears
The intraosseous blood supply of the talar head arises medially from the middle talar facets and inferiorly a groove, which is continuous with
branches of the dorsalis pedis and laterally via vessels that arise from that on the talar posterior surface for the tendon of flexor hallucis
the anastomosis between the arteries of the tarsal canal and tarsal sinus. longus (see Fig. 84.8A,B). The medial aspect of the sustentaculum tali


48
RETPAHC
Ankle and foot
This accessory bone is occasionally found and arises from a separate
ossification centre that appears between 8 and 11 years of age. When
the os trigonum fuses to the posterolateral process of the talus it is
called the trigonal process (Stieda’s process). Another accessory bone
(although rare) of the foot is the os supratalare, which lies on the dorsal
aspect of the talus; it rarely measures more than 4 mm in length.
A detailed analysis of patterns of anterior talar articular facets in a
series of 401 Indian calcanei revealed four types. Type I (67%) showed
one continuous facet on the sustentaculum extending to the disto
medial calcaneal corner; type II (26%) presented two facets, one sus
tentacular and one distal calcaneal; type III (5%) possessed only a single
sustentacular facet; and type IV (2%) showed confluent anterior and
posterior facets (Gupta et al 1977).
1424.e1


Bones
1425
48
RETPAHC
A Foot bones Talus
Medial aspect Navicular
Intermediate cuneiform
Medial cuneiform
Calcaneus
Metatarsals
Proximal
phalanges
Middle
phalanges
Groove for tendon of Distal
flexor hallucis longus phalanges
Talus
Lateral aspect Navicular
Intermediate cuneiform
Lateral cuneiform
Calcaneus
Metatarsals
Phalanges
Fibular trochlea
Cuboid
B Calcaneus For cuboid
Anterior articular
surface for talus
Anterior tubercle
Middle articular
Sustentaculum tali
surface for talus
Groove for tendon Fibular trochlea
of flexor hallucis Calcaneal sulcus
longus
Posterior articular
surface for talus
Medial process
Lateral process
Calcaneal tuberosity
Inferior aspect Superior aspect
Sustentaculum tali Calcaneal sulcus
Posterior articular
surface for talus Middle articular Posterior articular
surface for talus surface for talus
Anterior articular
For calcaneofibular
surface for talus
ligament
Posterior surface
Fibular trochlea
Lateral process of
Anterior tubercle calcaneal tuberosity
Medial aspect Lateral aspect
For navicular
C Talus For anterior
calcaneal surface
For calcaneonavicular
ligament For medial malleolus
For lateral malleolus
For distal end
Sulcus tali of tibia
Posterior
calcaneal surface
Inferior aspect Superior aspect
For distal end of tibia
Neck
For lateral malleolus
For medial malleolus
Head
For navicular Posterior calcaneal
surface
Medial aspect Lateral aspect
Fig. 84.8 The skeleton of the foot. A, Foot bones. B, Calcaneus. C, Talus. (With permission from Drake RL, Vogl AW, Mitchell A, et al (eds), Gray’s Atlas
of Anatomy, Elsevier, Churchill Livingstone. Copyright 2008.)


AnklE And fooT
1426
9
noITCES
to the tubercle and the area distal to it. The lateral tendinous head of
Fibular artery Posterior tibial
artery flexor accessorius is attached distal to the lateral process near the lateral
Anterior tibial artery margin of the long plantar ligament. Plantaris is attached to the poste
Perforating branch
rior surface near the medial side of the calcaneal tendon. The anterior
Anterior medial malleolar artery of fibular artery part of the lateral surface is crossed by the fibular tendons but is largely
subcutaneous. The calcaneofibular ligament is attached 1–2 cm proxi
Anterior lateral malleolar artery Communicating
mal to the fibular trochlea, usually to a low, rounded elevation.
branch
Lateral tarsal artery The dorsal surface of the sustentaculum tali is part of the talocalca
Dorsalis pedis artery neonavicular joint; its plantar surface is grooved by the tendon of flexor
Posterior medial hallucis longus, and margins of the groove give attachment to the deep
malleolar branch
of posterior tibial part of the flexor retinaculum. The plantar calcaneonavicular ligament
artery is attached distally to the medial margin of the sustentaculum, which
is narrow, rough and convex. A slip from the tendon of tibialis posterior,
Medial plantar
artery and superficial fibres of the deltoid ligament and medial talocalcaneal
ligaments are attached proximally. Distal to the attachment of the
Lateral plantar deltoid ligament, the tendon of flexor digitorum longus is related to
artery the margin of the sustentaculum tali and may groove it. The large
medial head of flexor accessorius is attached distal to the groove for
flexor hallucis longus.
Vascular supply The calcaneus receives its arterial supply from the
medial and lateral calcaneal arteries (arising from the posterior tibial
and fibular arteries, respectively), fibular artery, posterior calcaneal
Arcuate artery anastomosis (formed from the posterior tibial and fibular arteries),
medial and lateral plantar arteries, artery of the tarsal sinus and tarsal
Calcaneal branches of canal, branches of the lateral tarsal artery and perforating fibular


fibular artery arteries.
Calcaneal branches of posterior
tibial and lateral plantar arteries
Innervation The calcaneus is innervated by branches of the tibial,
Fig. 84.9 The arterial anastomoses of the ankle, tarsus and metatarsus. sural and deep fibular nerves.
Ossification The calcaneus is the only tarsal bone that always has
two ossification centres (see Fig. 84.7). In addition to the main ossifica
tion centre, there is a scalelike posterior apophysis that covers most of
the posterior, and part of the plantar, surfaces. The main centre appears
prenatally in the third month, whereas the posterior apophysis appears
in the sixth year in females and the eighth year in males, fusing in the
Calcaneal tendon fourteenth and sixteenth years, respectively.
Tendon of tibialis posterior
An os calcaneus secundarius, an accessory bone rather than a sec
ondary ossification centre, occasionally occurs. When present, it is
located on the socalled anterior process of the calcaneus, from which
Posterior tibial artery Tendon of flexor digitorum longus
the bifurcate ligament arises, in an interval between the anteromedial
aspect of the calcaneus, the proximal ends of the cuboid and navicular,
Artery of the tarsal canal and the head of the talus. Other rare accessory bones of the calcaneus
Tendon of flexor include the calcaneus accessorius in the region of the fibular trochlea;
hallucis longus the os sustentaculi on the posterior aspect of the sustentaculum tali; the
os subcalcis on the plantar aspect of the calcaneus slightly posterior to
the origin of the plantar aponeurosis; and the os aponeurosis plantaris,
which lies within the plantar aponeurosis in close proximity to the
Calcaneal
branches medial process of the calcaneal tuberosity.
Navicular
The navicular articulates with the talar head proximally and with the
cuneiform bones distally (see Fig. 84.8A; Fig. 84.11). In convex pes
planovalgus (vertical talus), the navicular is subluxed dorsally and


Fig. 84.10 Branches of the posterior tibial artery, posteromedial view of
the ankle. articulates instead with the talar neck. The downward displacement of
the talar head creates a characteristic convex ‘rockerbottom foot’. The
distal surface of the navicular is transversely convex and divided into
three facets (the medial being the largest) for articulation with the
can be felt immediately distal to the tip of the medial malleolus; occa cuneiforms. The proximal surface is oval and concave, and articulates
sionally, it is also grooved by the tendon of flexor digitorum longus. with the talar head. The dorsal surface is rough and convex. The medial
surface is also rough and projects proximally as a prominent tuberosity,
Muscle and ligamentous attachments The interosseous talo palpable approximately 2.5 cm distal and plantar to the medial malleo
calcaneal and cervical ligaments and the medial root of the inferior lus. The plantar surface, rough and concave, is separated from the
extensor retinaculum are attached in the calcaneal sulcus. The non tuberosity medially by a groove for the tendon of tibialis posterior. The
articular area distal to the posterior talar facet is the site of attachment lateral surface is rough and irregular, and often bears a facet for articula
of extensor digitorum brevis (in part), the principal band of the inferior tion with the cuboid.
extensor retinaculum and the stem of the bifurcate ligament. The facet for articulation with the medial cuneiform is roughly tri
Abductor hallucis and the superficial part of the flexor retinaculum angular, its rounded apex is medial and its ‘base’, facing laterally, is
and, distally, the plantar aponeurosis and flexor digitorum brevis are often markedly curved; the articular facets for the intermediate and
all attached to the medial process (medial condyle) of the calcaneal lateral cuneiforms are also triangular, with plantarfacing apices. The
tuberosity at its prominent medial margin. The medial process of the facet for the lateral cuneiform may appear as a wide crescent or a semi


calcaneal tuberosity is the primary weightbearing portion of the cal circle rather than a triangle. Dorsal talonavicular, cuneonavicular and
caneus. Clinically, pain over the medial tuberosity is often associated cubonavicular ligaments are attached to the dorsal navicular surface.
with plantar fasciitis (Yi et al 2011). Abductor digiti minimi is attached
to the lateral process, extending medially to the medial process. The Muscle and ligamentous attachments The navicular tuberosity
long plantar ligament is attached to the rough region between the pro is the main attachment of tibialis posterior, and a groove lateral to it
cesses proximally, and extends to the anterior tubercle distally. The transmits part of the tendon distally to the cuneiforms and middle three
plantar calcaneocuboid ligament (short plantar ligament) is attached metatarsal bases. The plantar calcaneonavicular ligament is attached to


