by dividing into the radial and ulnar arteries (see Figs 48.33, 48.44, the brachial artery to the axillary artery or to one of the forearm arteries,
49.21, 49.22). At first, it is medial to the humerus, but gradually spirals usually the radial. The brachial artery may be crossed by muscular or
anterior to it until it lies midway between the humeral epicondyles. Its tendinous slips from coracobrachialis, biceps brachii, brachialis or pro
pulsation can be felt throughout the arm. nator teres. Rarely, the median nerve crosses posterior, rather than an
terior, to the brachial artery near the insertion of coracobrachialis.
Relations The brachial artery is wholly superficial, covered anteriorly
only by skin and superficial and deep fasciae. The bicipital aponeurosis Branches The branches of the brachial artery are the profunda
crosses it anteriorly at the elbow, separating it from the median cubital brachii, nutrient, superior, middle and inferior ulnar collateral, deltoid,
vein; the median nerve crosses it lateromedially near the distal attach muscular, radial and ulnar arteries.
ment of coracobrachialis. Posterior to the artery are the long head
of triceps, separated by the radial nerve and profunda brachii artery, Profunda brachii artery The profunda brachii (Fig. 48.33; see Figs
and then successively by the medial head of triceps, the attachment 48.29, 48.31) is a large branch from the posteromedial aspect of the
Superior transverse scapular ligament Fig. 48.33 Muscles, vessels and nerves of
Suprascapular nerve the left upper arm, posterior aspect. (With
Suprascapular artery
permission from Waschke J, Paulsen F (eds),
Sobotta Atlas of Human Anatomy, 15th ed,
Elsevier, Urban & Fischer. Copyright 2013.)
Inferior transverse
scapular ligament
Circumflex scapular
Deltoid
artery
Axillary nerve
Posterior circumflex
humeral artery
Brachial artery
Radial nerve
Posterior cutaneous nerve
Profunda brachii artery


Lateral head of triceps
Radial collateral artery, posterior branch
Medial head of triceps
Lateral cutaneous
nerve of the forearm Inferior ulnar collateral artery
Ulnar nerve
Recurrent ulnar artery


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The potential vascular anastomoses around the shoulder girdle are
numerous, so that collateral perfusion of the upper limb is possible in
axillary artery or vein occlusion. In acute occlusion of the axillary artery,
these potential anastomoses are not reliable; clinicians should not rely
on anastomotic perfusion of the acutely ischaemic limb. The axillary
artery is most ‘at risk’ of occlusion due to intimal separation and dis
section in its second part, behind the pectoralis minor. This injury is
associated with infraclavicular brachial plexus traction lesions (Birch
2011). Although magnetic resonance imaging (MRI) with angiography
is recommended for the diagnosis of the poorly perfused limb after
distraction trauma, the site of intimal rupture is so consistent as to make
urgent surgical exploration without imaging a reasonable clinical
decision.
The axillary artery supplies the muscles of the ventral compartments of
the shoulder, including the pectoral–deltoid muscle sheet, the scapulo
humeral muscles (other than the posterosuperior rotator cuff) and the
shoulder joint, including the scapula (with the serratus muscles) and
proximal humerus. Its terminal branch, the brachial artery, supplies the
muscles of the anterior compartment of the arm (for the branches of
the brachial artery at the elbow and in the forearm, see pages 856–858);
the profunda brachii artery, the major proximal branch of the brachial
artery, supplies the muscles of the posterior compartment of the arm
and the shaft of the humerus.


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brachial artery, distal to teres major. It follows the radial nerve closely, VEINS
at first posteriorly between the long and medial heads of triceps, then
in the spiral groove covered by the lateral head of triceps. It supplies The deep veins have numerous anastomoses with each other and with
muscular branches, and the nutrient artery of the humerus, and finally the superficial veins.
divides into terminal radial and middle collateral branches (see Fig.
48.33). The radial collateral branch pierces the lateral intermuscular
Axillary vein
septum to reach the anterior aspect of the epicondyle of the humerus
in the groove between brachioradialis and brachialis, and takes part in
the anastomosis around the elbow. The middle collateral branch runs The axillary vein is the continuation of the basilic vein (see Fig. 46.4).
posterior to the septum and epicondyle. It begins at the lower border of teres major and ascends to the outer
The profunda brachii may originate from a common origin with the border of the first rib, where it becomes the subclavian vein. It is joined
posterior circumflex humeral artery, from the axillary artery proximal by the brachial vein near subscapularis, and by the cephalic vein near
to the tendon of latissimus dorsi, or from the distal portion of the axil its costal end; other tributaries follow the axillary arterial branches. It
lary artery. lies medial to the axillary artery, which it partly overlaps. The medial
pectoral nerve, medial cord of the brachial plexus, ulnar nerve and
Middle collateral (posterior descending) branch The middle collat medial cutaneous nerve of the forearm lie between the artery and the
eral artery is the larger terminal branch of the profunda brachii artery. vein. The medial cutaneous nerve of the arm is medial to the vein; the
It arises posterior to the humerus and descends along the posterior lateral group of axillary lymph nodes is posteromedial. There are a pair
surface of the lateral intermuscular septum to the elbow. Proximally, of valves near its distal end, and valves also occur near the ends of the


