etrate the posterior sacrococcygeal ligament and enter the sacral canal.
The puncture of the ligament can usually be felt as the needle is
advanced. Once the canal is entered, the hub of the needle is lowered
so that the needle may be fed along the canal (see Fig. 45.2; Fig. 45.20). Fig. 45.20 Position of the needle in a caudal epidural injection.
If the needle is angled too obliquely, it will strike bone; if it is placed
too superficially, it will lie outside the canal and any fluid injected can
be felt subcutaneously.


SPinAl CoRd And SPinAl nERvES: gRoSS AnATomy
773.e4
5
noiTCES
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AJNR Am J Neuroradiol 29:619–31. and granulations. Neuroradiology 11:221–8.
Barson AJ 1970 The vertebral level of termination of the spinal cord during Kubik S, Müntener M 1969 [Topography of the spinal nerve roots. II. The
normal and abnormal development. J Anat 106:489–97. influence of the growth of the dural sac as well as of the curvatures and
Barson AJ, Sands J 1977 Regional and segmental characteristics of the of the movements of the vertebral column upon the course of spinal
human adult spinal cord. J Anat 123:797–803. nerve roots]. Acta anatomica 74:149–68. [Article in German.]
Boese CK, Lechler P 2013 Spinal cord injury without radiologic abnormali- Lee HM, Kim NH, Park CI 1990 Spinal cord injury caused by a stab wound–a
ties in adults: a systematic review. J Trauma Acute Care Surg 75: case report. Yonsei Med J 31:280–4.
320–30. Macdonald A, Chatrath P, Spector T, Ellis H 1999 Level of termination of
Boese CK, Nerlich M, Klein SM et al 2013 Early magnetic resonance imaging the spinal cord and the dural sac: a magnetic resonance study. Clin Anat
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rospective study. J Trauma Acute Care Surg 74:845–8. Malas MA, Salbacak A, Büyükmumcu M et al 2001 An investigation of the
Boon JM, Abrahams PH, Meiring JH et al 2004 Lumbar puncture: anatomi- conus medullaris termination level during the period of fetal develop-


cal review of a clinical skill. Clin Anat 17:544–53. ment to adulthood. Kaibogaku Zasshi 76:453–9.
Bösenberg AT, Gouws E 1995 Skin-epidural distance in children. Anaesthe- Neidre A, MacNab I 1983 Anomalies of the lumbosacral nerve roots. Review
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Broadbent CR, Maxwell WB, Ferrie R et al 2000 Ability of anaesthetists to Newell RL 1999 The spinal epidural space. Clin Anat (New York, NY) 12:
identify a marked lumbar interspace. Anaesthesia 55:1122–6. 375–9.
Carmichael S, Gloviczki P 1999 Anatomy of the blood supply to the Pang D, Wilberger JE Jr 1982 Tethered cord syndrome in adults. J Neurosurg
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compares their clinical presentation to children with similar pathology.
Crock H 1996 An Atlas of Vascular Anatomy of the Skeleton and Spinal
Cord. London: Martin Dunitz. Pouw MH, van Middendorp JJ, van Kampen A et al 2010 Diagnostic criteria
of traumatic central cord syndrome. Part 1: A systematic review of clini-
Dean NA, Mitchell BS 2002 Anatomic relation between the nuchal ligament
cal descriptors and scores. Spinal Cord 48:652–6.
(ligamentum nuchae) and the spinal dura mater in the craniocervical
region. Clin Anat (New York, NY) 15:182–5. Radcliff KE, Kepler CK, Delasotta LA et al 2011 Current management review
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Ditunno JF, Little JW, Tessler A 2004 Spinal shock revisited: a four-phase
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model. Spinal Cord 42:383–95.


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Neurosurg Focus 23:E7.


COMMENTARY
Minimally invasive surgical corridors
5.1
to the lumbar spine
Y Raja Rampersaud
As demonstrated in Ch. 43, the posterior spinal musculature consists morbidity resulting from iatrogenic muscle denervation (particularly
of multiple layers of muscles with fibres running in varying directions with exposure lateral to the facet joint), increased intramuscular pres-
and with varying segmental insertion points. Consequently, posterior sures, ischaemia and revascularization injury (Rampersaud et al 2006).
exposure of the spine does not traditionally follow expansile planes that Denervation and ischaemia can result from two possible mechanisms
avoid neurovascular structures over multiple spinal levels. Dependent that can occur independently or in combination: first, direct trauma to
on the degree of exposure required for a given procedure, conventional the segmental innervation (i.e. dorsal root branches) and vasculature;
posterior spinal approaches progressively release the posterior muscles and second, increased intramuscular pressure (i.e. focal compartment
from their bony attachments in a medial to lateral direction. This often syndrome) resulting from commonly used surgical retractors. These
requires a significant degree of muscle dissection and retraction (Fig. effects can lead to temporary or permanent paraspinal muscular
5.1.1a), particularly for common procedures such as the placement of atrophy, scarring, decreased extensor strength and endurance, as well as
spinal pedicle screw fixations that require access lateral to the facet pain.
joints. This type of exposure has been shown to cause significant muscle Minimal access surgery (MAS) approaches have been successfully
applied to a variety of anatomical areas, wherein the relevant target(s)
can be reliably accessed and manipulated within a defined anatomical
space or cavity with minimal patient morbidity. Due to wide variation
in the goals of spinal procedures and a variety of anatomical and surgi-
cal techniques and technological challenges, MAS approaches to the
spine have been limited to very specific indications and have not been
considered generalizable. However, in the last 10–15 years significant
progress has been made in MAS for the treatment of spinal disorders.
This is particularly so in relation to the lumbar spine, where the major-
ity of MAS spinal procedures are performed. Minimal access techniques
for spinal surgery have been enabled by the development of specialized
retractors, dissecting instruments and spinal implants that allow less


Spinous destructive and more reliable access to the spine by means of segmental
process transmuscular corridors. A detailed discussion of the anatomical and
technical aspects of current procedures is beyond the scope of this brief
commentary and only a general overview of the muscular corridors
utilized for MAS spine procedures is provided.
Utilizing modifications of the sacrospinalis-splitting approach intro-
duced by Wiltse several decades ago, transmuscular access to the spine
is typically gained by splitting a specific paraspinal muscle (Fig. 5.1.2)
in line with the fascicular bundles (i.e. intramuscular split) or by utiliz-
ing the natural cleavage plane between muscles (i.e. intermuscular split)
(Wiltse et al 1968). MAS spinal procedures are highly dependent on
the use of intraoperative imaging to allow accurate localization of the
A
skin and fascial incision. The segmental operative corridor is typically
created by the use of sequential muscle dilators over which a final retrac-
tor is docked on to the bony spinal anatomy. Alternatively, blunt dis-
section with a finger or a surgical instrument using a spreading technique
can be utilized to create the operative corridor. Current retractors are
typically tubular in shape (i.e. provide a ‘keyhole’ through the overlying
muscle) and come in varying diameters (14–30 mm) with fixed or
expandable aperture options (see Fig. 5.1.1b). For procedures such as
posterior decompression of the spinal canal and/or discectomy, an
intramuscular approach through the multifidus just paramedian to the
spinous process is typically applied (see Fig. 5.1.2a). Due to the seg-
mental nature and orientation of the multifidus fascicles, a corridor (via
the same or multiple skin incisions) is recommended for each segment
that requires intervention. For the placement of spinal instrumentation,
a more lateral paramedian intermuscular corridor is utilized that takes
advantage of the natural separation between multifidus and longis-
simus (see Fig. 5.1.2a). This plane provides direct access to the pars,
transverse processes and facet joints with minimal soft tissue dissection
and retraction. It also provides a less obstructed trajectory for pedicle
screw fixation along the long axis of the pedicle. If required, release of


B multifidus from the facet joint also enables access to the dorsal spinal
anatomy medial to the facet joint. The intermuscular corridor allows
for an easily extensile exposure over 2–3 levels if required. For access
Fig. 5.1.1 A, An intraoperative photograph demonstrating a typical
conventional midline spinal exposure for a one-level fusion (pedicle to the lateral spinal structures cranial to the L5–S1 level, a transpsoas
screw heads are visible at the lateral aspect of the exposure). Note the intramuscular plane is utilized (see Fig. 5.1.2b). Properly performed,
degree of muscle retraction from the midline (spinous process). B, An this approach gives safe access to the anterior two-thirds of the vertebral
intraoperative photograph of a minimal access surgery (MAS) spinal body; however, it does carry the risk of injury to the major vessels
tubular retractor (22 mm in diameter and 8 cm deep) placed in the anteriorly and to the lumbosacral plexus in the posterior aspect of the
e52 paramedian intermuscular plane for a one-level fusion. psoas (Goldstein et al 2014). At L5–S1 lateral MAS access is directly


Minimally invasive surgical corridors to the lumbar spine
e53
1.5
YRATNEMMOC
L4/5
L2/3 Lateral
A
B
Paramedian 1 Paramedian 2
Fig. 5.1.2 A, Axial magnetic resonance imaging (MRI) at the level of the L4–5 disc demonstrating the intramuscular corridor (paramedian 1) through the
multifidus portion of sacrospinalis. The line labelled paramedian 2 demonstrates the intermuscular plane between multifidus and longissimus.
Corresponding with the progressive narrowing of the bony spinal width from caudal to cranial, the intermuscular plane typically moves closer to the
midline at more cranial levels. B, The intermuscular plane is more obvious in less densely muscled individuals. At the L2–3 level, the line labelled lateral
demonstrates the transpsoas intramuscular corridor used for accessing the lateral aspect of the anterior spine above the L5–S1 level.
blocked by the ilium and also carries risk of injury to the common iliac inferior to traditional open spinal procedures; however, long-term supe-
vessels. riority has yet to be proven. These MAS techniques can carry a signifi-
The current literature comparing conventional open spinal proce- cant technical learning curve and associated increased cost. At present,
dures to MAS spinal procedures supports the reduction of acute peri- in the absence of compelling proof of superiority, MAS spinal proce-
operative morbidity, with most reports demonstrating reduced blood dures are to be considered an alternative technique for the surgical
loss, pain and length of hospital stay with MAS procedures (Goldstein management of spinal disorders when appropriate indications are met.
et al 2014, Arnold et al 2012). In addition, there also appears to be a They are by no means to be considered a ‘standard of care’ and require
reduction in the incidence of deep surgical site infection, most likely a weighing up of patient and surgeon preferences, as well as surgeon
due to the creation of minimal dead space with the MAS procedures. experience, on a case-by-base basis. Anecdotally, MAS spinal procedures
The overall long-term (more than 1–2 years post surgery) clinical and are welcomed by patients and provide significant patient and surgeon


patient-reported outcomes, such as pain and function, appear not to be satisfaction when properly executed.
REFERENCES
Arnold PM, Anderson KK, McGuire RA Jr 2012 The lateral transpsoas current concepts. Spine (Phila Pa 1976) 31(11 Suppl):S96–102; discus-
approach to the lumbar and thoracic spine: a review. Surg Neurol Int sion S104. Review.
3(Suppl 3):S198–215. Wiltse LL, Bateman JG, Hutchinson RH et al 1968 The paraspinal sacrospi-
Goldstein CL, Macwan K, Sundararajan K et al 2014 Comparative outcomes nalis-splitting approach to the lumbar spine. J Bone Joint Surg Am
of minimally invasive surgery for posterior lumbar fusion: a systematic 50:919–26.
review. Clin Orthop Relat Res 472:1727–37.
Rampersaud YR, Annand N, Dekutoski MB 2006 Use of minimally invasive
surgical techniques in the management of thoracolumbar trauma:


CHAPTER Pectoral girdle and upper limb: overview
46
and surface anatomy
The upper limb exhibits an exceptional range of movement, which Anterior view
permits such wide positioning of the hand that it acts as a powered,
Superior angle
mobile, sensory organ. This range is enabled by a number of factors.
C6 Clavicle
The thoracoscapular and glenohumeral joints are remarkably little con First rib Coracoid process
strained and the muscles that both stabilize and move them are power C7
Acromion
ful. The skin is mobile, especially in the front of the neck, the axilla, T1
across the joints, and on the dorsum of the hand. The deep fascial
planes and the synovial tubes permit excursion of muscles and tendons T2
against each other and adjacent structures, and the condensation of that Lesser tubercle
fascia around the neurovascular bundles segregates them and enhances Greater tubercle
gliding. The excursion of the main nerves relative to the skeleton is Intertubercular groove
increased by delicate vascular fascial adventitia and by gliding planes Surgical neck
within the nerve trunks.
Second rib
The innervation of the upper limb is complex and rich. There is a
Medial border
particular concentration of specialized sensory organelles in the wrist
Scapula
and hand, not only in the skin but also in the deep afferent system from
muscles, tendons and joints. The postganglionic sympathetic vaso Inferior angle
Deltoid tuberosity
motor and sudomotor nerves are especially dense in the palmar skin.
Lateral border
The basis of stereognosis, the ability to recognize the qualities of objects
and textures, is a combination of stimuli from skin, tendon, muscle and Sternum
Humerus
joints. Movement is vital; blindfolded patients cannot identify the
nature of an object if it is simply placed on the finger, but recognize it
immediately if allowed to create spatial and temporal patterns by
feeling the object or material between the moving finger and thumb.
Medial supracondylar ridge Lateral supracondylar ridge
BONES AND JOINTS Lateral epicondyle
Medial epicondyle
The bones of the upper limb include the scapula, clavicle, humerus, Trochlea Capitulum


radius and ulna (connected by the interosseous membrane along most
of their length), the eight bones forming the carpus, five metacarpals Coronoid process Head of radius
and fourteen phalanges (Figs 46.1–46.2). There are two phalanges in Tuberosity of ulna
the thumb and three in each finger. Tuberosity of radius
The thoracoscapular joint is the platform for function of the upper
limb; paralysis of either of the two great muscles, trapezius and serratus Anterior oblique line
anterior, is crippling. The limb is directly attached to the axial skeleton
by one bony articulation, the sternoclavicular joint. The glenohumeral
joint is shallow and little constrained, whereas the acromioclavicular
joint is a plane joint stabilized by strong ligaments. The range of move
ments provided by these joints and the muscles acting across them is
Ulna Radius
enormous. Arthrodesis of the thoracoscapular joint is effective in scap
ulohumeral dystrophy; it restores full elevation of the limb but protrac
tion and retraction is lost. A correctly performed glenohumeral
arthrodesis retains powerful adduction, protraction and medial rota
tion, but lateral rotation and most of elevation are lost. The elbow
includes a hinge between the humerus and ulna, and two pivot joints:
one between the humerus and radius, the other between the proximal Ulna, head
Ulna, styloid process
radius and ulna. This permits a range of about 150° of extension and
Radius, styloid process
flexion, and 180° of pronosupination in conjunction with the distal Carpal bones
radioulnar joint. The wrist complex allows a range of flexion and exten
sion of about 140°, supplemented by some 70° of adduction and
Metacarpal
abduction. The condylar metacarpophalangeal joint enables 120° of
flexion and extension, about 40° of abduction and adduction, and
Proximal phalanx
some rotation. Pronation and supination are unique to the primate
(First) Proximal
upper limb. The range of movement of the thumb ray, which rests on
Distal phalanx


the ‘saddle’ carpometacarpal joint, the qualities of the long muscles and Phalanges (Second) Middle
the thenar muscles acting on the ray and the skin of the web space, are
(Third) Distal
unique to humans.
SKIN AND FASCIA
Fig . 46 .1 The bones of the pectoral girdle and upper limb: anterior view .
The skin over the front of neck and posterior triangle is mobile and is
776 sustained by underlying platysma. Large flaps may be raised safely when


muscles
777
64
rETPaHC
Posterior view forearm is important in temperature homeostasis. The consequences of
First rib
scarring from burn or other injury, or badly placed incisions, are severe,
Second rib and nowhere more so than after a deep burn of the axilla.
Superior angle C6 The superficial fascia (see Chs 2 and 29) is generally thicker on the
Clavicle C7 dorsal aspect of the neck, shoulder, arm and forearm. Measurement of
Acromioclavicular joint its thickness in the arm provides a useful measure of obesity. This fascia
T1 is an important gliding plane between the skin and the underlying deep
T2 fascia. Nerves and vessels are at risk of entrapment or even rupture
where they perforate the deep fascia to ramify into the superficial fascia
and skin.
Greater tubercle
The deep fascia, intermuscular septa and the interosseous membrane
between the radius and ulna define discrete compartments that enable
gliding of segregated structures against one another. The medial and
Surgical neck
lateral intermuscular septa of the arm and the interosseous membrane
also provide wide areas for the attachment of muscles. The various
fascial compartments are relevant to the spread of infection and tumour,
and are especially important in ischaemia.
Deltoid tuberosity
The prevertebral fascia (see Fig. 29.4; p. 445) envelops the phrenic
nerve, scalene muscles, cervical primary rami, cervical sympathetic
Spiral groove Sternum chain, and subclavian and vertebral arteries. It projects below the clav
icle as the axillary sheath, enveloping the divisions and cords of the
brachial plexus with the axillary artery, and continues into the arm as
Humerus
the brachial sheath, surrounding the brachial artery with its venae
comitantes, the median nerve and the proximal part of radial and ulnar
nerves. The great muscles of the shoulder and axilla – deltoid, pectoralis
major and latissimus dorsi – are covered by deep fascia that winds
around their deep surfaces to blend with the deep fascia of the arm.
This latter is drawn upwards by suspensory condensations of fascia to
form the coneshaped axillary space. This arrangement is obvious to the


Lateral epicondyle Medial epicondyle reader who traces the anterior surface of pectoralis major with a finger,
then follows it round and deep, before thrusting the finger upwards as
far at least as the lateral part of the second rib.
Head of radius Olecranon
The deep fascia of the arm and forearm forms a sort of sleeve,
attached to the medial and lateral intermuscular septa in the arm, to
the periosteum of the medial and lateral epicondyles and olecranon at
Posterior oblique line
the elbow, and to the periosteum of the ulna and radius (Chs 48–49).
There are important condensations, such as the bicipital aponeurosis at
the elbow, and the flexor and extensor retinacula at the wrist, which are,
in turn, subdivided by septa. Discrete compartments with the forearm
separate the superficial muscles from the deep. The reader will note
Radius Ulna the relative mobility of the extensor muscles that traverse the elbow:
brachioradialis and the radial extensor muscles of the wrist form
the ‘mobile wad’, overlying the deeper compartment containing the
posterior interosseous nerve and vessels, supinator, the digital exten
sors, extensor carpi ulnaris and the long muscles acting on the thumb
ray. Three compartments are found in the anterior aspect of the forearm.
Dorsal radial tubercle Ulna, head The deep flexor compartment contains the anterior interosseous nerve
and vessels, flexor pollicis longus, flexor digitorum profundus and pro
Radius, styloid process Ulna, styloid process nator quadratus. The superficial compartment contains the radial artery,
Carpal bones pronator teres, flexor carpi radialis, palmaris longus and flexor digit
orum superficialis. The ulnar nerve and vessels pass in a separate sheath
Metacarpal close to the ulna. The anterior deep fascia of the forearm continues into
the hand as the palmar aponeurosis, from which a complex arrange
Proximal phalanx ment of septa forms the fibrous skeleton of the hand (see Fig. 50.7A).
(First) Proximal The range of excursion of the main nerves of the upper limb across fixed


points such as the first rib, the distal humerus and the distal radius is
(Second) Middle Phalanges
some 10–15 mm and is enabled by gliding between the adventitia and
(Third) Distal the epineurium. More movement occurs within the plane between the
epineurium and perineurium, and also within the perineurium itself
(Commentary 9.1).
Cutaneous innervation
Fig . 46 .2 The bones of the pectoral girdle and upper limb: posterior
view .
Bundles of nerves enter the skin deep in the dermis and course towards
the skin surface, giving off axons, nearly all unmyelinated, that inner
vate the associated end organs. The few myelinated axons terminate at
hair follicles, Meissner corpuscles and Merkel complexes (Ch. 7, Com
platysma is included with the skin. The postaxial skin of the posterior
mentary 1.3). The density of innervation of the epidermis is greatest in
aspect of the neck, shoulder, arm and forearm is thicker and hairy,
the proximal segment of the limb and there is little change between the
whereas the glabrous preaxial skin on the anterior surface of the arm
twentieth and eightieth years.
and forearm is thinner and more mobile. The situation is reversed in
the hand, where the thick palmar skin is firmly secured by a fibrous
skeleton to the palmar aponeurosis, whereas the dorsal skin is thinner
MUSCLES
and more mobile, especially across the joints. The characteristic furrows
or creases at the elbow, wrist and the interphalangeal joints represent
places of anchorage of the deep fascia. The hairy skin of the axilla is The sensorimotor cortex controls movements, not individual muscles.
especially mobile, permitting the extensive range of movement at the Reaching out to catch a flying object, such as a cricket ball, requires the
glenohumeral joint; it is rich in sweat glands and their sympathetic coordination and integrated action of every muscle group in the upper
nerves. The dense sympathetic innervation in the axilla, the hand and limb, and indeed beyond. This system of complex and refined muscle