48
RETPAHC
Ankle and foot
Calcaneal apophysitis (Sever’s disease) is a selflimiting inflamma
tory condition seen in some child athletes, boys more commonly than
girls. It is not a true apophysitis and the use of imaging for its initial
diagnosis is a subject of controversy (Kose 2010, Rachel et al 2011).
Calcaneal apophysitis is often treated with stretching, therapeutic heel
lifts, icing and nonsteroidal antiinflammatory drugs (Micheli and
Ireland 1987).
1426.e1


Bones
1427
48
RETPAHC
Second metatarsal Fig. 84.11 The skeleton
Third metatarsal of the tarsals and
metatarsals, dorsal
aspect. (With permission
from Waschke J, Paulsen
Fourth metatarsal F (eds), Sobotta Atlas of
Human Anatomy, 15th ed,
Elsevier, Urban & Fischer.
First metatarsal
Copyright 2013.)
I
II
III
Head
IV
Tuberosity of first metatarsal
V
Fifth metatarsal Shaft Medial cuneiform
Intermediate cuneiform
Base
Tuberosity Lateral cuneiform
Groove for tendon
of fibularis longus Navicular
Tuberosity
Cuboid Tuberosity
metatarsal part
Calcaneal articular facet
a slight projection lateral to the groove and adjacent to the proximal Cuboid
surface. The calcaneonavicular part of the bifurcate ligament is attached
The cuboid, the most lateral bone in the distal tarsal row, lies between
to the rough part of the lateral surface (see Fig. 84.5B).
the calcaneus proximally and the fourth and fifth metatarsals distally
(see Figs 84.8A, 84.11). Its dorsolateral surface is rough for the attach
Vascular supply The dorsal aspect of the navicular is supplied either
ment of ligaments. The plantar surface is crossed distally by an
from a branch of, or directly from, the dorsalis pedis artery. The medial
oblique groove for the tendon of fibularis longus and bounded proxi
plantar artery supplies its plantar aspect, and the tuberosity is supplied
mally by a ridge that ends laterally in the tuberosity of the cuboid,
by an anastomosis between the dorsalis pedis and medial plantar
the lateral aspect of which is faceted for a sesamoid bone or cartilage
arteries.
that is frequently found in the tendon of fibularis longus. Proximal to
its ridge, the rough plantar surface extends proximally and medially
Innervation The navicular is innervated by the deep fibular and
because of the obliquity of the calcaneocuboid joint, making its
medial plantar nerves.


medial border much longer than the lateral. The lateral surface is
rough; the groove for fibularis longus extends from a deep notch on
Ossification The navicular ossification centre appears during the
its plantar edge. The medial surface, which is much more extensive
third year (see Fig. 84.7). It is sometimes affected by avascular necrosis
and partly nonarticular, bears an oval facet for articulation with the
between the ages of 4 and 7 years (Köhler’s disease). An accessory
lateral cuneiform, and proximal to this another facet (sometimes
navicular bone, which is considered an anatomical variant, occasionally
absent) for articulation with the navicular; the two form a continuous
occurs. It arises from a separate ossification centre in the region of the
surface separated by a smooth vertical ridge. The distal surface is
posteromedial aspect of the navicular tuberosity. There are three distinct
divided vertically into a medial quadrilateral articular area for the
types of accessory navicular. Type I is probably a sesamoid bone within
base of the fourth metatarsal and a lateral triangular area, its apex
the plantar aspect of the tendon of tibialis posterior at the level of the
lateral, for the base of the fifth metatarsal. The proximal surface, trian
inferior calcaneonavicular ligament. In type II, the accessory bone is
gular and concavoconvex, articulates with the distal calcaneal surface;
separated from the body of the navicular by a synchondrosis. These
its medial plantar angle projects proximally and inferiorly to the
types are sometimes known as os tibiale externum or naviculare
distal end of the calcaneus.
secundarium. Type III is commonly called the cornuate navicular or
gorilloid navicular (Barnes 2003), where the accessory bone is united
Muscle and ligamentous attachments The dorsal calcaneo
to the navicular by a bony ridge, and may represent the possible end
cuboid, cubonavicular, cuneocuboid and cubometatarsal ligaments are
stage of type II. An accessory navicular may be the source of pain in
attached to the dorsal surface. Deep fibres of the long plantar ligament


athletes. Type II is the most commonly symptomatic variant; it has been
are attached to the proximal edge of the plantar ridge. Slips from the
suggested that the pull of the tendon of tibialis posterior, the degree of
tendons of tibialis posterior and flexor hallucis brevis are attached to
foot pronation, and the location of the accessory bone in relation to
the projecting proximomedial part of the plantar surface. Interosseous,
the undersurface of the navicular may produce tension, shear and/or
cuneocuboid and cubonavicular ligaments are attached to the rough
compression forces on the synchondrosis. An accessory navicular is one
part of the medial cuboidal surface. Proximally, the medial calcane
aetiology of posterior tibial tendon dysfunction (PTTD). The altered
ocuboid ligament, which is the lateral limb of the bifurcate ligament,
mechanics cause abnormal stresses, leading to tendon degeneration,
is also attached to this surface. The placement and trapezoidal shape of
decreased strength and possible tendon rupture.
the cuboid give it the ability to act as the ‘keystone’ of the lateral lon Rarely, the navicular is bipartite and it arises from two distinct
gitudinal arch of the foot. During locomotion, the tension of the cal
centres of ossification. This can lead to premature degeneration within
caneocuboid joint helps ‘lock’ the midtarsal joint and acts as a major
the talocalcaneonavicular joint (Müller–Weiss disease). Occasionally, a
stabilizer of the foot.
small bone is found within the talocalcaneonavicular joint on its dorsal
aspect. Referred to as an os talonaviculare dorsale, it represents either a
separate accessory bone or a fractured osteophyte of the proximal dorsal Vascular supply The cuboid is supplied by deep branches of the
aspect of the navicular. A bipartite navicular is sometimes found with medial and lateral plantar arteries and by branches from the dorsal
cuneonavicular coalitions. arterial network.


AnklE And fooT
1428
9
noITCES
Innervation The cuboid is innervated by branches from the lateral Muscle attachments Part of the tendon of tibialis posterior is
plantar, sural and deep fibular nerves. attached to the intermediate cuneiform.
Ossification The cuboid frequently begins to ossify before birth, the Vascular supply The intermediate cuneiform is supplied via its
primary ossification centre appearing just before birth (see Fig. 84.7). dorsal, medial and lateral surfaces, mainly from the dorsal arterial
An os cuboides secundarium is a rare accessory bone situated on the network.
plantar aspect of the cuboid and is sometimes involved in the infre
quently reported cubonavicular coalitions. Innervation The intermediate cuneiform is innervated by the deep
fibular and medial plantar nerves.
Cuneiforms
Ossification The ossification centre appears during the third year of
The wedgelike cuneiform bones articulate with the navicular proxi life (see Fig. 84.7). The os cuneo2 metatarsaleII dorsale, a rare acces
mally and with the bases of the first to third metatarsals distally; the sory bone, lies on the dorsal aspect of the joint between the intermedi
medial cuneiform is the largest, the intermediate the smallest. The ate cuneiform and the second metatarsal. It is wedgeshaped with its
dorsal surfaces of the intermediate and lateral cuneiforms form the base base orientated dorsally.
of the wedge. The wedge is reversed in the medial cuneiform, which is
Lateral cuneiform
a prime factor in shaping the transverse arch. The proximal surfaces of
all three form a concavity for the distal surface of the navicular. The The lateral cuneiform lies between the intermediate cuneiform and
medial and lateral cuneiforms project distally beyond the intermediate cuboid, and also articulates with the navicular and, distally, with the
cuneiform and so form a recess (mortise) for the second metatarsal third metatarsal base (see Figs 84.5A, 84.11). Like the intermediate
base. cuneiform, its dorsal surface, which is rough and almost rectangular, is