the artery lies between brachialis (anteriorly) and the lateral head of cephalic and subscapular veins.
triceps (posteriorly). Distally, it lies between brachioradialis (anteriorly)
and the lateral head of triceps (posteriorly). It may pierce the deep fascia Subclavian vein
and become cutaneous, or remain deep to the fascia until it anastomo
ses with the interosseous recurrent artery behind the lateral epicondyle; The subclavian vein is a continuation of the axillary vein (see Fig. 46.4).
it gives off about five small fasciocutaneous perforators and often has It extends from the outer border of the first rib to the medial border of
a small branch that accompanies the nerve to anconeus. scalenus anterior, where it joins the internal jugular to form the bra
chiocephalic vein. The clavicle and subclavius are anterior; the subcla
Radial collateral (anterior descending) branch The radial collateral vian artery is posterosuperior, separated by scalenus anterior and the
artery accompanies the radial nerve through the lateral intermuscular phrenic nerve; and the first rib and pleura are inferior. The vein usually
septum, descending between brachialis and brachioradialis anterior to has a pair of valves about 2 cm from its end. Its tributaries are the
the lateral epicondyle and anastomosing with the radial recurrent artery external jugular, dorsal scapular and (sometimes) anterior jugular veins,
(see Figs 49.29, 49.31). It supplies brachialis, brachioradialis, the radial and, occasionally, a small branch from the cephalic vein that ascends
nerve and a few fasciocutaneous perforators. anterior to the clavicle. At its junction with the internal jugular vein,
the left subclavian receives the thoracic duct, and the right subclavian
Nutrient artery of humerus The nutrient artery of the humerus vein receives the right lymphatic duct (see Fig. 29.16).
arises near the midlevel of the upper arm and enters the nutrient canal
near the attachment of coracobrachialis, posterior to the deltoid tuber Brachial veins
osity; it is directed distally.


The brachial veins flank the brachial artery, as venae comitantes with
Superior ulnar collateral artery The superior ulnar collateral
tributaries similar to the arterial branches; they join the axillary vein
artery arises a little distal to the midlevel of the upper arm, usually
near the lower margin of subscapularis. The medial branch often joins
from the brachial artery, but often as a branch from the profunda
the basilic vein before it becomes the axillary vein.
brachii (see Fig. 48.44). It accompanies the ulnar nerve, piercing the
medial intermuscular septum to descend in the posterior compartment Superficial veins
and supply the medial head of triceps. It passes between the medial
epicondyle and olecranon, ending deep to flexor carpi ulnaris by anas
tomosing with the posterior ulnar recurrent and inferior collateral arter The cephalic vein ascends anterior to the elbow, superficial to a groove
ies. A branch sometimes passes anterior to the medial epicondyle and between brachioradialis and biceps brachii, crosses superficial to the
anastomoses with the anterior ulnar recurrent artery. lateral cutaneous nerve of the forearm, and ascends lateral to biceps
and between pectoralis major and deltoid, where it adjoins the deltoid
Middle ulnar collateral artery If present, the middle ulnar col branch of the thoracoacromial artery (Fig. 48.34). Entering the infra
lateral artery arises from the brachial artery between the superior and clavicular fossa to pass posterior to the clavicular head of pectoralis
inferior ulnar collateral arteries. It passes anterior to the medial epi major, it pierces the clavipectoral fascia, crosses the axillary artery and
condyle and anastomoses with the anterior ulnar recurrent artery. joins the axillary vein just below clavicular level. It may connect with
It supplies triceps and sends small fasciocutaneous perforators to the the external jugular vein by a branch anterior to the clavicle. Sometimes,
skin. the median cubital vein is large, transferring most blood from the
cephalic to the basilic vein, in which case the proximal cephalic vein is


Inferior ulnar collateral (supratrochlear) artery The inferior either absent or much diminished.
ulnar collateral artery begins approximately 5 cm proximal to the
elbow, passes medially between the median nerve and brachialis, and,
LYMPHATIC DRAINAGE
piercing the medial intermuscular septum, curls round the humerus
between triceps and bone (see Fig. 48.33). By its junction with the
middle collateral branch of the profunda brachii artery, it forms an arch Lymphatics follow the usual pattern, in that superficial lymphatics
proximal to the olecranon fossa. As it lies on brachialis, it gives off follow the veins, and deep lymphatics follow the arteries. For details of
branches that descend anterior to the medial epicondyle to anastomose the infraclavicular nodes, see Fig. 48.45 and page 834.
with the anterior ulnar recurrent artery. Behind the epicondyle, a branch
anastomoses with the superior ulnar collateral and posterior ulnar
INNERVATION
recurrent arteries.
Muscular branches Muscular branches are distributed to coraco BRACHIAL PLEXUS
brachialis, biceps and brachialis.
For an overview of the brachial plexus, see pages 781786 and
Deltoid (ascending) branch The deltoid branch ascends between the Figure 46.7.
lateral and long heads of triceps, and anastomoses with a descending In the axilla, the lateral and posterior cords of the brachial plexus
branch of the posterior humeral circumflex artery. are anterior and lateral to the first part of the axillary artery, respectively,
and the medial cord is behind the artery. The cords assume their appro
Radial and ulnar arteries The radial and ulnar arteries are described priate relations around the second part of the artery, deep to pectoralis
in detail on page 856 and 857, respectively. For an account of the anas major. In the lower axilla, the cords divide into nerves that supply the
tomosis about the elbow, see page 858. upper limb (Fig. 48.35). Other than the medial root of the median