PECTOral GIrdlE aNd UPPEr lImb: OvErvIEw aNd SUrfaCE aNaTOmy
778
6
NOITCES
patterning depends on the integrity of the somatic afferent and efferent Brachiocephalic trunk
pathways in the central nervous system. Right and left common carotid arteries
The muscles of the upper limb may be grouped according to their Right Arch of aorta
origin and the joints on which they act: (1) Muscles arising from the subclavian Vertebral artery
axial skeleton to act on the scapula include trapezius, levator scapulae, artery Costocervical trunk
the rhomboids and serratus anterior. (2) Muscles arising from the axial Inferior thyroid artery
skeleton to act on the glenohumeral joint include the sternal head of Transverse cervical artery
pectoralis major, pectoralis minor and latissimus dorsi. (3) Muscles Superficial cervical artery
passing between the scapula and the proximal humerus control the Deep branch of transverse cervical artery
glenohumeral joint. They include supra and infraspinatus, subscapu Left subclavian artery
laris, teres major and minor, and coracobrachialis. Deltoid and the
Axillary artery
clavicular head of pectoralis major also belong here, even though they
arise in part from the clavicle. (4) The main muscles controlling the Thoracoacromial axis
elbow include biceps and triceps; the long heads of both muscles Superior thoracic artery
traverse the glenohumeral joint to insert on the scapula. (5) The main
Posterior and anterior
muscles controlling supination and pronation are biceps brachii and circumflex humeral arteries
supinator, pronator teres and pronator quadratus. (6) The radiocarpal
joint is controlled by extensors carpi radialis longus and brevis, extensor Subscapular artery
carpi ulnaris, flexors carpi ulnaris and radialis, and palmaris longus. Dorsal scapular artery
(7) The muscles acting on the thumb ray include the powerful flexor Lateral thoracic artery


pollicis longus, the much weaker abductor pollicis longus, and exten
sors pollicis longus and brevis. These last three are essential for thumb Brachial artery
function. The unopposed action of flexor pollicis longus leads to Suprascapular artery
the virtually useless thumb in palm posture. (8) The extension and Thyrocervical trunk
flexion of the metacarpophalangeal and interphalangeal joints of the Internal thoracic artery
fingers rest on coordinated activity in extensor digitorum, flexors digi
torum superficialis and profundus, and the interosseous and lumbrical Profunda brachii artery
Superior ulnar collateral artery
muscles. Extensor digitorum alone extends the metacarpophalangeal
Inferior ulnar collateral artery
joints; the long flexors alone flex the interphalangeal joints. The imbal
Radial collateral artery
ance caused by paralysis of the small muscles leads to ‘clawing’ deform
ity (see Fig. 46.27). (9) The small muscles of the hand may be considered Middle collateral artery
as those controlling the thumb ray and web space; adductor pollicis
lies deep to the first dorsal interosseous; abductor and flexor pollicis Anterior and posterior ulnar
brevis and opponens pollicis are superficial and form the ball of the recurrent arteries Radial recurrent artery
thumb. The interosseous muscles acting with the lumbricals flex, abduct
Interosseus recurrent artery
and adduct the metacarpophalangeal joints and, in conjunction with
Common interosseous artery
the long flexor and extensor muscles, enable full extension of the proxi
mal interphalangeal joints. Abductor and opponens digiti minimi and Posterior interosseous
flexor digiti minimi brevis form the hypothenar eminence and act on artery passing deep to
interosseous membrane
the little finger.
Many muscles act on more than one joint; thus, the long heads of
biceps and triceps flex and extend the glenohumeral joint, as well as Ulnar artery
the elbow. In addition, biceps brachii is a powerful supinator of the


forearm. Extensor carpi radialis longus not only extends the wrist, but Anterior interosseous artery
Radial artery
also is a powerful abductor of that joint and a flexor of the elbow. Flexor
carpi ulnaris is the most powerful muscle in the forearm; it contributes
to elbow flexion, flexes and adducts the wrist, and is active in all sus
tained movements of the wrist.
Certain muscles are functionally segregated, e.g. the anterior part of
deltoid is a powerful flexor of the glenohumeral joint, whereas the
posterior part is the most powerful extensor of that joint.
Deep palmar arch
Superficial palmar arch
VASCULAR SUPPLY AND LYMPHATIC DRAINAGE
The detailed regional descriptions of these systems are found in
Chapters 48, 49 and 50.
ARTERIES
The axial vessel is the subclavian artery, which arises from the brachio
Fig . 46 .3 The arteries of the upper limb .
cephalic trunk on the right and directly from the arch of the aorta on
the left (Fig. 46.3). The artery is described in three parts that are suc
cessively anterior, deep and lateral to scalenus anterior. The second and
third parts are in close relation to the primary ventral rami of C7, C8
and T1, and to the middle and lower trunks of the brachial plexus. The
subclavian artery becomes the axillary artery at the posterior margin of anterior interosseous artery, accompanied by the anterior interosseous
the first rib. The axillary artery is closely related to the divisions of the nerve, lies on the interosseous membrane in the deepest part of the
brachial plexus deep to the clavicle, and to the cords below it. It con deep flexor compartment. The posterior interosseous artery is separated
tinues deep to pectoralis minor and becomes the brachial artery at the from the membrane by the deep extensor muscles. The radial and ulnar
inferior margin of teres major. arteries remain in the flexor compartment of the forearm, the ulnar
The brachial artery is closely related to the median nerve; both move artery moving towards the ulnar nerve in the proximal quarter of the


from the medial side of the arm to the anterior aspect of the elbow, forearm; it is usually the dominant vessel for the hand. At the wrist, the
lying medial to the tendon of biceps brachii and deep to the bicipital radial artery passes dorsally and crosses the scaphoid and trapezium.
aponeurosis. The artery divides into the radial and ulnar arteries just Important branches from the main axial vessels form extensive anas
distal to the elbow. The ulnar artery is consistently the larger of the two. tomoses that provide a collateral circulation. For example, the collateral
The common interosseous artery arises close to its origin and subse circulation formed by branches of the thyrocervical trunk with the cir
quently divides into the anterior and posterior interosseous arteries. The cumflex humeral and subscapular arteries permits survival of the limb


vascular supply and lymphatic drainage
779
64
rETPaHC
after occlusion of either the third part of the subclavian artery, or of the Subclavian vein
axillary artery deep to the clavicle and pectoralis minor. The profunda
brachii is an important channel for the posterior muscles of the arm. It
accompanies the radial nerve and contributes to the collateral circula
tion about the elbow with the ulnar collateral and recurrent vessels and
the radial collateral and recurrent vessels. The anterior interosseous
artery is effectively an end artery. A series of anastomoses between the
radial and ulnar arteries, such as the transversely orientated palmar and
dorsal arches and the superficial and deep palmar arches, maintain a
rich blood supply to the wrist and hand. There are extensive intercon
nections between these arches and between the dorsal and palmar Vena comitans of
phalangeal arteries. Axillary vein profunda brachii artery
Pulses
Basilic vein piercing deep Cephalic vein
The pulsation of the subclavian artery is palpable at the lateral margin fascia to join venae comitantes of
of sternocleidomastoid and is easily blocked by digital pressure against brachial artery to form axillary vein
the first rib. This simple manœuvre has saved lives and limbs, and
should be widely known and rehearsed because it is the best method
for emergency control of bleeding from the deeply placed axillary artery.
The method was used successfully for high amputation or disarticula
tion of the shoulder in the Napoleonic wars. Vena comitans of
The brachial artery is palpable in the arm in the groove, or valley, brachial artery
between biceps brachii anteriorly and the medial head of triceps brachii
posteriorly; it can be traced down to the anterior aspect of the elbow,
Median cubital vein
where it moves towards the midline. The radial and ulnar pulses are
palpable at the wrist, where the vessels emerge from under the cover of
overlying muscles.
Vena comitans of
radial artery
VEINS
Median vein of forearm
The upper limb is drained by superficial and deep groups of vessels. Vena comitans of ulnar artery


The superficial group starts as an irregular dorsal arch on the back
Basilic vein
of the hand. The cephalic vein begins at the radial extremity of the arch,
and ascends along the lateral aspect of the arm within the superficial
fascia to enter the deltopectoral groove. It pierces the deep fascia above
the superior margin of pectoralis minor and enters the axillary vein
near the tip of the coracoid (Fig. 46.4). The basilic vein drains the ulnar
end of the arch, passes along the medial aspect of the forearm, pierces
the deep fascia at the elbow, and joins the venae comitantes of the
brachial artery to form the axillary vein. The prominent median cubital Cephalic vein
vein links the cephalic and basilic veins on the flexor aspect of the
elbow. It receives a number of tributaries from the flexor aspect of the Dorsal venous arch
forearm and gives off the deep median vein, which pierces the fascial
roof of the antecubital fossa to join the venae comitantes of the bra
chial artery. Superficial veins
The deep group of veins drains the tissues beneath the deep fascia
Deep veins
of the upper limb and is connected to the superficial system by perforat
ing veins. The deep veins accompany the arteries, usually as venae
Dorsal digital veins
comitantes, ultimately becoming the axillary, and subsequently the
subclavian, vein.
The subclavian vein is the central continuation of the axillary vein.
It starts at the inferior margin of the first rib, which it crosses. Initially
Fig . 46 .4 The veins of the upper limb .
deep to the clavicular head of pectoralis major and then to subclavius,
which is a buffer between it and the overlying medial portion of the
clavicle, the vein then runs deep to the insertion of sternocleidomas
toid. Sometimes, only the superior margins of the vein rise above the
Proximally based flaps of skin caused by ‘degloving’ injury are more
medial end of the clavicle; sometimes, the entire vein does so. The
likely to survive; even a distally based flap of palmar skin may do so.


phrenic nerve and the inferior part of scalenus anterior lie posteriorly.
The skin of the lower leg is notoriously sensitive to the effects of fracture
The subclavian vein joins the internal jugular vein to form the brachio
because of rupture of the vessels perforating the deep fascia; this
cephalic vein at the medial border of scalenus anterior, behind the
problem is less severe in the upper limb. Three interconnected pathways
sternoclavicular joint (see Fig. 29.14). A pair of valves usually lies within
may be recognized in the upper limb, namely: muscle perforators, deep
2 cm of this junction. The subclavian vein receives, as tributaries, the
fasciocutaneous vessels and the direct cutaneous supply.
external jugular, dorsal scapular and, sometimes, the anterior jugular
veins. The trifurcation of subclavian, external and internal jugular veins
is demonstrable by a forced expiration (Valsalva) manœuvre, when the Muscle perforators
distended veins rise up above the sternoclavicular joint, filling the fossa
above the jugular notch of the sternum (Video 46.1). Main lymphatic Available with the Gray’s Anatomy e-book
vessels join the subclavian veins at, or very close to, this junction with
the internal jugular vein. The left subclavian vein receives the thoracic
duct; the right receives the right lymphatic duct (see Fig. 29.16). There Fasciocutaneous system
is a risk of air embolism after wounding of the subclavian, external or
internal jugular veins. Available with the Gray’s Anatomy e-book
Cutaneous blood supply
Direct cutaneous supply
The blood supply of the skin of the upper limb is generally abundant
Available with the Gray’s Anatomy e-book (Fig. 46.5) and rather more robust than that in the lower limb.


Pectoral girdle and upper limb: overview and surface anatomy
779.e1
64
rETPaHC
Vessels pass from deep axial vessels through muscle, perforate the deep
fascia and supply the overlying skin. The latissimus dorsi myocutaneous
flap based on the thoracodorsal vessels was an important development
in plastic and reconstructive surgery, not only for the replacement of
lost skin or reconstruction of the breast, but also in the evolution of
the freefunctioning muscle transfer.
The fasciocutaneous system rests on branches that arise from deep
vessels and pass along intermuscular septa to perforate the deep fascia
and ramify over its surface; extensive areas of skin are supplied in this
way. The development of fasciocutaneous flaps, either as pedicle flaps
or free grafts, has been a revolutionary advance in the treatment of
severe wounds; not only is it possible to replace large areas of lost skin,
but also the improvement of the tissue bed that overlies the main nerves
enhances regeneration and relieves neuropathic pain.
The direct cutaneous supply is exemplified in the palmar skin, where
branches from the underlying digital vessels pass directly into the over
lying skin.