the base of a wedge. The plantar surface is narrow and receives a slip
Medial cuneiform from tibialis posterior and sometimes part of flexor hallucis brevis. The
The medial cuneiform (see Figs 84.5, 84.8A, 84.11) articulates with the distal surface is a triangular articular facet for the third metatarsal base.
navicular and base of the first metatarsal. It has a rough, narrow dorsal The proximal surface is rough on its plantar aspect, but its dorsal two
surface. The distal surface is a kidneyshaped facet for the first metatarsal thirds articulate with the navicular by a triangular facet. The medial
base, its ‘hilum’ being lateral. The proximal surface bears a piriform surface is partly nonarticular and has a vertical segment, indented by
facet for the navicular, which is concave vertically and dorsally nar the intermediate cuneiform, on its proximal margin; on its distal
rowed. The medial surface, rough and subcutaneous, is vertically convex; margin, a narrower strip (often two small facets) articulates with the
its distal plantar angle carries a large impression, which receives the lateral side of the second metatarsal base. The lateral surface, also partly
principal attachment of the tendon of tibialis anterior (see Fig. 84.5B). nonarticular, bears a triangular or oval proximal facet for the cuboid;
The lateral surface is partly nonarticular; there is a smooth rightangled a semilunar facet on its dorsal and distal margin articulates with the
strip along its proximal and dorsal margins for the intermediate cunei dorsal part of the medial side of the fourth metatarsal base. Non
form. Its distal dorsal area is separated by a vertical ridge from a small, articular areas of the medial and lateral surfaces receive intercuneiform
almost square, facet for articulation with the dorsal part of the medial and cuneocuboid ligaments, respectively, which are important in the
surface of the second metatarsal base. Plantar to this, the medial cunei maintenance of the transverse arch of the foot.
form is attached to the medial side of the second metatarsal base by a
strong ligament (Lisfranc’s ligament). Proximally, an intercuneiform Muscle attachments The plantar surface of the lateral cuneiform


interosseous ligament connects this surface to the intermediate cunei receives a slip from the tendon of tibialis posterior and, occasionally,
form. The distal and plantar areas of the surface are roughened by part of flexor hallucis brevis.
attachment of part of the tendon of fibularis longus.
Vascular supply The lateral cuneiform is supplied via its dor
Muscle attachments The plantar surface receives a slip from the sal, medial and lateral surfaces, mainly from the dorsal arterial
tendon of tibialis posterior, in addition to part of the insertion of the network.
tendon of fibularis longus. The medial surface receives the attachment
of most of the tendon of tibialis anterior. Innervation The lateral cuneiform is innervated by branches of the
deep fibular and lateral plantar nerves.
Vascular supply The medial cuneiform is supplied via its dorsal,
medial and lateral surfaces, mainly from the dorsal arterial network. Ossification The lateral cuneiform ossifies during the first year of life
(see Fig. 84.7).
Innervation The medial cuneiform is supplied by the deep fibular and
Tarsal coalition
medial plantar nerves.
Tarsal coalition is a hereditary condition in which there is a fibrous,
Ossification The medial cuneiform may have two separate ossific cartilaginous or osseous union of two or more tarsal bones. The
ation centres, which appear during the second year of life (see Fig. aetiology of tarsal coalition is unclear; suggestions include genetic pre
84.7). Very rarely, the medial cuneiform is bipartite and there is a hori disposition, failure of segmentation of primitive mesenchyme, trauma,
zontal cleavage plane between the two parts. arthritic changes, and/or osteochondroses of the tarsal bones (e.g.
The os cuneo1 metatarsaleI plantare is a rare accessory bone that Köhler’s disease) (Gregersen 1977, Zaw and Calder 2010, Lemley et al
occurs on the plantar aspect of the foot at the base of the first metatarsal 2006, Harris 1965, Varner and Michelson 2000).
and articulates with the plantar base of the first metatarsal and the
medial cuneiform.
METATARSUS
Intermediate cuneiform


The intermediate (middle) cuneiform articulates proximally with the The five metatarsals lie in the distal half of the foot and connect the
navicular and distally with the second metatarsal base (see Figs 84.5A, tarsus with the phalanges. Like the metacarpals, they are miniature long
84.11). It has a narrow plantar surface that receives a slip from the bones and have a shaft, proximal base and distal head. Except for the
tendon of tibialis posterior. The distal and proximal surfaces are both first and fifth, the shafts are long and slender, longitudinally convex
triangular articular facets. The medial surface is partly articular; it articu dorsally, and concave on their plantar aspects. Prismatic in section, they
lates via a smooth, angled region that is occasionally double with the taper distally. Their bases articulate with the distal tarsal row and with
medial cuneiform along its proximal and dorsal margins. The lateral adjacent metatarsal bases. The line of each tarsometatarsal joint, except
surface is also partly articular; along its proximal margin a vertical the first, inclines proximally and laterally with the metatarsal bases
segment, usually indented, abuts the lateral cuneiform. Strong interos being oblique relative to their shafts. The heads articulate with the
seous ligaments connect the nonarticular parts of both surfaces to the proximal phalanges, each by a convex surface that passes farther on to
adjacent cuneiforms. An intricate arrangement of dorsal and plantar its plantar aspect, where it ends on the summits of two eminences. The
ligaments spans the tarsometatarsal joint, connecting the most distal sides of the heads are flat, with a depression surmounted by a dorsal
row of tarsals to their respective metatarsals. However, the plantar liga tubercle for a collateral ligament of the metatarsophalangeal joint.
ment between the intermediate cuneiform and the base of the second On occasion, an os intermetatarseum is encountered between the
metatarsal is uniquely absent (Castro et al 2010, Chaney 2010, de Palma medial cuneiform and the bases of the first and second metatarsals and


et al 1997, Blouet et al 1983). represents a rare accessory bone in this region.


48
RETPAHC
Ankle and foot
Harris and Beath (1948) were the first to recognize an association
between tarsal coalitions and ‘peroneal (fibular) spastic flat foot’. The
two most common examples are talocalcaneal and calcaneonavicular
coalitions, which usually present with symptoms early in the second
decade of life. They are often, but not invariably, associated with flat
feet (pes planus). A talonavicular coalition is rare (Brennan et al 2012),
but when present, it is often associated with a ‘ballandsocket’ ankle
joint. Surgical resection of tarsal coalitions may eradicate associated
pain but seldom improves the range of movement.
1428.e1


Bones
1429
48
RETPAHC
Individual metatarsals metatarsal head starts between the third and fourth years; fusion occurs
between the seventeenth and twentieth years.
First metatarsal Third metatarsal
The first metatarsal (see Figs 84.5, 84.11) is the shortest and thickest, The third metatarsal (see Figs 84.5, 84.11) has a flat triangular base,
and has a strong shaft, of marked prismatic form. The base sometimes articulating proximally with the lateral cuneiform, medially with the
has a lateral facet or illdefined smooth area as a result of contact with second metatarsal, via dorsal and plantar facets, and laterally, via a
the second metatarsal. Its large proximal surface, usually indented on single facet, with the dorsal angle of the fourth metatarsal. The medial
the medial and lateral margins, articulates with the medial cuneiform. plantar facet is frequently absent. The third tarsometatarsal joint is
Its circumference is grooved for tarsometatarsal ligaments and, medi relatively immobile and predisposes the third metatarsal to stress
ally, part of the tendon of tibialis anterior is attached; its plantar angle fracture.
has a rough, oval, lateral prominence for the tendon of fibularis longus.
The medial head of the first dorsal interosseous is attached to the flat Muscle attachments The lateral heads of the second dorsal interos
lateral surface of the shaft. The large head has a plantar elevation, the seous and first plantar interosseous are attached to the medial surface
crista, which separates two grooved facets (of which the medial is of the shaft. The medial head of the third dorsal interosseous is attached
larger), on which sesamoid bones glide. The most common joint to its lateral surface.
deformity related to the first metatarsal is hallux valgus.
Vascular supply The blood supply of the third metatarsal is the same
Muscle attachments The first metatarsal receives attachments from as that of the second metatarsal, described above.
the tendon of tibialis anterior medially, and the tendon of fibularis