innervation
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Medial pectoral nerve
Lateral
supraclavicular The medial pectoral nerve (C8, T1) branches from the medial cord while
nerves the latter lies posterior to the axillary artery and curves forwards between
the axillary artery and vein. Anterior to the artery, it joins a ramus of
the lateral pectoral nerve and enters the deep surface of pectoralis minor,
which it supplies. Two or three branches pierce pectoralis minor and
others may pass round its inferior border to end in pectoralis major.
Upper (superior) subscapular nerve
The superior subscapular nerve is smaller than the inferior. It arises
Intercosto- from the posterior cord (C5, 6), enters subscapularis at a high level,
brachial nerve and is frequently double.
Medial cutaneous Lower (inferior) subscapular nerve
nerve of arm
The inferior subscapular nerve arises from the posterior cord (C5, 6). It
Cephalic vein supplies the lower part of subscapularis and ends in teres major, which
is sometimes supplied by a separate branch.
Thoracodorsal nerve
The thoracodorsal nerve arises from the posterior cord (C6–8) between
the subscapular nerves. It accompanies the subscapular artery along the
posterior axillary wall and supplies latissimus dorsi, reaching its distal
border (see Fig. 48.29).
Medial cutaneous
Axillary nerve
nerve of forearm
The axillary nerve arises from the posterior cord (C5, 6) (see Figs 48.33,
Basilic vein 48.35, 46.8). It is, at first, lateral to the radial nerve, posterior to the
Medial cutaneous Lateral cutaneous axillary artery and anterior to subscapularis. At the lower border of
nerve of forearm,
nerve of forearm subscapularis, it curves back inferior to the humeroscapular articular
posterior branch
Median cubital vein capsule and, with the posterior circumflex humeral vessels, traverses a
Medial cutaneous quadrangular space bounded above by subscapularis (anteriorly) and


nerve of forearm, Posterior cutaneous teres minor (posteriorly), below by teres major, medially by the long
anterior branch nerve of forearm head of triceps, and laterally by the surgical neck of the humerus. It
divides in the space into anterior and posterior branches. The anterior
Median vein of forearm branch curves round the neck of the humerus with the posterior cir
cumflex humeral vessels, deep to deltoid, to reach the anterior part of
the muscle. At the level of the anterior border of the acromion, the nerve
often consists of two or more thin filaments that supply the anterior
deltoid; it gives off a few small cutaneous branches that pierce deltoid
Fig. 48.34 Superficial veins and nerves, left arm, anterior (flexor) aspect. and ramify in the skin over its lower part. The posterior branch courses
(With permission from Waschke J, Paulsen F (eds), Sobotta Atlas of medially and posteriorly along the attachment of the lateral head of
Human Anatomy, 15th ed, Elsevier, Urban & Fischer. Copyright 2013.)
triceps, inferior to the glenoid rim. It usually lies medial to the anterior
branch in the quadrangular space. It gives off the nerve to teres minor
and the upper lateral cutaneous nerve of the arm at the lateral edge of
nerve, these nerves are related to the third part of the artery in the same the attachment of the long head of triceps. The nerve to teres minor
way as their cords are related to the second part, i.e. branches of the enters the muscle on its inferior surface. The posterior branch frequently
lateral cord are lateral to the artery, branches of the medial cord are supplies the posterior aspect of deltoid, usually via a separate branch
medial, and branches of the posterior cord are posterior. from the main stem, but occasionally from the superior lateral cutane
ous nerve of the arm. However, the posterior part of deltoid has a more
Suprascapular nerve
consistent supply from the anterior branch of the axillary nerve, which
should be remembered when performing a posterior deltoidsplitting
The suprascapular nerve is a large branch of the upper trunk (C5, 6) approach to the shoulder. The upper lateral cutaneous nerve of the arm


(see Figs 29.17, 48.35). It runs laterally, deep to trapezius and omohy pierces the deep fascia at the medial border of the posterior aspect of
oid, and enters the supraspinous fossa through the suprascapular notch deltoid, and supplies the skin over the lower part of deltoid and the
inferior to the superior transverse scapular ligament. It runs deep to upper part of the long head of triceps. The posterior branch is intimately
supraspinatus, supplies it, and curves round the lateral border of the related to the inferior aspects of the glenoid and shoulder joint capsule.
spine of the scapula with the suprascapular artery to reach the infrasp There is often an enlargement or pseudoganglion on the branch to teres
inous fossa, where it gives two branches to infraspinatus and articular minor. The axillary trunk supplies a branch to the shoulder joint below
rami to the shoulder and acromioclavicular joints. The suprascapular subscapularis.
nerve rarely has a cutaneous branch. When present, it pierces deltoid
close to the tip of the acromion and supplies the skin of the proximal
Injuries to the shoulder girdle involving the
third of the arm within the territory of the axillary nerve.
accessory, long thoracic, axillary and
Lateral pectoral nerve suprascapular nerves
The lateral pectoral nerve (C5, 6) is larger than the medial, and may arise Available with the Gray’s Anatomy e-book
either from the anterior divisions of the upper and middle trunks, or by
a single branch from the lateral cord, just above or deep to the clavicle.
Musculocutaneous nerve
It crosses anterior to the axillary artery and vein, pierces the clavipectoral
fascia and supplies the deep surface of pectoralis major. It sends a
branch to the medial pectoral nerve, forming a loop in front of the first The musculocutaneous nerve arises from the lateral cord (C5–7), oppo
part of the axillary artery to supply some fibres to pectoralis minor. site the lower border of pectoralis minor (Fig. 48.44; see Figs 46.13,