PECTOral GIrdlE aNd UPPEr lImb: OvErvIEw aNd SUrfaCE aNaTOmy
780
6
NOITCES
A Posterior B Anterior
8 1
1
9 2 5
5
6 6
3
7
10
4
12 12
11
13 13
15
14
17
1 Transverse cervical artery 10 Circumflex scapular artery
16 2 Direct cutaneous branch from 11 Musculocutaneous perforators
thoraco-acromial axis through latissimus dorsi arising from 16
18
intercostal and thoracodorsal arteries
3 Anterior perforators from
19 18 internal thoracic artery/ 12 Middle and radial collateral arteries
musculocutaneous perforators
13 Superficial ulnar collateral
from pectoral branch of
and brachial arteries
thoraco-acromial axis
4 Superficial thoracic artery 14 Olecranon anastomosis 20
20
5 Musculocutaneous perforators 15 Radial recurrent
from deltoid branch of 16 Radial artery
thoraco-acromial axis
17 Anterior ulnar recurrent
6 Posterior circumflex
humeral artery 18 Ulnar artery
7 Anterior circumflex 19 Posterior interosseous artery
humeral artery
20 Anterior interosseous artery
8 Posterior intercostal artery
9 Dorsal scapular artery
Fig . 46 .5 The anatomical territories served by the cutaneous blood supply to the upper limb . (With permission from Cormack GC, Lamberty BGH 1994
The Arterial Anatomy of Skin Flaps, 2nd ed . Edinburgh: Churchill Livingstone .)
LYMPHATIC DRAINAGE deep fascia with the basilic vein and end in the lateral axillary nodes or
deep lymphatic vessels.
Superficial tissues Collecting vessels from the deltoid region pass round the anterior
and posterior axillary folds to end in the axillary nodes. The scapular
Superficial lymphatic vessels begin in cutaneous plexuses. In the hand,
skin drains either to subscapular axillary nodes or by channels that
the palmar plexus is denser than the dorsal plexus. Digital plexuses


follow the transverse cervical vessels to the inferior deep cervical nodes.
drain along the digital borders to their webs, where they join the distal
palmar vessels, which pass back to the dorsal aspect of the hand. The
Deeper tissues
proximal palm drains towards the carpus, medially by vessels that run
Deep lymph vessels follow the main neurovascular bundles (radial,
along its ulnar border, and laterally to join vessels draining the thumb.
ulnar, interosseous and brachial) to the lateral axillary nodes. They are
Several vessels from the central palmar plexus form a trunk that winds
less numerous than the superficial vessels and communicate with them
round the second metacarpal bone to join the dorsal vessels that drain
at intervals. A few lymph nodes occur along the vessels. Scapular
the index finger and thumb.
muscles drain mainly to the subscapular axillary nodes, and pectoral
In the forearm and arm, superficial vessels run with the superficial
muscles drain mainly to the pectoral, central and apical nodes.
veins. Collecting vessels from the hand pass into the forearm on all
Efferent vessels from the deep cervical nodes form the jugular trunk.
carpal aspects. Dorsal vessels, after running proximally in parallel, curve
The right jugular trunk drains the right upper limb, the right half of the
successively round the borders of the limb to join the ventral vessels.
thorax and the right head and neck, and enters the right thoracic duct
Anterior carpal vessels run through the forearm parallel with the median
or directly enters the right subclavian vein close to its junction with the
vein of the forearm to the cubital region, then follow the medial border
internal jugular. The left jugular trunk usually enters the thoracic duct,
of biceps brachii before piercing the deep fascia at the anterior axillary
but it may directly enter either the subclavian or internal jugular vein
fold to end in the lateral axillary lymph nodes.
(see Figs 29.16, 48.45).
Lymph vessels that lie laterally in the forearm receive vessels that
curve round the lateral border from the dorsal aspect of the limb. They
follow the cephalic vein to the level of the tendon of deltoid, where
INNERVATION


most incline medially to reach the lateral axillary nodes; a few continue
with the vein and drain into the infraclavicular nodes. Vessels lying
medially in the forearm are joined by vessels that curve round the The accessory nerve, dorsal scapular nerve, long thoracic nerve (nerve
medial border of the limb and follow the basilic vein. Proximal to to serratus anterior), suprascapular nerve and nerve to subclavius all
the elbow, some end in supratrochlear lymph nodes whose efferents, innervate muscles that act on the scapulothoracic ‘joint’ and therefore
together with the medial vessels that have bypassed them, pierce the will be summarized here.


Innervation
781
64
rETPaHC
accessory nerve
Roots Trunks Divisions Cords Terminal
The integrity of the accessory nerve is fundamental to thoracoscapular
(ventral rami) nerves
function and essential for scapulohumeral rhythm (Camp and Birch
2011). The intraspinal and intracranial course of the accessory nerve and Dorsal scapular nerve Suprascapular nerve Lateral pectoral nerve Musculocutaneous
of the segment of the nerve that lies in the anterior triangle are described C5
on page 467.
Contribution
The accessory nerve passes either deep to or through sternocleido to phrenic Upper Anterior Lateral
mastoid, to enter the posterior triangle in a consistent and important nerve
ur lae srl ua
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i s
o
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ee
a tks ruc ee
y
nn ktd
o
,
i 5n
e
–xg
1p
n 0oe
s
mr uv re mes oo cff
e
pt th
h
he
e
a
lc
a
ae
c
dr cv
e
ti
s
oc sa
o
tl
h
rp
y
el e
n
px
e
ou
r
ivs n.
e
t,T wwhe
hh
eig
c
rr
h
ee a tet
hm
a eu
e
gr ri rgc eeu as
t,
C6
Nerve to subclavius
Anterior
P osterior
Axillary Median
auricular nerve winds around sternocleidomastoid, and moves from a C7 Middle Posterior Radial
plane posterior to the muscle to one that is anterior. The general rela
t ri eo lan ts
i
oo nf bth ee
tw
p eo es nt e tr hio
e
r twtr oia n ng el re
v
ev sa r iy
s
rw ei lt ih
ab
i ln
y
d ci ov nid su isa tl
e
np th
.
y Ts hiq eu ne,
e
rb vu et nt oh wis
C8
Posterior
su Tb hs
ocS rau app
cu
oe
l


dari oro rr
n se ar lv ne
erve
Inferior subscapular nerve
runs across the fatty areolar tissue at the apex of the posterior triangle,
in close relation to the superior superficial cervical lymph nodes deep Lower Anterior Medial Ulnar
to platysma. It is separated from the underlying levator scapulae by this
areolar tissue, and then, more deeply, by the prevertebral fascia. One T1
slender branch passes to the upper fibres of trapezius either deep to Medial pectoral
sternocleidomastoid or just beyond it. The nerve pierces the fascia cov Long thoracic Medial cutaneous nerve of arm
ering the deep surface of trapezius close to the anterior border of the nerve Medial cutaneous nerve of forearm
muscle and then runs caudally about 2 cm from that border. The nerve
passes down in a characteristic sinuous fashion, accompanied by Posterior divisions of the trunks and their derivatives
slender vessels to the deep, inner face of trapezius. A branch from the
Fibres from C7 that contribute to the ulnar nerve
cervical plexus (C3, 4) joins the nerve just above the clavicle. Intraopera
tive stimulation of this branch rarely evokes a muscular response; it Fig . 46 .6 A schematic plan of the brachial plexus . (Adapted with
probably conveys afferent fibres from the middle and lower parts of permission from Drake RL, Vogl AW, Mitchell A (eds), Gray’s Anatomy for
trapezius. The nerve now turns medially, continuing in parallel to the Students, 2nd ed, Elsevier, Churchill Livingstone . Copyright 2010 .)
spine of the scapula about 4 cm above it. At the medial end of the spine,
the nerve turns caudally again, passing down parallel to the medial
border of the scapula. It divides into terminal muscular branches about at operation. A muscular contribution from T2 is rare. The rami enter
7 cm distal to the scapular spine. Although sternocleidomastoid, and the posterior triangle of the neck between scalenus anterior and medius.
the middle and the lower portions of trapezius, may be partially sup Rami from C7 and C8 are the largest (C8 contains about 30,000 myeli


plied by branches from the cervical plexus, the upper part of trapezius nated axons) and those from C5 and T1 are the smallest (between
is innervated solely by the accessory nerve. 15,000 and 20,000 myelinated axons). An adult brachial plexus con
tains between 120,000 and 150,000 myelinated axons, of which 25%
dorsal scapular nerve
innervate the shoulder girdle and glenohumeral joint. The proportion
The dorsal scapular nerve arises above the clavicle from the proximal of motor fibres is greatest in C5 and C8; the sensory contribution is
segment of the ventral primary ramus of C5. It passes posteriorly, pier greatest in C7. A complex interchange of branches, before the main
cing scalenus medius, to run down in the plane between levator scapu nerves of the upper limb are formed, produces the trunks, divisions and
lae and serratus posterior superior and the posterior scalene muscles. It cords of the brachial plexus.
continues along the anterior border of the rhomboid muscles about
1.5 cm medial to the vertebral border of the scapula and is closely Blood supply The blood supply of the brachial plexus is derived from
related to the dorsal scapular artery. The dorsal scapular nerve inner vessels arising from the subclavian and vertebral arteries. Important
vates the rhomboid muscles and, together with branches from C3 and branches pass from the vertebral artery to the rami of C5 and C6 and
C4, it supplies levator scapulae. the more proximal cervical nerves. Branches from the costocervical
trunk provide a rich supply to T1 and C8. Extensive contributions come
long thoracic nerve (nerve to serratus anterior) from the suprascapular and superficial cervical arteries that arise from
The long thoracic nerve is formed by branches that arise above the the thyrocervical trunk. In at least onethird of cases, the superficial
clavicle from the proximal segments of the ventral primary rami of C5, cervical and dorsal scapular arteries arise from the thyrocervical trunk


C6 and C7. It innervates serratus anterior, a muscle that is essential for as the transverse cervical artery. In clinical terms, the arteries arising
the function of the thoracoscapular joint. The muscular branches from from the thyrocervical trunk have become the lifeline to the upper limb
the rami join deep to scalenus medius, and the trunk passes down and must be preserved during operations in cases when the ruptured
posterolateral to the muscle, on the floor of the posterior triangle deep subclavian artery has not been repaired. The dorsal scapular artery may
to the suprascapular nerve. The branches from C5 and C6 are the largest. arise from the third part of the subclavian artery to pass between the
The nerve follows a sinuous course deep to the investing fascia covering upper and middle trunks of the brachial plexus.
the anterior faces of the digitations of serratus anterior. It is accompa
Trunks of the brachial plexus
nied here by a branch of the thoracodorsal artery, and trends postero
laterally towards the midaxillary line. The upper trunk is formed by C5 and C6, where these nerves emerge
from deep to scalenus anterior. The middle trunk is the continuation
Suprascapular nerve of C7. The lower trunk is formed by C8 and T1, where these nerves cross
The suprascapular nerve (C5, 6) usually arises as the first branch of the anterior to the first rib. The ramus of T1 takes an upward course across
upper trunk but it frequently springs directly from the ventral primary the deep face of the neck of the first rib behind the pleura and the
ramus of C5. It innervates supra and infraspinatus. vertebral and subclavian arteries towards the lower trunk. The forma
tion of the trunks is fairly consistent; they lie in front of one another
Nerve to subclavius rather than side by side, with the subclavian artery passing anteromedi
The slender nerve to subclavius (C5, 6) springs from the upper trunk ally. The phrenic nerve crosses C5 to pass anteromedially on the surface


and passes anteriorly. It descends anterior to the plexus and the subcla of scalenus anterior. The upper trunk, its divisions and the suprascapu
vian artery and passes above the subclavian vein to supply subclavius. lar nerve can all be palpated in the supraclavicular fossa in a subject of
normal physique. The examining finger identifies first the subclavian
pulse and then the nerves, whilst rolling the fingertip laterally (see
Brachial plexus
Video 46.1).
Divisions of the brachial plexus
The muscles, joints and skin of the upper limb are innervated by the
ventral primary rami of C5, C6, C7 and C8, and nearly all of the ventral The trunks divide into anterior and posterior divisions. The upper trunk
primary ramus from T1, collectively forming the brachial plexus (Figs divides 2–3 cm above the clavicle, and the divisions of the middle and
46.6–46.7). A branch from C4 to C5, which contributes to the innerva lower trunk are formed deep to the clavicle. The posterior divisions of
tion of the glenohumeral and elbow flexor muscles, is seen occasionally the upper and middle trunks are consistently larger than their anterior