longus on its plantar aspect. It gives origin to the medial head of the Innervation The third metatarsal is innervated by the deep fibular and
first dorsal interosseus on the proximal aspect of the lateral surface. lateral plantar nerves.
Vascular supply The first metatarsal is supplied by the first dorsal Ossification There are two centres of ossification, one in the shaft
and first plantar metatarsal arteries and a superficial branch of the and one distally in the metatarsal head (see Fig. 84.7). Ossification of
medial plantar artery, which together form a periosteal arterial network. the shaft starts during the ninth prenatal week and ossification of the
A nutrient artery enters the lateral surface of the middiaphysis. The metatarsal head starts between the third and fourth years; fusion occurs
head receives a medial, lateral and plantar supply from these arteries. between the seventeenth and twentieth years.
Fourth metatarsal
Innervation The first metatarsal is innervated by the deep fibular and
The fourth metatarsal is smaller than the third (see Figs 84.5, 84.11).
medial plantar nerves.
Its base has, proximally, an oblique quadrilateral facet for articulation
Ossification The first metatarsal has two centres of ossification, one with the cuboid; laterally, a single facet for the fifth metatarsal; and
medially, an oval facet for the third metatarsal. The latter is sometimes
in the shaft and the other in the base (unlike the other metatarsals, in
divided by a ridge, in which case the proximal part articulates with the
which the secondary ossification centre is distal). They appear during
lateral cuneiform.
the tenth week of prenatal life and the third year of life, respectively
(see Fig. 84.7,) and fuse between the seventeenth and twentieth years.
Muscle attachments The lateral head of the third dorsal and
There may be a third centre in the first metatarsal head.
second plantar interossei are attached to the medial surface. The medial
Second metatarsal head of the fourth dorsal interosseous is attached to the lateral surface.


The second metatarsal is the longest (see Figs 84.5, 84.11). Its cuneiform Vascular supply The blood supply of the fourth metatarsal is the
base bears four articular facets. The proximal one, concave and triangu
same as that of the second and third metatarsals, described above.
lar, is for the intermediate cuneiform. The dorsomedial one, for the
medial cuneiform, is variable in size and usually continuous with that Innervation The fourth metatarsal is innervated by the deep fibular
for the intermediate cuneiform. Two lateral facets, dorsal and plantar,
and lateral plantar nerves.
are separated by nonarticular bone, each divided by a ridge into distal
demifacets, which articulate with the third metatarsal base, and a proxi Ossification There are two centres of ossification, one in the shaft
mal pair (sometimes continuous) for the lateral cuneiform. The areas and one distally in the metatarsal head (see Fig. 84.7). Ossification of
of these facets vary, particularly the plantar facet, which may be absent. the shaft starts during the ninth prenatal week and ossification of the
An oval pressure facet, caused by contact with the first metatarsal, may metatarsal head commences between the third and fourth years; fusion
appear on the medial side of the base, plantar to that for the medial occurs between the seventeenth and twentieth years.
cuneiform. Because of its length, its steep inclination, and the position
of its base recessed in the tarsometatarsal joint, it is at risk of stress Fifth metatarsal
overload; perhaps this is why it is a common site for stress fractures The fifth metatarsal has a tuberosity on the lateral side of its base (see
(particularly in athletes) and an avascular phenomenon in its head Figs 84.5, 84.11). The base articulates proximally with the cuboid by a
(Freiberg’s infraction). The second metatarsal head is affected in 68% triangular, oblique surface, and medially with the fourth metatarsal. The


of cases, the third metatarsal head in 27% of cases, and the fourth tuberosity can be seen and palpated midway along the lateral border
metatarsal head in 3% of cases. Freiberg’s disease is the only osteochon of the foot; in acute inversion it may be fractured. The metaphysial–
drosis more common in females and occurs at a ratio of 5 : 1 with peak diaphysial junction of the fifth metatarsal base is prone to traumatic or
age of onset between 11 and 17 years (Carmont et al 2009, Cerrato stress fractures. It is believed that fractures at this level damage the
2011). nutrient artery and the extraosseous arterial plexus, resulting in com
promised vascularity of the fracture site, consequent poor fracture
Muscle attachments The lateral head of the first dorsal interos healing and nonunion that often requires surgical fixation.
seous and the medial head of the second are attached to the medial
and lateral surfaces of the shaft, respectively. Muscle attachments The tendon of fibularis tertius is attached to
the medial part of the dorsal surface and medial border of the shaft,
Vascular supply The blood supply of the second, third and fourth and that of fibularis brevis to the dorsal surface of the tuberosity. A
metatarsals follows the same pattern as that described for the first meta strong band of the plantar aponeurosis, sometimes containing muscle,
tarsal, i.e. the bones are all supplied by branches of the dorsal and connects the apex of the tuberosity to the lateral process of the calcaneal
plantar metatarsal arteries. The nutrient artery enters the diaphysis on tuberosity. It is this attachment, and not that of fibularis brevis, that is
its lateral side near the metatarsal base. A constant plantar vessel sup responsible for avulsion fractures of the tuberosity. The tendon of
plies the heads of the metatarsals. abductor digiti minimi grooves the plantar surface of the base and flexor
digiti minimi brevis is attached here. The lateral heads of the fourth
Innervation The second metatarsal is innervated by branches of the dorsal and the third plantar interossei are attached to the medial side


deep fibular and branches of the medial plantar nerve. of the shaft.
Ossification There are two centres of ossification, one in the shaft Vascular supply The fifth metatarsal is supplied by dorsal and
and one distally in the metatarsal head (see Fig. 84.7). Ossification of plantar metatarsal arteries and an inconstant fibular marginal artery.
the shaft starts during the ninth prenatal week and ossification of the The nutrient artery enters the diaphysis proximally and medially.


AnklE And fooT
1430
9
noITCES
Innervation The fifth metatarsal is innervated by branches from the 84.5). On occasion, there are only two phalanges in the little toe and,
sural, superficial fibular and lateral plantar nerves. rarely, this is the case with the other toes. The phalanges of the toes are
much shorter than their counterparts in the hand, and their shafts,
Ossification There are three centres of ossification, one at the base especially those of the proximal set, are compressed from side to side.
in the region of the tuberosity (an apophysis), one in the shaft and one In the proximal phalanges, the compressed shaft is convex dorsally,
distally in the metatarsal head. Ossification of the shaft starts during with a plantar concavity. The base is concave for articulation with a
the tenth prenatal week and ossification of the metatarsal head starts metatarsal head, and the head is a trochlea for the middle phalanx.
between the third and fourth years (see Fig. 84.7). Fusion of the distal Middle phalanges are small and short, but broader than their proximal
and shaft centres occurs between the seventeenth and twentieth years; counterparts. Distal phalanges resemble those in the fingers, but are
the proximal apophysis fuses earlier. An os vesalianum pedis is a smaller and flatter. Each has a broad base for articulation with a middle
rare variant that should not be confused with the basal apophysis phalanx and an expanded distal end. A rough tuberosity on the plantar
(Fig. 84.12). aspect of the latter supports the pulp of the toe and provides a weight
bearing area.
PHALANGES OF THE FOOT
Muscle attachments Tendons of the long digital flexors and exten
sors are attached to the plantar and dorsal aspects of the bases of the
In general, the phalanges of the foot resemble those of the hand; there
distal phalanges of the lateral four toes. Flexor hallucis longus and
are two in the great toe, and three in each of the other toes (see Fig.
extensor hallucis longus are similarly attached to the great toe. The
bases of the middle phalanges receive the tendons of flexor digitorum


A Os intercuneiforme brevis and extensor digitorum brevis. The proximal phalanges of the
Os talonaviculare dorsale second, third, fourth and fifth toes each receive a lumbrical on their
medial side; those of the second, third and fourth toes also receive an
Os trigonum
interosseous muscle on both sides. For further details of muscular,
capsular and ligamentous arrangements in the toes, refer to Figure 84.5.
The terminal phalanx of the great toe normally shows a small degree
of abduction, as may the proximal phalanx. This is presumed to be
unrelated to footwear because this degree of deviation has also been
observed in fetal specimens.
Vascular supply The proximal phalanges receive most of their blood
Os sustentaculi Pars peronea metatarsalis I supply from the dorsal digital arteries. The middle phalanges are sup
Os tibiale externum Medial sesamoid plied by plantar and dorsal digital arteries. The distal phalanges receive
their supply mainly from plantar digital arteries.
Interphalangeal sesamoid
Innervation The phalanges are innervated by the plantar and dorsal
B Os talonaviculare dorsale Os calcaneus secundarius digital nerves.
Os intercuneiforme Os trigonum Ossification Phalanges are ossified from a primary centre for the
shaft and a basal epiphysis (see Fig. 84.7). Primary centres for the distal
Os intermetatarsalis I
phalanges appear between the ninth and twelfth prenatal weeks, and
somewhat later in the fifth digit. Primary centres for the proximal
phalanges appear between the eleventh and fifteenth weeks, and later
for the middle phalanges, but there is wide variation. Basal centres
appear between the second and eighth years (usually second or third
in the great toe), and union with the shaft occurs by the eighteenth year.
There is considerable variation in ossification and fusion dates.
Os vesalianum pedis Os peroneum
SESAMOID BONES
Most sesamoid bones are only a few millimetres in diameter and their
C Second toe sesamoids Third toe sesamoids
shape is variable. Some have a predictable location (see below), but
many others vary in terms of location and frequency of occurrence (see
Fourth toe sesamoid