Shoulder girdle and arm
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Diagnosis of injuries to the accessory, long thoracic, axillary and supra after successful thoracoscapular arthrodesis in scapulohumeral dystro
scapular nerves is by no means straightforward; serious mistakes are phy (Copeland and Howard 1978). This range of movement occurs at
most common in the diagnosis of severe injuries about the shoulder the shoulder joints, mainly the glenohumeral joint, with some involve
girdle. The delay before diagnosis is inexplicable despite the reliability ment of the acromioclavicular and sternoclavicular joints. Successful
of precise but elementary clinical examination. Matters are not helped glenohumeral arthrodesis enables a range of elevation of 30–40°; this
by the persistence with which incorrect and discredited ideas about is provided by the thoracoscapular joint.
what muscles do continue to be taught. Many nerve injuries in this
Accessory nerve
region are painful and, too often, a patient is passed to a pain clinic
without a diagnosis. The integrity of the accessory nerve is fundamental to thoracoscapular
function and essential for scapulohumeral rhythm. The nerve is usually
Inferior scapulohumeral angle (ISHA)
divided at the apex of the posterior triangle, usually by surgeons, and
Assessing the inferior scapulohumeral angle (ISHA) informs the clini is a crippling injury. Typically, there is immediate pain, then dropping
cian about function at the thoracoscapular and shoulder joints (Fig. of the shoulder and a remarkable loss of function. The average ISHA is
48.36). The ISHA is subtended by the long axis of the humerus and the about 50°. The pain is characteristic: often severe, deepseated, dull,
lateral border of the scapula; the apex of the angle is centred over the constant and boring in nature, and felt around the scapula and the
glenohumeral joint. Stiffness of the joints is detected by measuring posterior aspect of the neck and shoulder. The posture of the scapula
passive range, which is normally between 170° and 180°. The excursion is also characteristic: because of the loss of the great suspensory muscle,


between the humerus and the scapula in a healthy adult is between trapezius, the scapula drops down and away from the spinal column
130° and 140°: that is, the difference between the ISHA at rest and in (Fig. 48.37). There is often winging of the scapula, which is easily
full elevation. It is important to remember that full elevation is possible distinguished from that caused by paralysis of serratus anterior by the
A B
Fig. 48.36 The active inferior scapulohumeral angle (ISHA) in a normal shoulder is about 170°. A, At rest. B, Arm abducted. (Courtesy of Rolfe Birch, all
rights reserved, published in Birch R, Surgical Disorders of the Peripheral Nerve, 2nd ed, 2011. Springer-Verlag, London.)
A
Fig. 48.37 A right accessory palsy. A, At rest. B, Attempted abduction.
The scapula drops down and away from the spine. The active ISHA is
30°. (Courtesy of Rolfe Birch, all rights reserved, published in Birch R,
Surgical Disorders of the Peripheral Nerve, 2nd ed, 2011. Springer- B
Verlag, London.)


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Dislocation of the shoulder: the
suprascapular and axillary nerves
Although most nerve lesions in uncomplicated anterior dislocations are
benign, it is well to remember the risk to adjacent vessels, more so in
highenergy transfer injuries, in older patients and in those with periph
eral vascular disease. The consequences of delay in treatment are severe.
It is very hard to examine muscles in a patient with a fracture disloca
tion of the shoulder. Sensory loss is inconsistent. Consider, for example,
a patient after successful reduction of a dislocated shoulder, whose arm
is supported in a sling. There are three simple tests: initiation of abduc
tion shows that the suprascapular nerve is intact and that the rotator
cuff is not ruptured; abnormal sensibility in the skin over deltoid indi
cates a lesion of the axillary nerve; and gentle extension of the shoulder
on the part of the patient, supported as it is in a sling, means that
the examiner can palpate activity in the posterior fibres of deltoid (Figs
48.40–48.41).
The diagnosis of nerve injury is by no means straightforward. All too
often, rupture of the axillary nerve is not recognized until deltoid is
A atrophied, long past the ideal time for repair. The widely held view that
deltoid is the abductor of the shoulder is erroneous. Deltoid provides
power and stamina, and abduction is initiated and maintained by the
suprascapular nerve, acting through supra and infraspinatus, their
tendons and attachments. Disruption of any component of this abduc
tor mechanism interferes with or precludes abduction. Wynn Parry
(1981) treated 145 patients in whom paralysis was confined to deltoid.
The range of abduction was full or nearly so, and a system of training
enabled most patients to return to full military duties. He wrote:
It must be stressed that these movements providing full abduction and
elevation are not trick movements, in the sense usually associated with
this word; all the muscles involved normally help to abduct the shoulder.
The scapulohumeral rhythm is quite normal and in the later stages of
re-education the patient does not even need to rotate the humerus