PECTOral GIrdlE aNd UPPEr lImb: OvErvIEw aNd SUrfaCE aNaTOmy
782
6
NOITCES
C1
C2
C3
Dorsal scapular nerve
C4
Phrenic nerve
C5
Upper trunk
C6
Middle trunk
Long thoracic nerve
Medial cord Lower trunk C7
Suprascapular nerve C8
Lateral cord
Posterior cord
T1
Lateral pectoral nerve
Medial pectoral nerve
Thoracodorsal nerve
Axillary nerve
Medial cutaneous nerve of forearm
Axillary artery
Medial cutaneous nerve of arm
Median nerve
Ulnar nerve
Musculocutaneous nerve
Radial nerve
Fig . 46 .7 The brachial plexus . Note the sequence: ventral (anterior) primary rami; trunks; divisions; cords; nerves . The trunks are upper, middle and
lower, and the cords are lateral, medial and posterior, according to their position in relation to the axillary artery, which is variable . (Courtesy of Rolfe
Birch, all rights reserved, published in Birch R, Surgical Disorders of the Peripheral Nerve, 2nd ed, 2011 . Springer-Verlag, London .)
divisions. The posterior division of the lower trunk is consistently The formation and relations of the three cords are variable and,
smaller than the anterior division and is absent in about 10% of indeed, their designations somewhat misleading. Immediately inferior
cases. to the clavicle, the posterior cord is lateral, the medial cord is posterior,
and the lateral cord is anterior, in relation to the axillary artery; the
Cords of the brachial plexus
cords assume their appropriate relations about the axillary artery deep
The cords are formed by the confluence of divisions: the lateral cord to pectoralis minor. There is considerable variation in this arrangement;
from the anterior divisions of the upper and middle trunks; the pos most commonly, the axillary artery lies anterior to the three cords and
terior cord by all three posterior divisions; and the medial cord by the the median nerve.
anterior division of the lower trunk and, sometimes, by a branch from The branches of the posterior cord, the largest of the three trunks,


the anterior division of the middle trunks. The divisions of the trunks are consistent. In sequence, they are the upper subscapular, thoracodor
and the formation of the cords represent an important anatomical and sal, lower subscapular, axillary and radial nerves. The branches of the
functional differentiation. The posterior divisions and posterior cord medial cord are usually predictable; the medial pectoral nerve and
innervate postaxial (extensor) musculature; the anterior divisions and medial cutaneous nerve of the forearm are succeeded by the division
the lateral and medial cords innervate preaxial (flexor) musculature. into the medial root of the median nerve and the ulnar nerve. The ulnar


Innervation
783
64
rETPaHC
Axillary nerve
Axillary nerve
Radial nerve
Deltoid
Upper lateral
Teres minor cutaneous Triceps, long head
nerve of arm
Triceps, lateral head
Triceps, medial head
Radial nerve
Brachioradialis
Extensor carpi radialis longus
Extensor carpi radialis brevis
Posterior interosseous
Fig . 46 .8 Motor and sensory branches of the axillary nerve . (With nerve (deep branch) Supinator
permission from O’Brien M, Aids to the Examination of the Peripheral
Extensor carpi ulnaris
Nervous System, 5th ed, 2010, Edinburgh: Saunders, Elsevier .)
Extensor digitorum
Extensor digiti minimi
nerve may arise as two or three branches. The greatest variation in for Abductor pollicis longus
mation of trunk nerves is found within the lateral cord. Occasionally,
Extensor pollicis longus
the musculocutaneous nerve arises more distally than usual, springing
either directly from the lateral cord as two or three branches or even Extensor pollicis brevis
from the median nerve itself. Sometimes, the highest of these branches
Extensor indicis
enters coracobrachialis no more than 2 or 3 cm below the coracoid
process. The lateral root of the median nerve may arise as two or three
branches, and in some cases, it appears as a branch of the musculo
cutaneous nerve.
Superficial radial nerve
axillary (circumflex) nerve
The axillary nerve (C5, 6) (Fig. 46.8) runs freely in loose fatty tissue in
the axilla before turning around subscapularis to pass almost horizon
tally through the quadrilateral tunnel, where it is accompanied by the
posterior circumflex humeral vessels (see Fig. 48.33). It innervates teres
minor and deltoid, and the skin overlying deltoid on the lateral aspect
of the shoulder.
radial nerve
The radial nerve (C5, 6, 7, 8, T1) is the terminal branch of the posterior
cord (Fig. 46.9). It is the largest nerve in the upper limb and the most


commonly damaged. Between its origin at the level of the base of the
coracoid and its entrance into the spiral groove, where it is accompanied
by the profunda brachii artery, the radial nerve is supplied by fewer
arteries than elsewhere along its course. The first 8–10 cm of the nerve
may not have a nutrient artery and will, therefore, be relatively avascular
if the nerve is transected at its origin. The nerve lies closest to the bone Fig . 46 .9 Motor and sensory branches of the radial nerve . Variation exists
where it pierces the lateral intermuscular septum to pass through a short in the cutaneous innervation of the dorsal aspects of the digits . Here, the
tunnel bounded by bone and unyielding fascia. The nerve is tethered radial nerve is shown to supply all five digits; the skin of the dorsum of
here, a common level of rupture, entrapment or compression. the ring and little fingers is frequently innervated by the dorsal branch of
The nerve to the medial head of triceps arises in the axilla and the ulnar nerve . (With permission from O’Brien M, Aids to the Examination
accompanies the main nerve as it passes through the intermuscular of the Peripheral Nervous System, 5th ed, 2010, Edinburgh: Saunders,
septum. The nerve(s) to the lateral head of triceps arise(s) within the Elsevier .)
spiral groove; that to the lateral head just before the radial nerve
reenters the anterior compartment. Two cutaneous nerves, the lower
lateral cutaneous nerve of the arm and the posterior cutaneous nerve seous and superficial radial nerves. Another branch to extensor carpi
of the forearm, pass away from the main nerve in the final part of the radialis brevis is usually given off here. The superficial radial nerve
spiral groove and course along the anterior face of the lateral head of innervates the skin over the dorsum of the radial half of the ring, middle
triceps to perforate the deep fascia about four fingers’breadths above and index fingers, and that of the thumb as far as the distal interphalan
the lateral epicondyle. They innervate the skin of the lower lateral arm geal joint. It often provides important sensation on the skin of the


and the posterior aspect of the forearm. thumb web space and the skin on the adjacent sides of the thumb and
The nerve to brachioradialis is formed about three fingers’breadths index.
proximal to the lateral epicondyle; the nerve to extensor carpi radialis
longus about one finger’sbreadth more distal; and that to extensor median nerve
carpi radialis brevis about one finger’sbreadth above the epicondyle. The median nerve is formed by the union of the lateral root (C6, 7)
These branches spring from the main nerve as it runs in the valley from the lateral cord, and the medial root (C8, T1) from the medial
between brachialis anteriorly and brachioradialis posteriorly, which is cord, which meet anterior to the third part of the axillary artery (Fig.
a site where the nerve may be palpated. At the level of the tip of the 46.10). Fibres in the lateral root innervate the palmar skin of the thumb,
lateral epicondyle, the radial nerve divides into the posterior interos index and most of the middle fingers, and pronator teres, flexor carpi


PECTOral GIrdlE aNd UPPEr lImb: OvErvIEw aNd SUrfaCE aNaTOmy
784
6
NOITCES
Recurrent branch of
median nerve
Median nerve Palmar cutaneous Flexor retinaculum
branch of median nerve
Flexor carpi radialis
Median nerve
Pronator teres Flexor digitorum
superficialis
Flexor carpi radialis
Palmaris longus
Anterior interosseous nerve
Fig . 46 .11 The normal course of the median nerve and the palmar
Flexor digitorum
cutaneous nerve at the wrist . (Courtesy of Rolfe Birch, all rights reserved,
Flexor digitorum profundus to index superficialis
published in Birch R, Surgical Disorders of the Peripheral Nerve, 2nd ed,
and middle fingers
2011 . Springer-Verlag, London .)
Flexor pollicis longus
quadratus. There is no cutaneous distribution. The main nerve contin
ues in the plane between the superficial and deep digital flexors, sup
plying two or three branches to the former. The palmar cutaneous nerve
arises about 3 cm proximal to the proximal wrist crease, and passes
lateral to the main nerve and superficial to the flexor retinaculum to
Pronator quadratus
innervate the skin of the proximal palm. The median nerve passes deep
Palmar branch to the flexor retinaculum, into the carpal tunnel, to enter the palm. The
nerve to the thenar muscles arises within, or just distal to, the tunnel,
Sensory Motor usually on the lateral side of the main nerve. The palmar digital nerves
Flexor retinaculum
are formed within the palm of the hand.
Abductor pollicis brevis
The nerve is palpable along its course in the arm, where it is covered
Flexor pollicis brevis
by deep fascia and skin, after emerging from deep to coracobrachialis.
Opponens pollicis It is palpable on the flexor aspect of the elbow, deep to the bicipital
First lumbrical aponeurosis, and is accompanied by the brachial artery in this segment
of the limb. The median nerve is palpable at the wrist where it emerges
from behind the superficial flexor tendons, just lateral to palmaris


longus.
Second lumbrical
Ulnar nerve
The ulnar nerve (C7, C8, T1) is the continuation of the medial cord
(Fig. 46.12). It inclines posteromedially to perforate the medial inter
muscular septum about 10 cm proximal to the medial epicondyle and
Fig . 46 .10 Motor and sensory branches of the median nerve . Flexor
passes through a fibrous canal, the arcade of Struthers, which is between
pollicis brevis may be supplied by both median and ulnar nerves . (With
5 and 6 cm long. The walls of the canal include the medial intermus
permission from O’Brien M, Aids to the Examination of the Peripheral
cular septum and the fascial sheath investing the medial head of triceps
Nervous System, 5th ed, 2010, Edinburgh: Saunders, Elsevier .)
brachii. The nerve next passes behind the medial epicondyle, then
between the capsule of the humeroulnar joint and the overlying arcuate
ligament, which joins the two origins of flexor carpi ulnaris, i.e. the
nerve passes through the cubital tunnel. It is accompanied by the supe
radialis and some of flexor digitorum superficialis (Fig. 46.11). The rior collateral ulnar vessels in the lower third of the arm as far as the
lateral root conveys most of the sympathetic fibres to the median dis entrance to the cubital tunnel, and then by the posteroinferior ulnar
tribution in the hand. The medial root carries fibres to the skin of the collateral vessels. The anastomosis between these vessels permits the
medial side of the middle and the lateral side of the ring finger, and use of most of the ulnar nerve as a free vascularized graft, in cases where
also fibres to palmaris longus, flexor digitorum superficialis and the the parent nerves, C7, C8 and T1, are irreparable. In the forearm, the
lateral part of flexor digitorum profundus, flexor pollicis longus, prona nerve runs with the ulnar vessels in a welldefined sheath deep to the