Fig. 84.12). Some sesamoid bones ossify, whereas others remain carti
Interphalangeal sesamoid
laginous. Most sesamoid bones are embedded in tendons in close
Lateral (fibular) sesamoid proximity to joints. Their precise role is not understood; it is believed
that they may alter the direction of muscle pull, decrease friction and
Medial (tibial) sesamoid
Fifth toe sesamoids modify pressure.
Medial and lateral sesamoid bones of the
first metatarsophalangeal joint
The two constant sesamoid bones within the foot are those of the first
Pars peronea metatarsalis I metatarsophalangeal articulation. The medial (tibial) sesamoid bone is
generally larger than the lateral (fibular) sesamoid bone and lies slightly
Sesamoid of tibialis posterior more distally. During dorsiflexion of the great toe, the sesamoid bones
Os vesalianum pedis
Os tibiale externum lie below the first metatarsal head, offering protection to the otherwise
(Os naviculare accessorium) Os peroneum exposed plantar aspect of the first metatarsal head. The medial sesamoid
is approximately 10 mm wide and 14 mm long, and the lateral sesam
Os cuboides secundarius oid is usually smaller (approximately 8 mm wide and 10 mm long);
the overall sizes of the sesamoid bones vary considerably.
The sesamoid bones are embedded within the double tendon of
flexor hallucis brevis and articulate on their dorsal surfaces with the
plantar facets of the first metatarsal head. They are separated by the
crista or intersesamoidal ridge, which provides stability to the sesamoid
Sesamoid bones
bone complex. (This ridge can be eroded to the point of obliteration
Accessory bones in severe cases of hallux valgus.) The sesamoid bones are connected to
the plantar base of the proximal phalanx through the plantar plate,
Fig. 84.12 Sites of sesamoid and accessory bones found in the left foot. which is an extension of the tendon of flexor hallucis brevis. A thin


A, Medial aspect. B, Lateral aspect. C, Plantar aspect. layer of the tendon of flexor hallucis brevis covers the plantar surface


Joints
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RETPAHC
of each sesamoid, whereas the dorsal or superior surface is covered by Articulating surfaces Articular surfaces are covered by hyaline car
hyaline cartilage. The sesamoid bones are suspended by a slinglike tilage. The talar trochlear surface, which is convex sagittally and gently
mechanism made up of the collateral ligaments of the first metatarso concave transversely, is wider anteriorly; the distal tibial articular surface
phalangeal joint and the sesamoid ligaments on either side of the is reciprocally curved. The talar articular surface for the medial malleo
joint. The plantar aponeurosis also has an attachment to the sesamoid lus is a proximal area on the medial talar surface, and is fairly flat,
bones. commashaped and deeper anteriorly. The larger lateral talar articular
Approximately 30% of these sesamoid bones are bipartite. The me surface is triangular and vertically concave, while the articular surface
dial is much more commonly affected and may have two, three or four on the lateral malleolus is reciprocally curved. Posteriorly, the edge
parts, but the fibular sesamoid rarely has more than two. The condition between the trochlear and fibular articular surfaces of the talus is bevel
may be bilateral. The sesamoid bones may be congenitally absent. led to a narrow, flat triangular area that articulates with the inferior
transverse tibiofibular ligament (Fig. 84.13A); all surfaces are contigu
Muscle attachments The medial sesamoid bone receives an attach ous. The bones are held together by a fibrous capsule, and by medial
ment from abductor hallucis, which medially stabilizes the sesamoid collateral (deltoid), anterior and posterior talofibular and calcaneofibu
complex. The lateral sesamoid receives some fibres from the tendon of lar ligaments.
adductor hallucis and this provides lateral stabilization. The medial and
lateral sesamoid bones are connected by the intersesamoid ligament,
Fibrous capsule Around the joint, the fibrous capsule is thin in front
which forms the floor of the tendinous canal for the tendon of flexor
and behind. It is attached proximally to the borders of the tibial and


hallucis longus.
malleolar articular surfaces, and distally to the talus near the margins
Vascular supply There are three patterns of blood supply to the of its trochlear surface, except anteriorly where it reaches the dorsum
of the talar neck. The capsule is strengthened by strong collateral liga
sesamoid bones. In 50% of cases, the arterial supply is derived from the
ments. Its posterior part consists mainly of transverse fibres. It blends
medial plantar artery and the deep plantar arch; in 25% of cases, it is
with the inferior transverse ligament and is thickened laterally where it
predominantly from the deep plantar arch; and in 25% of cases, it is
reaches the fibular malleolar fossa.
from the medial plantar artery alone. The major arterial blood supply
to the sesamoid bones enters from the proximal and plantar aspects,
and only a minor contribution enters through their distal poles. Ligaments The ligaments of the ankle joint are the medial and lateral
collateral ligaments.
Innervation The medial and lateral sesamoid bones are innervated by
the plantar digital nerves. Medial collateral ligament (deltoid ligament) The medial collateral
ligament (deltoid ligament) is a strong, triangular band, attached to the
Ossification The ossification centres of the sesamoid bones can be apex and the anterior and posterior borders of the medial malleolus
multiple or single. (Panchani et al 2014; Fig. 84.13B). Of its superficial fibres, anterior
Other sesamoid and accessory bones (tibionavicular) fibres pass anteriorly to the navicular tuberosity, behind
which they blend with the medial margin of the plantar calcaneona
Accessory or inconstant sesamoid bones may occur under any weight
vicular ligament; intermediate (tibiocalcaneal) fibres descend almost
bearing surface of the foot but are most common under the second to
vertically to the entire length of the sustentaculum tali; posterior (super
fifth metatarsal heads. They are extremely variable in size and their
ficial posterior tibiotalar) fibres pass posterolaterally to the medial side
incidence is difficult to determine.
of the talus and its medial tubercle; and additional fibres posterior to


A true sesamoid bone occasionally occurs in the tendon of tibialis
the sustentaculum tali have been reported (Panchani et al 2014). Of its
posterior. It lies on the plantar aspect of the navicular tuberosity within
deep fibres, anterior (anterior tibiotalar) fibres pass from the medial
the tendon at the level of the inferior border of the calcaneonavicular
malleolus to the nonarticular part of the medial talar surface; interme
ligament (see above, accessory naviculars). Very rarely, a sesamoid bone
diate fibres deep to the tibiocalcaneal ligament descend almost verti
is found within the tendon of tibialis anterior near its insertion at the
cally to the entire length of the sustentaculum tali; posterior (deep
level of the anteroinferior corner of the medial cuneiform, where there
posterior tibiotalar) fibres pass posterolaterally to the medial side of the
is an articular facet. An os peroneum is a sesamoid bone within the
talus and its medial tubercle; and additional fibres may pass to the
tendon of fibularis longus that articulates with the lateral surface of the
spring ligament (Pankovich and Shivaram 1979, Milner and Soames
calcaneus, the calcaneocuboid joint or, more frequently, the plantar
1998, Boss and Hintermann 2002). The tendons of tibialis posterior
aspect of the cuboid where there is an articular facet. The bone is situ
and flexor digitorum longus cross the ligament. The medial collateral
ated where the tendon of fibularis longus angles around the plantar
ligament of the ankle is rarely injured alone: tears are commonly associ
aspect of the lateral border of the cuboid and is usually cartilaginous.
ated with a fracture of the distal fibula. Chronic instability is rare.
The frequency of the os peroneum has been reported to be as low as
4.7% and as high as 90% (Coskun et al 2009, Oyedele et al 2006,
Lateral collateral ligament The lateral collateral ligament has three
Muehleman et al 2009).
discrete parts. The anterior talofibular ligament extends anteromedially