externally to initiate movement.
Seddon (1975) was a little more cautious, finding abduction to about
155° was more usual. The ISHA is diminished by about 20° in uncom
B plicated ruptures of the axillary nerve when there is no stiffness of the
shoulder.
Fig. 48.38 A left accessory palsy. Scapular winging, without prominence
Suprascapular nerve
of the lower fibres of trapezius, in a case where there is some early
recovery into the upper fibres after repair of the accessory nerve. A, At The suprascapular nerve is essential for abduction and lateral rotation
rest, the scapula is displaced downwards and away from the spine. at the glenohumeral joint. When the nerve or the rotator cuff is torn,
B, Arm abducted. (Courtesy of Rolfe Birch, all rights reserved, published or both are injured, the ISHA is so reduced that the patient is unable
in Birch R, Surgical Disorders of the Peripheral Nerve, 2nd ed, 2011. to move the arm away from the body. At rest, the head of the humerus
Springer-Verlag, London.) drops inferiorly and migrates proximally in attempted abduction (see
Fig. 48.41). In isolated cuff tears, the ISHA opens to about 30° or even
more. In isolated axillary palsy, the ISHA is sometimes normal, or, more
posture of the scapula (Fig. 48.38). It is fortunate that repair of the often, reduced by about 20° (Figs 48.42, 48.43).
nerve is usually successful, even when repair is performed as late as
axillary nerve
4 years after injury, with early relief of pain long before there is re
innervation of muscle (Camp and Birch 2011). The nerve appears to be The axillary nerve innervates deltoid. Although a good range of eleva
relatively immune to the harmful effects of delayed repair. tion is usually maintained by an intact abductor mechanism, strength
and stamina are greatly reduced. Early diagnosis of rupture of the axil
Long thoracic nerve (nerve to lary nerve can prove difficult; the nerve is deeply seated, which means


serratus anterior) that Tinel’s sign is rarely detectable. Active movement is restricted by
The long thoracic nerve is frequently injured during operations around pain and by the restraint of any sling. The loss of sensation varies and
the first rib, in the posterior triangle and in the axilla, and by misplaced there may not be complete anaesthesia. Patients with an intact supra
intercostal drains. It is particularly susceptible to involvement in neu scapular nerve and an intact rotator cuff are able to initiate abduction
ralgic amyotrophy. Serratus palsy is usual in preganglionic injury to C5, and many can fully elevate the arm, or nearly so. The power of forward
6 and 7. Pain and loss of function are usual and are only slightly less flexion and of abduction is reduced to, at most, 30–40% of normal,
than those seen after accessory nerve palsy. The signs are characteristic. whereas extension, with the shoulder at 90° of abduction, is 10% or
The active ISHA is, on average, 130°; this is the only nerve lesion in less. One useful test is to palpate the posterior third of deltoid with the
which the active ISHA actually exceeds the total range of active abduc fingers and ask the patient to move the elbow gently backwards. It
tion. The scapula is pulled upwards and towards the spine by the unop should be possible to detect activity in the muscle when the arm is
posed action of trapezius (Fig. 48.39). This action is increased by the supported in a sling or by the examiner’s arm.
weight of the limb, which contributes to the winging and is most
notable in protraction.


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A B
C D
Fig. 48.39 Scapular winging in long thoracic palsy. This is easily distinguishable from the winging provoked by accessory palsy by the position of the
scapula, which is drawn upwards and towards the spine by the unopposed action of trapezius, levator scapulae and the rhomboids.
A, Arms at rest. B, Hands pressed against the wall. C, Attempted abduction. D, Oblique view. (Courtesy of Rolfe Birch, all rights reserved, published in
Birch R, Surgical Disorders of the Peripheral Nerve, 2nd ed, 2011. Springer-Verlag, London.)


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A
B
Fig. 48.40 Initiation of abduction, with opening of the active inferior
scapulohumeral angle (ISHA), was the first sign of recovery into
supraspinatus after repair of the suprascapular nerve. The lesion of the
axillary nerve was irreparable. A, At rest. B, Attempted abduction.
(Courtesy of Rolfe Birch, all rights reserved, published in Birch R, Surgical
Disorders of the Peripheral Nerve, 2nd ed, 2011. Springer-Verlag,
London.)


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A
B C
Fig. 48.41 Rupture of the rotator cuff, with lesions of the suprascapular and axillary nerves from fracture/dislocation of the shoulder. A, The range of
elevation at the right shoulder in a 74-year-old man, in whom there was clear evidence of recovery for both of the nerves. B–C, This shipwright held on
to a cable to rescue a man from the River Thames. The weight of the man and the force of the current were such that he felt the muscles tearing in his
right shoulder; then he felt the head of the humerus pulling out from the socket and his arm went dead. Both nerves were recovering. (Courtesy of Rolfe
Birch, all rights reserved, published in Birch R, Surgical Disorders of the Peripheral Nerve, 2nd ed, 2011. Springer-Verlag, London.)


Shoulder girdle and arm
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A B
C D
Fig. 48.42 Movement of the scapula in a case of rupture of the right axillary nerve. D, The active inferior scapulohumeral angle (ISHA) on the side of the
injury is reduced by 20°, showing that 20° of the range of elevation is provided by extra movement at the thoracoscapular joint. (Courtesy of Rolfe Birch,
all rights reserved, published in Birch R, Surgical Disorders of the Peripheral Nerve, 2nd ed, 2011. Springer-Verlag, London.)