tor quadratus and the median innervated muscles within the hand. The anterior margin of flexor carpi ulnaris. It divides into superficial
first branch of the median nerve, to pronator teres, arises 2–3 cm above (sensory) and deep (motor) components at the wrist, both passing
the medial epicondyle. A second branch, or leash of branches, arises at through Guyon’s canal.
the level of the tip of the medial epicondyle and innervates palmaris The superficial division innervates the skin of the medial two digits
longus, flexor carpi radialis and flexor digitorum superficialis. Just proxi and palmaris brevis. The deep branch passes, with the deep branch of
mal to the tendinous arcade of flexor digitorum superficialis, the the ulnar artery, between abductor and flexor digiti minimi, pierces
median nerve gives off the anterior interosseous nerve. Accompanied opponens digiti minimi and then runs across the deep palmar space
by the anterior interosseous vessels, this large branch dives deeply to with the deep palmar arch. It innervates all the muscles of the hand,
pass down along the interosseous membrane and supplies flexor pol except for the first and second (index and middle) lumbricals, abductor
licis longus, the radial half of flexor digitorum profundus and pronator pollicis brevis, opponens pollicis and part of flexor pollicis brevis.


Innervation
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Coracobrachialis
Musculocutaneous
Sensory nerve
Dorsal cutaneous
Ulnar nerve
branch
Biceps brachii
Medial cutaneous
nerve of arm
Brachialis
Palmar cutaneous
branch
Deep motor branch
Superficial terminal
branches
Flexor carpi ulnaris
Flexor digitorum
profundus to ring
and little finger
Lateral cutaneous nerve
of forearm
Medial cutaneous
nerve of forearm
Motor
Adductor pollicis
Abductor
Flexor pollicis brevis
Digiti minimi Opponens
Flexor
First dorsal interosseous
First palmar interosseous
Fourth lumbrical Third lumbrical
Fig . 46 .12 Motor and sensory branches of the ulnar nerve and the medial
cutaneous nerves of the arm and the forearm . Flexor pollicis brevis may Fig . 46 .13 Motor and sensory branches of the musculocutaneous nerve .
be supplied by both median and ulnar nerves . (With permission from (With permission from O’Brien M, Aids to the Examination of the
O’Brien M, Aids to the Examination of the Peripheral Nervous System, Peripheral Nervous System, 5th ed, 2010, Edinburgh: Saunders, Elsevier) .
5th ed, 2010, Edinburgh: Saunders, Elsevier .)
The dorsal cutaneous branch can be palpated in those of slender
physique where it crosses the subcutaneous ulna.
A branch to the medial head of triceps is often given off in the distal
third of the arm. There are usually two neurovascular pedicles to flexor musculocutaneous nerve
carpi ulnaris, the first at the exit from the cubital tunnel, the second The musculocutaneous nerve (C5, 6, 7) is one of the two terminal
about onequarter of the way down the forearm. Several branches pass branches of the lateral cord, the other being the lateral root of the
to flexor digitorum profundus. The dorsal cutaneous nerve arises about median nerve (Fig. 46.13). This division usually occurs at the level of


6 cm proximal to the ulnar styloid, winds around the ulna, at first deep the third part of axillary artery, where the lateral cord is lateral to the
to flexor carpi ulnaris, and then subcutaneously. It innervates the skin vessel, but it may occur more proximally, where the cord is anterior to
of the dorsum of the hand and little finger, and the medial side of the the second part of the artery. The nerve may also arise as two or three
ring finger. branches from the cord, or even from the median nerve. It supplies
The ulnar nerve is palpable in the lower arm and behind the medial coracobrachialis, both heads of biceps brachii and most of brachialis,
epicondyle, where it is subcutaneous. There is an important relation and continues as the lateral cutaneous nerve of forearm, deep to biceps,
here: a posterior branch of the medial cutaneous nerve of the forearm before emerging lateral to it about 11 cm above the lateral epicondyle,
sweeps across the cubital tunnel and gets in the way of medial surgical and then running down the lateral aspect of the forearm. The nerve
exposures. Inadvertent injury may cause severe pain. The ulnar nerve is sometimes innervates the skin over the first metacarpal and the lateral
palpable at the wrist where it emerges from under flexor carpi ulnaris. part of the thenar eminence.


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Segmental innervation of the upper limb C5 regularly controls extension, abduction and lateral rotation of
the shoulder. C6 usually innervates biceps brachii, brachialis, lateral
head of triceps, brachioradialis, extensor carpi radialis longus, and
There is a segmental pattern to the innervation of the upper limb. The
sometimes contributes to the innervation of pronator teres, supinator
most proximal muscles are supplied by branches of the uppermost
and flexor carpi radialis. C7 gives widespread innervation throughout
rami, and the most distal muscles are supplied by branches derived
the limb; in those unusual instances where it alone is damaged, the
from C8 and T1. The segmental pattern of innervation is shown more
patient will note a rather diffuse loss of function throughout the upper
clearly in the cutaneous supply. The cervical supply has been, as it were,
limb, often without complete anaesthesia and sometimes without
extruded from the supply to the trunk. Thus, in the transition of cutane
paralysis of any single significant muscle group. C7 consistently sup
ous innervation from the skin of the neck to that of the trunk, there is
plies latissimus dorsi. C8 innervates the extensors of the digits and of
a change from the fourth cervical to the second thoracic segment anter
the thumb in at least onethird of cases. T1 innervates these muscles
iorly, and a change from the fifth cervical to the first thoracic segment
and also the medial head of triceps in at least 10%. Muscles, movements
posteriorly (Figs 46.14–46.15; see Fig. 16.10 for other variations). (For
and segmental innervation in the upper limb are set out in Tables
further reading, see Ladak et al (2014).) The truly autonomous area of
46.1–46.3. Table 46.4 helps to distinguish between upper and lower
cutaneous supply of each main component nerve is small and variable
motor neurone lesions.
in extent and location.
Autonomic nerves


The preganglionic sympathetic inflow to the upper limb is derived from
neurones in the intermediolateral horn of spinal cord segments T2–6/7.
C3
Myelinated preganglionic axons pass from the spinal nerves to the
C4 thoracic sympathetic chain via white rami communicates. They pass up
the chain to the middle cervical and inferior cervical (stellate or cervico
T2 thoracic) ganglia, where they relay.
C5
T3 The unmyelinated postganglionic fibres are distributed by grey rami
T4 communicantes to the nerves of origin of the brachial plexus. C5 and
C6 receive grey rami from the middle cervical ganglion; C7 and C8
T5
receive grey rami from the inferior cervical ganglion; T1 not only
T2
T6 receives a grey ramus from the inferior cervical ganglion but also con
T7 tributes a white ramus to it (see Figs 16.13, Fig. 46.16). Interruption of
this white ramus is one cause of Horner’s (Bernard–Horner) syndrome:
T8
drooping eyelid, narrow palpebral fissure, a contracted pupil, and vaso
C6 T1 T9 motor with sudomotor paralysis in the ipsilateral face and neck. The
T10 sympathetic outflow to the upper limb passes with the peripheral nerves
and is particularly rich in the palmar skin of the hand and in the skin
T11
of the axilla.
T12
C6
L1
CLINICAL DIAGNOSIS OF FOCAL NERVE LESIONS
IN THE UPPER LIMB
C7
C8 Available with the Gray’s Anatomy e-book
Fig . 46 .14 Approximate distribution of the dermatomes on the posterior
aspect of the upper limb . (Courtesy of Rolfe Birch, all rights reserved,
published in Birch R, Surgical Disorders of the Peripheral Nerve, 2nd ed,
ACUTE ISCHAEMIA AND COMPARTMENT
2011 . Springer-Verlag, London .)
SYNDROMES IN THE UPPER LIMB
Available with the Gray’s Anatomy e-book
C3
C4
SURFACE ANATOMY
T2
C5
SKELETAL LANDMARKS
T3


T4 The clavicle is both visible and palpable from its prominent and rela
T2 tively rounded medial (sternal) end, which forms the lateral boundary
T5
of the suprasternal notch, to its flattened lateral end, where it joins the
T6 acromion (Fig. 46.29A). The acromioclavicular joint line is palpable as
an anteroposteriorly aligned ridge or groove. The anterior, superior and
T7 C6 lateral surfaces of the acromion are subcutaneous and palpable (Fig.
T1 46.29C). Posteriorly, the palpable acromial angle marks the junction of
T8
the acromion with the crest of the scapular spine. From this point, the
T9 spine of the scapula, which is subcutaneous and easily visible in thin
subjects, is palpable to the medial (vertebral) border of the scapula,
T10
C6 where it lies opposite the spine of the third thoracic vertebra.
T11 The medial border of the scapula, superior to the level of the scapu
lar spine, is covered by trapezius and, therefore, difficult to palpate.
T12
Below the spine, the medial border is palpable down to the inferior
L1 angle. Although covered by teres major and latissimus dorsi, the inferior
C7 angle is palpable when approached inferiorly, and can be seen and/or
C8 palpated as it moves around the thoracic wall during shoulder move
Fig . 46 .15 Approximate distribution of the dermatomes on the anterior ments. The inferior angle is opposite the spine of the seventh thoracic
aspect of the upper limb . (Courtesy of Rolfe Birch, all rights reserved, vertebra and overlies the seventh rib; it is a convenient landmark from
published in Birch R, Surgical Disorders of the Peripheral Nerve, 2nd ed, which the ribs can be counted along the lateral chest wall, e.g. when a
2011 . Springer-Verlag, London .) thoracotomy is being performed.


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Table 46.1 Movements, muscles and segmental innervation in the upper limb
Joint Movement Muscle Innervation C3 C4 C5 C6 C7 C8 T1
SCAPULA ELEVATION Upper trapezius Accessory n.
Levator scapulae Dorsal scapular n.
DEPRESSION Lower trapezius Accessory n.
RETRACTION Middle trapezius Accessory n.
Rhomboids Dorsal scapular n.
SHOULDER PROTRACTION Serratus anterior Long thoracic n.
FLEXION Anterior deltoid Axillary n.
Pectoralis major (clavicular head) Medial and lateral pectoral nn.
Pectoralis major (sternocostal head) Medial and lateral pectoral nn.
Coracobrachialis Musculocutaneous n.
EXTENSION Posterior deltoid Posterior deltoid
Infraspinatus Suprascapular n.
Teres minor Axillary n.
Teres major Lower subscapular n.
Latissimus dorsi Thoracodorsal n.
VERTICAL ABDUCTION Middle deltoid Axillary n.
Supraspinatus Suprascapular n.
VERTICAL ADDUCTION Pectoralis major (sternocostal head) Medial and lateral pectoral nn.
Latissimus dorsi Thoracodorsal n.
Coracobrachialis Musculocutaneous n.
HORIZONTAL ABDUCTION Posterior deltoid Axillary n.
HORIZONTAL ADDUCTION Pectoralis major (clavicular head) Medial and lateral pectoral nn.
Pectoralis minor Medial and lateral pectoral nn.
Anterior deltoid Axillary n.
MEDIAL ROTATION Subscapularis: Upper and lower subscapular nn.
Teres major Brachial plexus
Latissimus dorsi Thoracodorsal n.
Anterior deltoid Axillary n.
LATERAL ROTATION Infraspinatus Suprascapular n.
Teres minor Axillary n.
Posterior deltoid Axillary n.
ELBOW FLEXION Biceps brachii Musculocutaneous n.
Brachialis Musculocutaneous and radial nn.
Brachioradialis Radial n.