from the anterior margin of the lateral malleolus to the talus, attached
JOINTS anterior to its lateral articular facet and to the lateral aspect of its neck
(Fig. 84.13C). The posterior talofibular ligament runs almost horizon
ANKLE (TALOCRURAL) JOINT tally from the distal part of the lateral malleolar fossa to the lateral
tubercle of the posterior talar process (see Fig. 84.13A); a ‘tibial slip’ of
fibres, also known as transverse fibres of the posterior talofibular liga
The ankle joint is a hinge joint, approximately uniaxial. The lower end
ment, connects it to the medial malleolus. The calcaneofibular liga
of the tibia and its medial malleolus, together with the lateral malleolus
ment, a long cord, runs from a depression anterior to the apex of the
of the fibula and inferior transverse tibiofibular ligament, form a deep
lateral malleolus to a tubercle on the lateral calcaneal surface and is
recess (‘mortise’) for the body of the talus. Although it appears to be a
crossed by the tendons of fibularis longus and brevis (see Fig. 84.13A,C).
simple hinge, its axis of rotation is dynamic, shifting during dorsiflexion
The lateral ligament complex – more specifically, the anterior talofibular
and plantar flexion. Starting from the plantigrade position, the normal
ligament – is injured most commonly with inversion sprains; the pos
range of dorsiflexion is 10° when the knee is straight, and 30° with the
terior talofibular ligament is almost always spared. Although the result
knee flexed (when the calcaneal tendon will be relaxed). The range of
ing increased laxity is tolerated in most cases, some require surgical
normal plantar flexion is 30°. (The values of these ranges are all approx
reconstruction.
imate.) Dorsiflexion results in the joint adopting the ‘closepacked’
position, with maximal congruence and ligamentous tension; from this
position, all major thrusting movements are exerted, in walking, Synovial membrane The joint is lined by a synovial membrane,


running and jumping. The malleoli grip the talus, and even in relaxa which projects into the inferior tibiofibular joint.
tion, no appreciable lateral movement can occur without stretch of the
inferior tibiofibular syndesmosis. The superior talar surface is broader Vascular supply and lymphatic drainage The ankle joint is
in front, and in dorsiflexion, the malleolar gap is increased by slight supplied by malleolar branches of the anterior and posterior tibial and
lateral rotation of the fibula, by ‘give’ at the inferior tibiofibular syn fibular arteries. Lymphatic drainage is via vessels accompanying the
desmosis and gliding at the superior tibiofibular joint. Normal ankles arteries and via the long and small saphenous veins, superficially.
show valgus inclination at birth. The morphology changes in the first
few years of life and the ankle reaches the adult position by the age of Innervation The ankle joint is innervated by branches from the
three years (Nakai et al 2000). deep fibular, saphenous, sural and tibial nerves (or medial and lateral


AnklE And fooT
1432
9
noITCES
A
Posterior tibiofibular Tibial slip of posterior talofibular ligament
ligament
Groove for tibialis posterior
Inferior transverse
tibiofibular ligament
Medial malleolus
C Anterior tibiofibular ligament
Posterior tibiotalar
Parts of
Lateral malleolus deltoid ligament Posterior tibiofibular
Tibiocalcaneal
ligament
Posterior Anterior talofibular ligament
talofibular ligament Posterior process of talus
Talonavicular ligament
Posterior talofibular
Groove for flexor ligament
Calcaneofibular ligament hallucis longus Dorsal cuneonavicular
ligaments
Dorsal cuneocuboid Calcaneofibular
ligament ligament
Dorsal tarsometatarsal
ligaments
Dorsal intermetatarsal
ligaments
B
Posterior
tibiotalar Dorsal tarsometatarsal Bifurcate Cervical ligament
Sup de er lf ti oc ii da l lip ga ar mts e o nf t Tibio- Talonavicular ligament ligaments ligament Long plantar ligament
calcaneal
Dorsal cuneonavicular ligaments Dorsal cuboidonavicular ligament
Tibio-
navicular
Sustentaculum tali
Dorsal
Ligaments of first
tarsometatarsal joint
Plantar
First metatarsal
Plantar calcaneonavicular Long plantar Tuberosity of navicular
(spring) ligament ligament
Fig. 84.13 The left ankle and tarsal joints. A, Posterior aspect. B, Medial aspect. C, Lateral aspect.
plantar nerves, depending on the level of division of the tibial nerve). Factors maintaining stability Passive stability is conferred upon
Occasionally, the superficial fibular nerve also supplies the ankle the ankle mainly by the medial and lateral ligament complexes, the
joint. distal tibiofibular ligaments, the tendons crossing the joint, the bony
For a comprehensive account of the innervation of the ankle joint contours and the capsular attachments. Gravity, muscle action and
(and other foot joints), see Gardner and Gray (1968) and Sarrafian ground reaction forces provide dynamic stability. Stability requires the


(2011). continuous action of soleus assisted by gastrocnemius; it increases
when leaning forwards, and decreases when leaning backwards. If back
Relations Anteriorly, from medial to lateral, are tibialis anterior, ward sway takes the projection of the centre of gravity (‘weight line’)
extensor hallucis longus, the anterior tibial vessels, deep fibular nerve, posterior to the transverse axes of the ankle joints, the muscles that
extensor digitorum longus and fibularis tertius; posteromedially, from plantar flex and dorsiflex relax and contract, respectively.
medial to lateral, are tibialis posterior, flexor digitorum longus, the Failure of the fibular muscles can lead progressively to varus instabil
posterior tibial vessels, tibial nerve and flexor hallucis longus; in the ity of the ankle, whereas longstanding failure of the tendon of tibialis
groove behind the lateral malleolus are the tendons of fibularis longus posterior, posterior tibial tendon dysfunction, can result in valgus insta
and brevis. The tendon of fibularis brevis lies anterior to the tendon of bility of the ankle and particularly a planovalgus foot deformity com
fibularis longus at this level (Fig. 84.14). The long saphenous vein and monly referred to as adult acquired flatfoot deformity.
saphenous nerve cross the ankle joint medial to the tendon of tibialis
anterior and anterior to the medial malleolus, the nerve lying posterior Posterior tibial tendon dysfunction
to the vein.
All of the above structures are at risk during surgery on the ankle; Available with the Gray’s Anatomy e-book
the main structures at risk are the neurovascular structures located
anteriorly and posteromedially. Branches of the superficial fibular nerve Muscles producing movement Dorsiflexion is produced by tibi
are at risk of injury on the anterolateral aspect of the ankle, particularly alis anterior, assisted by extensors digitorum longus and hallucis longus,
during ankle arthroscopy. and fibularis tertius. Plantar flexion is produced by gastrocnemius and


48
RETPAHC
Ankle and foot
The aetiology of posterior tibial tendon dysfunction is complex. The
incidence is greater in obese, middleaged women. There are multiple
contributory factors such as diabetes mellitus and hypertension, which
are further complicated by steroid exposure or previous trauma or
surgery in the region of the tendon of tibialis posterior. There is often
a progressive disruption not only of this tendon, but also of multiple
ligamentous complexes such as the spring ligament and those support
ing the naviculocuneiform and tarsometatarsal ligaments. This leads to
a marked collapse of the medial longitudinal arch, which can be staged
using the original Johnson and Strom (1989) classification system and
that of Myerson (1997). Along with the varying methods used to diag
nose posterior tibial tendon dysfunction, a clinically important test is
the single heelrise test used in the initial stages of adult acquired flat
foot deformity (Deland 2008, Gluck et al 2010, Durrant et al 2011).
1432.e1


Joints
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RETPAHC
Superficial fibular nerves Dorsalis pedis artery Extensor hallucis longus inferior transverse ligament, a thick band of yellow fibres, which crosses
from the proximal end of the lateral malleolar fossa to the posterior
Tibialis anterior
Extensor digitorum longus and border of the tibial articular surface almost to the medial malleolus.
fibularis tertius in fibrous loop of Long saphenous The ligament projects distal to the bones, in contact with the talus. Its
inferior extensor retinaculum vein colour reflects its content of yellow elastic fibres.
Deep fibular nerve
Saphenous Synovial membrane The synovial membrane of the ankle joint
nerve projects into the distal 4 mm or so of the inferior tibiofibular joint.
Talus
Vascular supply and lymphatic drainage The inferior tibiofibu
lar joint is supplied by the perforating branch of the fibular artery and
Medial lateral malleolar branches of the anterior and posterior tibial arteries.
Lateral malleolus
Lymphatic drainage is via vessels corresponding to the arteries, and via
malleolus
vessels that accompany the great and small saphenous veins.
Posterior
talofibular Tibialis posterior Innervation The inferior tibiofibular joint is innervated by branches
ligament from the deep fibular and sural nerves.
Flexor digitorum
Fibularis longus longus
and fibularis brevis Tibial nerve Relations No significant structures pass anterior to the anterior aspect
of the inferior tibiofibular joint but the superficial fibular nerve is at
Sural nerve Posterior tibial artery risk during surgery to this area. Posteriorly, the fibular artery passes over
Small saphenous vein the posterior tibiofibular ligament and is at risk in the posterolateral
approach to the fibula.
Flexor hallucis longus
Fat
Factors maintaining stability Stability is maintained in part by
the bone contours, but mainly by the dense anterior and posterior
tibiofibular and the interosseous ligaments.
Calcaneal tendon
Muscles producing movement No muscles act on the inferior
tibiofibular joint, which moves only slightly. Because of the varying