Shoulder girdle and arm
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A B
C D
Fig. 48.43 A–D, Elevation of the upper limb in full medial rotation by supraspinatus in the absence of deltoid in four cases of proven rupture of the
axillary nerve. Note the activity in the clavicular head of pectoralis major in C. (Courtesy of Rolfe Birch, all rights reserved, published in Birch R, Surgical
Disorders of the Peripheral Nerve, 2nd ed, 2011. Springer-Verlag, London.)


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Dorsal scapular nerve Fig. 48.35 The brachial
C4 plexus and its major
C5 Nerve to subclavius branches. The axillary
C5 Long thoracic nerve artery, shown in red
C6 outline, runs anterior to the
Suprascapular nerve radial nerve. The vertebral
C6
C7 levels are labelled C4–T2;
LATERAL CORD the spinal nerves are
C7 C8
POSTERIOR CORD labelled C5–T1 (white
T1 circles).
T1 Pectoralis minor
Musculocutaneous nerve
T2
Axillary nerve
Short head of biceps
Scalenus anterior Coracobrachialis
RADIAL NERVE
ULNAR NERVE
Medial pectoral nerve
MEDIAN NERVE
Lateral pectoral nerve
MEDIAL CORD
Subscapular nerves
to subscapularis
and teres major
Medial cutaneous nerve of forearm
Thoracodorsal nerve
Medial cutaneous nerve of arm
Latissimus dorsi
48.45). It pierces coracobrachialis a variable distance below the tip of Medial cutaneous nerve of the forearm
the coracoid process and then descends laterally between biceps brachii
and brachialis to the lateral side of the arm. The first branch, to coraco
The medial cutaneous nerve of the forearm comes from the medial cord
brachialis, may pass into the muscle no more than 2 cm distal to the
(T1) (see Fig. 48.34). It lies initially between the axillary artery and vein,
tip of the coracoid; fibres from C7 may branch directly from the lateral
and gives off a ramus that pierces the deep fascia to supply the skin over
cord. Branches to biceps brachii and brachialis leave after the musculo
the biceps, almost to the elbow. The nerve descends medial to the bra
cutaneous nerve has pierced coracobrachialis. There are usually two
chial artery, pierces the deep fascia with the basilic vein midway in the
branches to brachialis; the lower branch also supplies the anterior


arm, and divides into anterior and posterior branches. Its further course
aspect of the elbow joint. The nerve to biceps brachii is consistently
is described on page 860.
accompanied by a vascular pedicle. The nerve now inclines lateral and
deep, into the plane between brachialis posteriorly and biceps anteri
Median nerve
orly, where it supplies a small branch to the humerus that enters the
shaft with the nutrient artery. Below the branches to brachialis, the
The median nerve has two roots from the lateral (C5, 6, 7) and medial
musculocutaneous nerve continues as the lateral cutaneous nerve of the
(C8, T1) cords, which embrace the third part of the axillary artery and
forearm.
unite anterior or lateral to it (see Figs 48.29, 48.44, 46.7, 46.10). Some
The musculocutaneous nerve has frequent variations. It may run
fibres from C7 often leave the lateral root in the lower part of the axilla;
behind coracobrachialis or adhere for some distance to the median
they pass distomedially posterior to the medial root, and usually ante
nerve and pass behind biceps brachii. Some fibres of the median nerve
rior to the axillary artery, to join the ulnar nerve. Clinically, they are
may run in the musculocutaneous nerve, leaving it to join their proper
believed to be mainly motor and to supply flexor carpi ulnaris. If the
trunk; less frequently, the reverse occurs, and the median nerve sends a
lateral root is small, the musculocutaneous nerve (C5, 6, 7) connects
branch to the musculocutaneous nerve. Occasionally, it supplies prona
with the median nerve in the arm. It gives off vascular branches to the
tor teres and may replace radial branches to the dorsal surface of the
brachial artery. The further course of the median nerve is described on
thumb.
pages 858 and 891.
Medial cutaneous nerve of the arm
Ulnar nerve
The medial cutaneous nerve of the arm (C8, T1) is the smallest and
The ulnar nerve arises from the medial cord (C8, T1) but often receives


most medial branch of the brachial plexus, arising from the medial
fibres from the ventral ramus of C7. It usually has no branches in the
cord (see Fig. 48.35). It crosses the axilla, either anterior or posterior to
arm, but occasionally may give a branch to the medial head of triceps
the axillary vein, then passes medial to the axillary vein, communicates
(see Figs 48.29, 48.44, 46.12). The nerve runs distally through the
with the intercostobrachial nerve, and descends medial to the brachial
axilla, medial to the axillary artery and between it and the vein, and
artery and basilic vein. It pierces the deep fascia at the midpoint of the
continues distally medial to the brachial artery as far as the midarm.
upper arm to supply the skin over the medial aspect of the distal third
Here, it pierces the medial intermuscular septum, inclining medially as
of the upper arm (see Fig. 48.34). Sometimes, the medial cutaneous
it descends anterior to the medial head of triceps to the interval between
nerve of the arm and the intercostobrachial nerve are connected in a
the medial epicondyle and the olecranon. The further course of the
plexiform manner in the axilla. The intercostobrachial nerve may be
ulnar nerve is described on pages 859 and 893.
large and reinforced by part of the lateral cutaneous branch of the
third intercostal nerve. It then replaces the medial cutaneous nerve
Radial nerve
of the arm and receives a connection representing the latter from
the brachial plexus (occasionally, this connection is absent). It con
nects with the posterior branch of the medial cutaneous nerve of the The radial nerve is the largest branch of the brachial plexus. It arises
forearm. from the posterior cord (C5, 6, 7, 8, occasionally T1) (see Figs 48.33,