EXTENSION Triceps brachii Radial n.
SUPINATION* Biceps brachii Musculocutaneous n.
Supinator Posterior interosseous n.
PRONATION* Pronator quadratus Anterior interosseous n.
Pronator teres Median n.
WRIST FLEXION Flexor carpi radialis Median n.
Palmaris longus Median n.
Flexor carpi ulnaris Ulnar n.
EXTENSION Extensor carpi radialis longus Radial n.
Extensor carpi radialis brevis Posterior interosseous n.
Extensor carpi ulnaris Posterior interosseous n.
ABDUCTION Extensor carpi radialis longus Radial n.
Extensor carpi radialis brevis Posterior interosseous n.
Flexor carpi radialis Median n.
ADDUCTION Extensor carpi ulnaris Posterior interosseous n.
Flexor carpi ulnaris Ulnar n.
FINGERS FLEXION (MP/PIP joints) Flexor digitorum superficialis Median n.
Dorsal interossei Ulnar n.
Palmar interossei Ulnar n.
FLEXION (DIP joints) Flexor digitorum profundus (lateral) Anterior interosseous n.
Flexor digitorum profundus (medial) Ulnar n.
FLEXION (MP joint) Flexor digiti minimi brevis Ulnar n.
EXTENSION (MP/PIP/DIP joints) Extensor digitorum Posterior interosseous n.
Extensor indicis Posterior interosseous n.
EXTENSION (MP/PIP/DIP joints) Flexor digiti minimi Posterior interosseous n.
EXTENSION (PIP/DIP joints) Lumbricals I and II usually Median n.
Lumbricals III and IV ususally Ulnar n.
ABDUCTION Dorsal interossei Ulnar n.
ABDUCTION (thumb fixed) Abductor pollicis brevis Median n.
ABDUCTION Abductor digiti minimi Ulnar n.
ADDUCTION Palmar interossei Ulnar n.
OPPOSITION Opponens digit minimi Ulnar n.
THUMB FLEXION (IP joint) Flexor pollicis longus Anterior interosseous n.
FLEXION/ROTATION (MP joint) Flexor pollicis brevis Median n. and/or ulnar n.


EXTENSION (MP joint) Extensor pollicis brevis Posterior interosseous n.
EXTENSION (IP joint) Extensor pollicis longus Posterior interosseous n.
ABDUCTION Abductor pollicis longus Posterior interosseous n.
ABDUCTION/ROTATION Abductor pollicis brevis Median n.
ADDUCTION/ROTATION Adductor pollicis Ulnar n.
ADDUCTION/FLEXION (MP joint) Palmar interosseous I Ulnar n.
OPPOSITION Opponens pollicis Median n. and ulnar n.
Muscles and movements that have diagnostic value are marked in red. Spinal roots have been given the same colour (light peach, dark peach, red) when they innervate a muscle to a similar extent. Red has been used to
indicate roots from which there is known to be a dominant contribution.
*These movements occur at the radio-ulnar joints.
Abbreviations: DIP, distal interphalangeal; IP, interphalangeal; MP, metacarpophalangeal; PIP, proximal interphalangeal.


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Table 46.2 Segmental innervation of the muscles of the upper limb Table 46.3 Segmental innervation of joint movements of the upper limb
Nerves Muscles Territory Muscles Nerves
C3, 4 Trapezius, levator scapulae Shoulder Abductors and lateral rotators C5
C5 Rhomboids, deltoids, supraspinatus, infraspinatus, teres minor, biceps Adductors and medial rotators C6–8
C6 Serratus anterior, latissimus dorsi, subscapularis, teres major, pectoralis major Elbow Flexors C5, 6
(clavicular head), biceps, coracobrachialis, brachialis, brachioradialis, supinator, Extensors C7, 8
extensor carpi radialis longus Forearm Supinators C6
C7 Serratus anterior, latissimus dorsi, pectoralis major (sternal head), pectoralis Pronators C7, 8
minor, triceps, pronator teres, flexor carpi radialis, flexor digitorum superficialis, Wrist Flexors and extensors C6, 7
extensor carpi radialis longus, extensor carpi radialis brevis, extensor digitorum, Digits Long flexors and extensors C7, 8
extensor digiti minimi
Hand Intrinsic muscles C8, T1
C8 Pectoralis major (sternal head), pectoralis minor, triceps, flexor digitorum
superficialis, flexor digitorum profundus, flexor pollicis longus, pronator quadratus,
flexor carpi ulnaris, extensor carpi ulnaris, abductor pollicis longus, extensor
pollicis longus, extensor pollicis brevis, extensor indicis, abductor pollicis brevis,
flexor pollicis brevis, opponens pollicis
T1 Flexor digitorum profundus, intrinsic muscles of the hand (except abductor pollicis


brevis, flexor pollicis brevis, opponens pollicis)
Table 46.4 Movements and muscles tested to determine the location of a lesion in the upper limb
Arm movement Muscle Upper motor neurone Root Reflex Nerve
Shoulder abduction Deltoid ++ C5 Axillary
Elbow flexion Biceps C5/6 + Musculocutaneous
Brachioradialis C6 Radial
Elbow extension Triceps + C7 + Radial
Radial wrist extensor Extensor carpi radialis longus + C6 Radial
Finger extensors Extensor digitorum + C7 (+) Posterior interosseous
Finger flexors Flexor pollicis longus and flexor digitorum profundus, index C8 + Anterior interosseous
Flexor digitorum profundus, ring and little Ulnar
Finger abduction First dorsal interosseous ++ T1 Ulnar
Abductor pollicis brevis T1 Median
The muscles listed in the ‘Upper motor neurone’ column are those that are preferentially affected in upper motor neurone lesions. The root level is the principal supply to a muscle.
In the acute injury, the object of the clinician must be to recognize the the shaft of the humerus. The median, ulnar and radial nerves may be
fact of injury as soon as possible after the event, and later, to go on to subjected to traction, or entrapment, by fracture or dislocation about
determine the nerve or nerves affected, the level(s) of injury, and the the elbow. The median nerve is severely compressed by fractures or
extent and depth of the lesion(s). The history is important: high injury dislocations impinging into the carpal tunnel. All nerves may be
transfer, open fracture and wounding (be it accidental, criminal, surgi transected by wounds from a knife, glass, a bullet or other missile any
cal, or all three) indicate a serious lesion and advice from witnesses or where along their course. The axillary artery and its main branches are
emergency paramedical staff is always valuable. Injuries that are poten commonly involved in nerve injuries. Wounds of the median nerve in
tially life or limbthreatening complicate closed traction lesions of the the arm commonly extend to the brachial artery, and the ulnar artery


supraclavicular brachial plexus in about 20% of cases. It is important is usually involved in wounds to the ulnar nerve in the forearm and at
to seek occult injuries to the head, spine, thorax, abdomen and pelvis the wrist.
before embarking on treatment of the nerve lesion(s). Nerves and related structures may be displaced by fracture, disloca
The early symptoms of acute nerve injury include: abnormal spon tion or haematoma. The ensuing fibrosis distorts normal anatomical
taneous sensations; alteration or loss of sensibility; weakness and par relations; this increases the risk of intraoperative damage when nerves
alysis; impairment of function; an awareness of warming and dryness and accompanying vessels are not formally exposed. The incidence of
of all or part of an extremity (sometimes); and pain (sometimes). Neu such iatrogenic injuries is increasing, accounting for onequarter of
ropathic pain is never easy to recognize in an injured patient, who is lesions of the radial nerve; the incidence is even higher for nerves
probably confused, distressed and in pain. It can be distinguished from around the elbow.
the pain of fracture or dislocation by loss of sensation; painful, spon Injuries to nerves of cutaneous sensation are common after wounds,
taneous sensory symptoms, expressed throughout the territory of the incisions or vessel puncture. It is remarkable that the elective removal
nerve; and by lancinating or shooting pain, irradiating into the distribu of nerves such as the medial cutaneous nerve of the forearm for the
tion of the nerve. Constant crushing, bursting or burning pain in an purpose of grafting is followed by pain only very rarely, while lesions
otherwise undamaged hand indicates serious and continuing injury to of the terminal branches are usually painful. The medial cutaneous
major trunk nerves more proximally. Progression of sensory loss, with nerve of the arm and the intercostobrachial nerve are at risk during
a deep bursting or crushing pain within the muscles of the limb, signi operations in the axilla. The posterior cutaneous nerves of the arm and
fies critical ischaemia. forearm are vulnerable during the lateral approach to the shaft of the
humerus. The medial and lateral cutaneous nerves of the forearm are
The main nerves are stretched, ruptured or avulsed from muscle by frequently damaged during operations around the elbow. The dorsal


violent hyperextension–abduction injuries of the arm. The axillary or branch of the ulnar nerve is at risk during operations on the distal third
brachial artery is ruptured in at least onethird of fractures of the proxi of the ulna. The superficial radial and lateral cutaneous nerves are fre
mal humerus or fracture dislocations of the shoulder. The axillary nerve quently injured by interventions on the lateral side of the wrist. Injuries
and posterior circumflex vessels, which pass almost horizontally pos to the palmar cutaneous branch of the median nerve and to the digital
terior to the neck of the humerus, are particularly at risk from anterior nerves are unwelcome complications of operations on the hand. These
dislocation of the head of the humerus. The radial nerve and the pro injuries cause pain, which may become severe. Mechanical allodynia,
funda brachii artery are relatively fixed where they pass from the the perception of light touch as pain, is common; the spread of pain
anterior to the posterior compartment by perforating the medial inter and allodynia beyond the territory of an injured nerve is frequent and
muscular septum in the axilla, and again when they reemerge into the indicates central sensitization of other neurones in the dorsal horn of
anterior compartment by perforating the lateral intermuscular septum. the spinal cord.
They may be stretched, ruptured or entrapped by displaced fractures of