slope of the lateral surface of the body of the talus, the fibula undergoes
Fig. 84.14 A transverse section through the lower part of the left ankle a small degree of lateral rotation during dorsiflexion at the ankle, and
joint, superior aspect. this results in slight widening of the interval between the bones. Testing
for a significant disruption of this joint is usually carried out with the
soleus, assisted by plantaris, tibialis posterior, flexor hallucis longus and patient under anaesthesia and involves applying a lateral rotation and
flexor digitorum longus. abduction force, looking for abnormal widening of the syndesmosis.
Another helpful clinical test for evaluating a syndesmotic injury is the
Ankle fractures Ankle fractures are common and of importance Hopkinson squeeze test. This test is carried out by compressing the
because failure to achieve accurate anatomical alignment in the treat fibula to the tibia at the midpoint of the leg. An injured syndesmosis
ment of ankle fractures often results in significant longterm morbidity. will result in pain in the area of the inferior tibiofibular joint (Scheyerer
Except for very simple and nondisplaced fractures, most ankle fractures et al 2011, Hopkinson et al 1990). Excessive anterior/posterior glide of
are associated with a ligamentous injury. The direction and nature of the fibula relative to the tibia also indicates a disruption of the joint.
forces applied to the ankle correlate with the fracture pattern and con
comitant ligament injury.
TARSAL JOINTS
INFERIOR TIBIOFIBULAR JOINT Talocalcaneal joint
The inferior tibiofibular joint is usually considered a syndesmosis. It
Anterior and posterior articulations between the calcaneus and talus
consists of the anterior and posterior tibiofibular and interosseous
form a functional unit termed the talocalcaneal or subtalar joint (see
ligaments.
Fig. 84.16). The posterior articulation is referred to as the talocalcaneal
Articulating surfaces The distal tibiofibular joint is between the joint and the anterior articulation is regarded as part of the talocalca
neonavicular joint. The talocalcaneal joint is a modified multiaxial joint
rough, medial convex surface on the distal end of the fibula and the


and its permitted movements are considered together with those at
rough concave surface of the fibular notch of the tibia. These surfaces
other tarsal joints. The bones are connected by a fibrous capsule, and
are separated distally for approximately 4 mm by a synovial prolon
by lateral, medial, interosseous talocalcaneal and cervical ligaments.
gation from the ankle joint, and may be covered by articular cartilage
in their lowest parts.
Articulating surfaces The subtalar joint proper involves the concave
Fibrous capsule The inferior tibiofibular joint does not have a posterior calcaneal facet on the posterior part of the inferior surface of
the talus and the convex posterior facet on the superior surface of the
capsule.
calcaneus (Fig. 84.15).
Ligaments The ligaments of the inferior tibiofibular joint are the
anterior, interosseous and posterior ligaments. Fibrous capsule The fibrous capsule envelops the joint; its fibres are
short and attached to its articular margins.
Anterior tibiofibular ligament The anterior tibiofibular ligament is a
flat band, which descends laterally between the adjacent margins of the Ligaments The ligaments of the talocalcaneal joint are the lateral,
tibia and fibula, anterior to the syndesmosis (see Fig. 84.13C). Bassett’s medial and interosseous talocalcaneal ligaments and the cervical
ligament is a variant that presents as a lowlying slip of the ligament, ligament.
which is inserted so far distally on the fibula that it may cause irritation
of the lateral aspect of the talus; it is amenable to arthroscopic removal Lateral talocalcaneal ligament The lateral talocalcaneal ligament is a
(Subhas et al 2008). short flat fasciculus that descends obliquely and runs inferoposteriorly
from the lateral process of the talus to the lateral calcaneal surface and
Interosseous tibiofibular ligament The interosseous tibiofibular liga is attached anterosuperior to the calcaneofibular ligament.
ment is continuous with the interosseous membrane and contains
many short bands between the rough adjacent tibial and fibular sur Medial talocalcaneal ligament The medial talocalcaneal ligament con


faces; it is the strongest union between the bones. nects the medial tubercle of the talus to the posterior aspect of the
sustentaculum tali and adjacent medial surface of the calcaneus. Its
Posterior tibiofibular ligament The posterior tibiofibular ligament is fibres blend with the medial (deltoid) ligament of the ankle joint; the
stronger than the anterior, and is placed similarly on the posterior most posterior fibres line the groove for flexor hallucis longus between
aspect of the syndesmosis (see Fig. 84.13A). Its distal, deep part is the the talus and calcaneus.


AnklE And fooT
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noITCES
A Dorsal tarsometatarsal ligaments
First metatarsal
Second metatarsal
Fourth metatarsal
Fifth metatarsal
Dorsal intercuneiform
ligaments
Tuberosity of fifth metatarsal Dorsal cuneonavicular
ligaments
Dorsal cuneocuboid ligament
Cuboid
Calcaneonavicular
ligament Navicular
Bifurcate ligament
Calcaneocuboid
Plantar calcaneonavicular
ligament
ligament
Tendon of fibularis brevis
Middle talar articular surface B Anterior talofibular
ligament
Anterior talar articular surface Interosseus talocalcaneal
ligament Interosseous
Posterior talar articular talocalcaneal
surface ligament
Calcaneus
Deltoid
ligament
Calcaneofibular
ligament
Calcaneal tuberosity
Fig. 84.15 A, Disarticulated talocalcaneal and talocalcaneonavicular joints, seen from above. B, A disarticulated talus (seen from below). (With
permission from Waschke J, Paulsen F (eds), Sobotta Atlas of Human Anatomy, 15th ed, Elsevier, Urban & Fischer. Copyright 2013.)
Fig. 84.16 A coronal section through the
Tibia left ankle and talocalcaneal joint (seen
Ankle joint from behind). (With permission from
Tibiofibular syndesmosis Tibia, medial malleolus Waschke J, Paulsen F (eds), Sobotta Atlas
(inferior tibiofibular joint) of Human Anatomy, 15th ed, Elsevier,
Urban & Fischer. Copyright 2013.)
Medial collateral ligament
(deltoid ligament),
Talus, body tibiocalcaneal part
Fibula, lateral malleolus
Tendon of tibialis posterior
Tendon of flexor digitorum longus
Calcaneofibular ligament
Subtalar joint (talocalcaneal joint) Flexor retinaculum
Subtalar joint (talocalcaneal joint)
Tendon of fibularis brevis Interosseus talocalcaneal ligament
Medial plantar nerve and vessels


Tendon of fibularis longus
Abductor hallucis
Calcaneus Flexor accessorius
Abductor digiti minimi Lateral plantar nerve
Plantar aponeurosis
Flexor digitorum brevis
Interosseous talocalcaneal ligament The interosseous talocalcaneal medial to the attachment of extensor digitorum brevis, from where it
ligament is a broad, flat, bilaminar transverse band in the tarsal sinus ascends medially to an inferolateral tubercle on the talar neck (Barclay
(see Fig. 84.15A; Fig. 84.16). It descends obliquely and laterally from Smith 1896). It is considered to be taut in inversion of the foot.
the sulcus tali to the calcaneal sulcus. The posterior lamina of the liga
ment is associated with the talocalcaneal joint, and the anterior lamina Synovial membrane The synovial cavity of the talocalcaneal joint
with the talocalcaneonavicular joint. Its medial fibres are taut in ever is usually quite separate and does not communicate with those of other
sion of the foot. tarsal joints. However, direct communication with the ankle joint has
been observed in rare instances.
Posterior talocalcaneal ligament The posterior talocalcaneal ligament
is attached to the plantar border of the posterior process (posterolateral Innervation The talocalcaneal joint is innervated by branches of the
tubercle) of the body of the talus. tibial, medial plantar and sural nerves.
Cervical ligament The cervical ligament is just lateral to the tarsal sinus Relations Posteromedially, in the region of the posterior aspect of
and attached to the superior calcaneal surface (see Fig. 84.13C). It is the talocalcaneal joint, and viewed from anterior to posterior, veins on