axilla
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Coracobrachialis The branches of the radial nerve in the upper arm are: muscular,
cutaneous, articular and superficial terminal and posterior interosseous.
Deltoid
Muscular branches
Axillary artery Muscular branches supply triceps, anconeus, brachioradialis, extensor
Biceps carpi radialis longus and brachialis in medial, posterior and lateral
brachii,
groups. Medial muscular branches arise from the radial nerve on the
Axillary nerve short
medial side of the arm. They supply the medial and long heads of
head
triceps. The branch to the medial head is a long, slender filament that
Pectoralis
Teres major major lies close to the ulnar nerve as far as the distal third of the arm, and is
often termed the ulnar collateral nerve. A large posterior muscular
branch arises from the nerve as it lies in the humeral groove. It divides
Coraco-
to supply the medial and lateral heads of triceps and anconeus. The
brachialis
branch to anconeus is a long nerve that descends in the medial head
Radial nerve of triceps and partially supplies it; the nerve is accompanied by the
Musculo-
middle collateral branch of the profunda brachii artery and passes
cutaneous
behind the elbow joint to end in anconeus. Lateral muscular branches
nerve
Median nerve arise in front of the lateral intermuscular septum and supply the lateral
part of brachialis, brachioradialis and extensor carpi radialis longus.
Cutaneous branches
Profunda
brachii Cutaneous branches are the posterior and lower lateral cutaneous
artery Biceps brachii nerves of the arm and the posterior cutaneous nerve of the forearm.
Posterior cutaneous nerve of the arm The small posterior cutaneous
Triceps brachii,
nerve of the arm arises in the axilla and passes medially to supply the
long head
skin on the dorsal surface of the arm nearly as far as the olecranon. It
crosses posterior to, and communicates with, the intercostobrachial
nerve.
Ulnar nerve
Superior ulnar Lower lateral cutaneous nerve of the arm The lower lateral cutaneous
collateral artery nerve of the arm perforates the lateral head of triceps distal to the


deltoid tuberosity, passes to the front of the elbow close to the cephalic
Triceps brachii,
Brachialis vein, and supplies the skin of the lateral part of the lower half of the
medial head
arm.
Posterior cutaneous nerve of the forearm The posterior cutaneous
nerve of the forearm arises with the lower lateral cutaneous nerve of the
arm. Perforating the lateral head of triceps, it descends first lateral in
Inferior ulnar the arm, then along the dorsum of the forearm to the wrist, supplying
Lateral cutaneous
collateral artery the skin in its course and joining, near its end, with dorsal branches of
nerve of forearm
the lateral cutaneous nerve of the forearm.
Brachial artery
Medial
Median nerve AXILLA
epicondyle
BOUNDARIES
Brachioradialis
The axilla is a pyramidal region between the upper thoracic wall and
Flexor muscles
of forearm the arm (Figs 48.45–48.46; see Fig. 48.35). Its blunt apex continues
into the root of the neck (cervicoaxillary canal) between the external
border of the first rib, superior border of the scapula, posterior surface
of the clavicle, and the medial aspect of the coracoid process. Its trian
gular base, which is virtual, can be imagined as facing downwards; it
Fig. 48.44 The left upper arm dissected to show the musculocutaneous is broad at the chest and narrow at the arm, and corresponds to the
nerve. Note also the changing relationship of the brachial artery and skin and a thick layer of axillary fascia between the inferior borders of
median nerve. Anterior aspect. (With permission from Waschke J, Paulsen
pectoralis major anteriorly and latissimus dorsi posteriorly. It is
F (eds), Sobotta Atlas of Human Anatomy, 15th ed, Elsevier, Urban &
convex upwards, conforming to the concavity of the armpit.
Fischer. Copyright 2013.)
The anterior wall is formed by pectorales major and minor, the
former covering the whole wall, and the latter its intermediate cranial
part, with a clear fascial plane between the two muscles. The interval