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EXAMINATION
Examination complements the history and the interpretation of symp
toms to provide an accurate diagnosis. All findings should be set down
in an intelligible record. Unfortunately, the signs of acute nerve injury
have to be sought at a time when the patient may be least able to
cooperate in an examination: soon after wounding, when there is likely
to be distress and when the general condition may be affected by loss
of blood and other injuries and/or by drink and drugs. The examination
often has to be undertaken in the frequently unfavourable surroundings
of an accident department. When the lesion has been inflicted by a
surgeon or anaesthetist, the patient’s response is likely to be distorted
by postoperative pain, by the effects of recent general anaesthesia or by
sedative or analgesic drugs. These are inappropriate conditions for a
quiet and comprehensive ‘neurological examination’, and yet this is the
time when the fact of nerve injury must at least be recognized if the
best result is to be obtained from treatment. The examiner should, at
all times, bear in mind the fact that, if there is a wound over the line
of a main nerve and if there is any suggestion of loss of sensibility Fig . 46 .18 The area of sensory abnormality after section of the lateral
cord in the axilla . As in Figure 46 .17, there was no complete loss of
or impairment of motor function in the distribution of that nerve, it
sensation . (Courtesy of Rolfe Birch, all rights reserved, published in Birch
must be regarded as having been cut until and unless it is proved
R, Surgical Disorders of the Peripheral Nerve, 2nd ed, 2011 . Springer-
otherwise.
Verlag, London .)
Local signs in closed injury
In closed injuries, swelling or ecchymosis and linear abrasions indicate
severe soft tissue injury and also the line of application of force (see
Fig. 6.1.1 in Commentary 6.1). Peripheral pulses and limb perfusion
must be examined and reexamined.
Wound characteristics
It is useful to distinguish between the tidy wound caused by a knife and
the untidy, and usually contaminated, wound of open fracture, machin


ery or gunshot. A further distinction is made between wounds caused
by a handgun, rifle and closerange shotgun, the latter being particularly
destructive. The injuries of current conflicts are classed as: penetrating
missile wound, (small) fragment wound, and blast wound, those from
mines or improvised explosive devices (IEDs).
Sensation
Sensory loss is determined by response to light touch and pinprick. If
circumstances permit, the patient outlines the area of sensory loss,
which is then marked by a black skinmarker pen. The surrounding
zone of incomplete sensory loss can be similarly marked in red,
Fig . 46 .19 Rupture of the posterior divisions of the trunks of the brachial
and the limb then photographed. For clinical examples, see Figures plexus deep to the clavicle . (Courtesy of Rolfe Birch, all rights reserved,
46.17–46.27. published in Birch R, Surgical Disorders of the Peripheral Nerve, 2nd ed,
Examination of muscles 2011 . Springer-Verlag, London .)
Selected muscles are examined. The patient lying supine is usually able
to demonstrate activity in serratus anterior by lifting the shoulders away
from the couch, by means of ‘forward shrugging’. It is usually possible
to observe the presence of flexion and abduction at the shoulder, flexion
Fig . 46 .17 The area of sensory abnormality after transection of C8 and T1 . Fig . 46 .20 Rupture of the axillary nerve . (Courtesy of Rolfe Birch, all rights
(Courtesy of Rolfe Birch, all rights reserved, published in Birch R, Surgical reserved, published in Birch R, Surgical Disorders of the Peripheral Nerve,
Disorders of the Peripheral Nerve, 2nd ed, 2011 . Springer-Verlag, London .) 2nd ed, 2011 . Springer-Verlag, London .)


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B
Fig . 46 .21 Sensory loss in two cases of rupture of the musculocutaneous
nerve . Both patients were able to supinate the forearm fully; the power of
elbow flexion was around 30% . (Courtesy of Rolfe Birch, all rights
A reserved, published in Birch R, Surgical Disorders of the Peripheral
Nerve, 2nd ed, 2011 . Springer-Verlag, London .)
B
Fig . 46 .22 A–B, Two examples of high lesion of the radial nerve . In B,
there is early recovery into the wrist extensors after repair . (Courtesy of
A Rolfe Birch, all rights reserved, published in Birch R, Surgical Disorders of
the Peripheral Nerve, 2nd ed, 2011 . Springer-Verlag, London .)


Pectoral girdle and upper limb: overview and surface anatomy
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A
Fig . 46 .25 Section of the median nerve and the palmar cutaneous nerve
at the wrist . (Courtesy of Rolfe Birch, all rights reserved, published in
Birch R, Surgical Disorders of the Peripheral Nerve, 2nd ed, 2011 .
Springer-Verlag, London .)
B
Fig . 46 .23 A–B, Transection of the median nerve, ulnar nerve, medial
cutaneous nerve of the forearm, and brachial artery, in the arm of a and extension of the elbow and wrist, and flexion and extension of
14-year-old boy . Note the extent of skin innervation provided by the the fingers. The radial, median and ulnar nerves are tested by asking the
superficial radial and lateral cutaneous nerves of the forearm . The intact patient to form an ‘O’ between the thumb and little finger, to give
radial nerve permits a sort of grasp . (Courtesy of Rolfe Birch, all rights the ‘thumbs up’ sign, and to open and close the fingers like a fan. The
reserved, published in Birch R, Surgical Disorders of the Peripheral Nerve, palmar skin is scrutinized for changes in colour and in sweating (Fig.
2nd ed, 2011 . Springer-Verlag, London .) 46.28). Although this may be more difficult in pigmented skin, such
changes are detectable. The standard tendon reflexes are examined.
Secondary examination
A more detailed examination is possible when the patient’s condition
is stable, and when pain has been controlled. Limb dominance, occupa
tion, marital status, underlying disease and continuing medication are
recorded, if this has not already been done. Neuropathic pain is now
somewhat easier to recognize because it is less responsive to analgesics
than is pain from skeletal injury.
Recognition of the level of a lesion and the
depth of injury
A sound grasp of the distribution of the spinal nerves and of the loca
tion of the formation and branching of the trunk nerves allows accurate
diagnosis of the level of a lesion.
Posterior cord and radial nerve
The extent of the sensory loss is variable. There is no cutaneous sensory
loss in lesions confined to the posterior interosseous nerve. The exami


nation of selected muscles is reliable in guiding the clinician to the
level of injury. They include, in order: teres major (inferior scapular
nerve), latissimus dorsi (thoracodorsal nerve) and deltoid (axillary
nerve). Subscapularis (superior scapular nerve) is not an easy muscle to
examine.
Paralysis of all three heads of triceps places the injury in the axilla.
The nerves to the lateral head of triceps leaves the main nerve rather
distally, so that radial palsy, with paralysis of the lateral head but active
medial and long heads, points to a lesion in the spiral groove. The
nerve to brachioradialis consistently passes away from the main trunk
about three fingers’breadths above the lateral epicondyle, and the
nerve to extensor carpi radialis longus leaves the main trunk about 1 cm
Fig . 46 .24 A high median nerve injury; there is no active flexion of the more distally. One nerve to extensor carpi radialis brevis leaves the main
index finger and thumb . (Courtesy of Rolfe Birch, all rights reserved, nerve about 1 cm proximal to the lateral epicondyle, and another leaves
published in Birch R, Surgical Disorders of the Peripheral Nerve, 2nd ed, at the site of division into the superficial radial and posterior interos
2011 . Springer-Verlag, London .) seous nerves.


PECTOral GIrdlE aNd UPPEr lImb: OvErvIEw aNd SUrfaCE aNaTOmy
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A B
Fig . 46 .26 A–B, A typical area of loss of sensibility after division of the median nerve at the wrist, sparing the palmar cutaneous branch . (Courtesy of
Rolfe Birch, all rights reserved, published in Birch R, Surgical Disorders of the Peripheral Nerve, 2nd ed, 2011 . Springer-Verlag, London .)
Fig . 46 .27 The area of sensory loss and ‘clawing’ of
little and ring fingers after division of the ulnar nerve
in the forearm . (Courtesy of Rolfe Birch, all rights
reserved, published in Birch R, Surgical Disorders of
the Peripheral Nerve, 2nd ed, 2011 . Springer-Verlag,
London .)
A B
Fig . 46 .28 Sympathetic paralysis seen within
a few days of transection . A, B, Transection
of the median nerve at the elbow . (Courtesy
of Rolfe Birch, all rights reserved, published
in Birch R, Surgical Disorders of the
Peripheral Nerve, 2nd ed, 2011 . Springer-
Verlag, London .)
A B


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lateral cord, musculocutaneous nerve and lateral vibration sense and sensibility to light touch are likely to be impaired,
root of the median nerve whereas pain sensibility may be unaffected. There is a risk of under
estimating the severity of a nerve lesion in cases of closed injury and
It seems that most of the median nerve fibres that innervate the skin
after intraoperative events. Different populations of nerve fibres within
of the hand pass through the lateral cord. Paralysis involves biceps
a main nerve that has been violently stretched but not ruptured sustain
brachii, brachialis, flexor carpi radialis and pronator teres. That portion
lesions of all grades of severity. Some remain intact, whilst conduction
of brachialis innervated by the radial nerve may be intact. Division of
is blocked in others. Some ruptured axons will recover spontaneously,
the musculocutaneous nerve does not lead to loss of elbow flexion
whilst others will not, depending on their cellular microenvironment
because brachioradialis acts as a powerful flexor of the joint (see
(see Commentary 1.6).
Fig. 46.21).
Testing of sensibility is often difficult soon after wounding, or when
medial cord, medial head of the median nerve injury is associated with fracture of a long bone. The actions of
and ulnar nerves some muscles can be simulated by the actions of others, so that the fact
of paralysis can be missed in the early stages after nerve injury. Thus,
The sensory loss does not extend into the arm. If it does, then the
when the median nerve has been cut, opposition of the thumb can be
medial cutaneous nerve of the arm must be involved. Paralysis is exten
mimicked by the action of extensor pollicis brevis (ulnar nerve) and
sive, and includes the long flexor muscles to the digits, the small muscles
abductor pollicis longus (radial nerve). Similarly, abductor pollicis
of the hand, and the smooth muscle associated with the vessels and
longus can imitate the action of the abductor pollicis brevis. It is impor
sweat glands supplying the ulnar three fingers.


tant to examine both hands, especially in the early days, when there is
median nerve no wasting to guide the examiner. One almost infallible sign is always
present in the first 48 hours after deep injury of a nerve with a cutane
Involvement of the palmar cutaneous nerve is useful in localizing a
ous sensory component: because small, as well as large, fibres are
lesion at the wrist (see Figs 46.25, 46.26), but the extent of paralysis is
affected, the skin in the distribution of the damaged nerve is warm and
a more precise guide to the level of a lesion. Injuries in the arm cause
dry. In a small child, there may be an abnormal posture of the denerv
paralysis of all muscles innervated by the median nerve, including those
ated digits; the ‘immersion test’ is also helpful. The injured hand or foot
arising from the medial epicondyle (flexor carpi radialis, pronator teres,
is placed, for a few minutes, in warm water; the skin of the denervated
palmaris longus, and part of flexor digitorum superficialis), as well as
digits fails to wrinkle. In ischaemia, the large fibres conveying discrimi
those innervated by the anterior interosseous nerve (flexor pollicis
native sensibility and vibration sense are first affected. It is not easy to
longus, flexor digitorum profundus to index finger) (see Fig. 46.24).
test these modalities when ischaemia is developing because of the
Anterior interosseous palsy is distinguished from high median injury
damage to a main vessel that is associated with a fracture of a long bone,
by the absence of any loss of skin sensation. Abductor pollicis brevis is
but if action is not taken until superficial sensibility is lost, it will come
the one small muscle of the hand that is consistently innervated by the
too late.
median nerve.
Ulnar nerve Tinel’s sign
The sensory loss is related to the involvement of the dorsal and palmar
cutaneous branches (see Fig. 46.27). Ulnar palsy with paralysis of flexor In closed injuries, percussion of the skin over a nerve in which axons