Joints
1435
48
RETPAHC
either side of the posterior tibial artery, the tibial nerve and the tendon
of flexor hallucis longus are seen. These neurovascular structures are at
risk in posteromedial approaches to the ankle and talocalcaneal joints.
On the lateral side, the tendon of fibularis brevis lies anterior to the
tendon of fibularis longus, both passing behind the lateral malleolus
in proximity to the talocalcaneal joint. The sural nerve lies just posterior
to the tendons of the fibularis longus and brevis.
Factors maintaining stability Stability is conferred by the bony
Collateral ligaments
contours of the hindfoot plus the abovementioned ligaments; it is not
Plantar ligaments
known which ligaments provide the most stability. An additional liga
mentous restraint is provided by the calcaneofibular component of the
lateral ligament complex. The tendons crossing the articulation also add
stability. Deep transverse
metatarsal ligaments
Muscles producing movement Heel inversion is controlled by
tibialis anterior, tibialis posterior and the gastrocnemius–soleus First metatarsal, base
complex via the calcaneal tendon; the extrinsic flexors of the toes also
Plantar tarsometatarsal
contribute. Eversion of the foot results from the pull of fibularis longus, ligaments
brevis and tertius in addition to the extrinsic muscles that extend the
toes. Medial cuneiform
Plantar cuneonavicular Tuberosity of
Talocalcaneonavicular joint ligaments fifth metatarsal
Plantar cuboideonavicular
BarclaySmith provided an eloquent account of the talocalcaneonavicu ligament Groove for tendon
of fibularis longus
lar joint in 1896; for more recent studies, see Bonnel et al (2011) and
Bonnel et al (2013). In terms of function, and in clinical practice, it is Navicular, tuberosity Long plantar ligament
helpful to regard this complex joint as comprising two articulations, i.e. Plantar calcaneocuboid
the anterior part of the ‘subtalar’ joint and the talonavicular joint. It is Plantar calcaneonavicular ligament


a compound, multiaxial articulation. ligament
Calcaneofibular
ligament
Articulating surfaces The ovoid talar head is continuous with the Sustentaculum tali
Long plantar ligament
triplefaceted anterior area of its inferior surface. This part fits the con
cavity formed collectively by the posterior surface of the navicular, the
Medial collateral ligament
middle and anterior talar facets of the calcaneus, and the superior tibiocalcaneal part
fibrocartilaginous surface of the plantar calcaneonavicular ligament
(spring ligament). The bones are connected by a fibrous capsule and by Groove for tendon of
Calcaneal tuberosity
the talonavicular and plantar calcaneonavicular ligaments, and the cal flexor hallucis longus
caneonavicular part of the bifurcate ligament. Fig. 84.17 Ligaments on the plantar aspect of the left foot. (With
permission from Waschke J, Paulsen F (eds), Sobotta Atlas of Human
Fibrous capsule The fibrous capsule is poorly developed, except Anatomy, 15th ed, Elsevier, Urban & Fischer. Copyright 2013.)
posteriorly, where it is thick and blends with the anterior part of the
interosseous ligament filling the tarsal sinus.
Synovial membrane The talocalcaneonavicular joint is a synovial
Ligaments The ligaments of the talocalcaneonavicular joint are the joint whose cavity sometimes communicates with that of the talocalca
talonavicular and plantar calcaneonavicular (spring) ligaments. neal joint.
Talonavicular ligament The talonavicular ligament is a broad, thin Innervation The talocalcaneonavicular joint is innervated by the deep
band (see Fig. 84.13B,C). It connects the dorsal surfaces of the neck of fibular and medial plantar nerves.
the talus and the navicular, and is covered by extensor tendons. The
plantar calcaneonavicular ligament and the calcaneonavicular part of Relations On the medial side, from dorsal to plantar, lie the tendon
the bifurcate ligament (see Fig. 84.13C) are the plantar and lateral liga of tibialis posterior and the tendon of flexor digitorum longus above


ments of the joint, respectively. Although the calcaneus and navicular the sustentaculum tali, and the flexor hallucis longus tendon below. At
do not articulate directly, they are connected by the calcaneonavicular this point, flexor hallucis longus lies deep to the medial and lateral
part of the bifurcate ligament and the plantar calcaneonavicular plantar branches of the posterior tibial artery and tibial nerve. The latter
ligament. structures are at risk during medial approaches to the joint, e.g. resec
tion of talocalcaneal coalition. Dorsally from medial to lateral, lie the
Plantar calcaneonavicular (spring) ligament The plantar calcaneo tendons of tibialis anterior and extensor hallucis longus, the deep
navicular (spring) ligament is a broad, thick band connecting the ant fibular nerve and the dorsalis pedis artery, the muscle belly of extensor
erior margin of the sustentaculum tali to the plantar surface of the hallucis brevis passing medially and deep to the tendons of extensor
navicular (see Figs 84.13B, 84.15A; Fig. 84.17). It ties the calcaneus to digitorum longus and fibularis tertius. Structures at risk during the
the navicular below the head of the talus as part of its articular cavity dorsal approach to the talonavicular joint include the branches of the
and it maintains the medial longitudinal arch of the foot. According to superficial fibular nerve superficially and the dorsalis pedis artery and
Davis et al (1996), the spring ligament is made up of two distinct deep fibular nerve deep to the inferior extensor retinaculum.
structures: the superomedial calcaneonavicular portion and the inferior
calcaneonavicular portion. Factors maintaining stability Stability of the joint is due to a
The dorsal surface of the superomedial calcaneonavicular portion combination of factors: bony contours, the strong plantar calcaneo
has a triangular fibrocartilaginous facet on which part of the talar head navicular (spring) ligament, and the calcaneonavicular component of
rests (see Fig. 84.15A). Its plantar surface is supported medially by the the bifurcate ligament.
tendon of tibialis posterior and laterally by the tendons of flexors hal


lucis longus and digitorum longus; its medial border is blended with Muscles producing movement The muscles producing move
the anterior superficial fibres of the medial (deltoid) ligament. Jennings ment are as described above for the talocalcaneal joint.
and Christensen (2008) showed that transection of the spring ligament
leads to instability of the hindfoot, including talar head plantar flexion Calcaneocuboid joint
and adduction, consistent with pes planovalgus (adult acquired flat
foot) deformity. The inferior calcaneonavicular portion can become The calcaneocuboid joint is at the same level as the talonavicular joint
attenuated in adult acquired flatfoot deformity, and may require surgi and together they represent the transverse tarsal joint. It is a saddle
cal correction. (sellar) or biaxial joint with concavoconvex surfaces.


48
RETPAHC
Ankle and foot
The superomedial portion is the larger of the two, and originates
from the superomedial aspect of the sustentaculum tali and the anterior
edge of the anterior facet of the calcaneus. The inferior calcaneonavicu
lar portion originates from between the middle and anterior calcaneal
facets at the anterior portion of the sustentaculum tali. Both portions
insert on the inferior surface of the midnavicular, with the supero
medial portion inserting medial to the inferior portion.
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AnklE And fooT
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9
noITCES
Articulating surfaces The articular surfaces of the calcaneocuboid Relations Fibularis longus and abductor digiti minimi pass in prox
joint, which is 2 cm proximal to the tubercle on the fifth metatarsal imity to the joint, and the lateral plantar nerve passes medially. Extensor
base, are between the anterior (distal) surface of the calcaneus and the digitorum brevis overlies the lateral aspect of the joint. The sural nerve
posterior (proximal) surface of the cuboid. and the tendon of fibularis longus are at risk during approaches to an
os peroneum.
Fibrous capsule The fibrous capsule is thickened dorsally as the
dorsal calcaneocuboid ligament. The synovial cavity of this joint is Factors maintaining stability The calcaneocuboid joint only
separate, and does not communicate with those of other tarsal permits a small amount of movement; its stability reflects the bony
articulations. contours and strong ligaments described above.
Ligaments The ligaments of the calcaneocuboid joint are the bifur
Muscles producing movement Gliding occurs between the cal
cate, long plantar and plantar calcaneocuboid ligaments.
caneus and cuboid, with conjunct rotation on each other during inver
sion and eversion of the entire foot. The same muscles that act on the
Bifurcate ligament The bifurcate ligament (Chopart’s ligament) is a
talocalcaneal and talocalcaneonavicular joints bring about these
strong Yshaped band (see Fig. 84.13C). It is attached by its stem proxi
movements.
mally to the anterior part of the upper calcaneal surface, and distally it
divides into calcaneocuboid and calcaneonavicular parts. A separate
Naviculocuneiform joint
ligament, the lateral calcaneocuboid ligament, extends to the dorso
medial aspect of the cuboid, forming a main bond between the two
rows of tarsal bones; the (medial) calcaneonavicular ligament is The naviculocuneiform joint is a compound joint, often described as a