48.45, 46.9) and descends behind the third part of the axillary artery between the upper border of pectoralis minor and clavicle is occupied
and the upper part of the brachial artery, anterior to subscapularis above by the clavipectoral fascia. The posterior wall is formed by subscapularis
and the tendons of latissimus dorsi and teres major below, giving superiorly and teres major and latissimus dorsi inferiorly (Fig. 48.47).
branches to the medial head of triceps at this level (see Fig. 48.33). With The medial ‘wall’ is convex laterally and is composed of the first four
the profunda brachii artery, it inclines dorsally, passing through the ribs and their associated intercostal muscles, together with the upper
lower triangular space below the lower border of teres major, between part of serratus anterior. The anterior and posterior walls converge later
the long head of triceps and the humerus. Here, it supplies the long ally; the ‘wall’ is narrow and consists of the humeral intertubercular
head of triceps and gives rise to the posterior cutaneous nerve of the sulcus. The lateral angle lodges coracobrachialis and biceps.
arm, which supplies the skin along the posterior surface of the upper
arm. It then spirals obliquely across the back of the humerus, lying
posterior to the uppermost fibres of the medial head of triceps, which CONTENTS
separate the nerve from the bone in the first part of the spiral groove.
It gives off a muscular branch to the lateral head of triceps and a branch The axilla contains the axillary vessels, the infraclavicular part of the
that passes through the medial head of triceps to innervate anconeus. brachial plexus and its branches, lateral branches of some intercostal
On reaching the lateral side of the humerus, the radial nerve pierces nerves, many lymph nodes and vessels, loose adipose areolar tissue and,
the lateral intermuscular septum to enter the anterior compartment of in many instances, the ‘axillary tail’ of the breast. The axillary vessels
the arm. The further course of the radial nerve is described on pages and brachial plexus run from the apex to the base along the lateral wall,


860 and 894. nearer to the anterior wall; the axillary vein is anteromedial to the artery.


Shoulder girdle and arm
834
6
noiTCeS
Anterior cervical nodes, superficial and deep nodes Splenius cervicis
Scalenus medius Trapezius
External jugular vein
Levator scapulae Subclavian artery
Sternocleidomastoid
Lateral cervical nodes, Lateral supraclavicular nerve
Omohyoid, superior belly superficial nodes
Suprascapular Clavicle
Transverse cervical artery and vein
artery and vein, superficial
cervical branches
Suprascapular nerve
Anterior cervical nodes, Cephalic vein
superficial and deep nodes
Deltoid
Scalenus anterior
Suprascapular nodes
Sternohyoid (posterior axillary nodes)
Left jugular trunk Pectoralis major
Pectoralis minor
Inferior bulb of internal
jugular vein Radial nerve
Musculocutaneous nerve
Anterior jugular vein
Posterior circumflex
Jugular venous arch humeral artery
Sternoclavicular joint;
articular disc Brachial vein
Thoracic duct, cervical part Cephalic vein
External jugular vein
Lateral cervical node,
Ulnar nerve
inferior deep node
Left subclavian trunk and
Medial cutaneous
bronchomediastinal trunk
nerve of arm
Subclavius
Pectoralis major Serratus anterior
Pectoralis minor
Long thoracic nerve
Intercostal nodes
Infraclavicular nodes Lateral axillary nodes
Superior thoracic artery Branch from T3 to intercostobrachial nerve
Central axillary nodes Lateral thoracic artery and vein
Pectoral nodes Axillary vein
Fig. 48.45 The left axillary fossa and the deep aspect of the thoracic inlet, anterior aspect. The clavicle has been partially removed and the pectoral
muscles have been reflected. (With permission from Waschke J, Paulsen F (eds), Sobotta Atlas of Human Anatomy, 15th ed, Elsevier, Urban & Fischer.
Copyright 2013.)
The obliquity of the upper ribs means that the neurovascular bundle, partly to the central and apical axillary groups, and partly to the inferior
after it emerges from behind the clavicle, crosses the first intercostal deep cervical nodes. The anterior group of four or five nodes spreads


space; its relations are, therefore, different at upper and lower levels. along the inferior border of pectoralis minor near the lateral thoracic
Thoracic branches of the axillary artery are in contact with the pectoral vessels. Their afferents drain the skin and muscles of the supraumbilical
muscles; the lateral thoracic artery reaches the thoracic wall along the anterolateral body wall and breast, and efferents pass partly to the
lateral margin of pectoralis minor. Subscapular vessels descend on the central and partly to the apical axillary nodes. The posterior group of
posterior wall at the lower margin of subscapularis. The subscapular six or seven nodes lie on the inferior margin of the posterior axillary
and thoracodorsal nerves cross the anterior surface of latissimus dorsi wall, along the subscapular vessels. Their afferents drain the skin and
at different inclinations. Circumflex scapular vessels wind round the superficial muscles of the inferior posterior region of the neck and the
lateral border of the scapula; posterior circumflex humeral vessels and dorsal aspect of the trunk down to the iliac crest; efferents pass to the
the axillary nerve curve back and laterally around the surgical neck of apical and central axillary nodes. A central group of three or four large
the humerus (see Figs 48.47, 48.31). nodes embedded in axillary fat receives afferents from all preceding
No large vessel lies on the medial ‘wall’, which is crossed proximally groups, and their efferents drain to the apical nodes. An apical group
only by small branches of the superior thoracic artery. The long thoracic of six to twelve nodes is partly posterior to the superior part of pectoralis
nerve descends on serratus anterior and the intercostobrachial nerve minor and partly above its superior border, extending to the apex of
perforates the upper anterior part of this wall, crossing the axilla to its the axilla medial to the axillary vein. The only direct territorial afferents
lateral ‘wall’. are those that accompany the cephalic vein and/or some that drain the
upper peripheral region of the breast; the group drains all the other
axillary nodes. Their efferents unite as the subclavian trunk and drain


AXILLARY LYMPH NODES directly to either the jugulosubclavian venous junction, the subclavian
vein, the jugular lymphatic trunk or (occasionally) to a right lymphatic
There are between 20 and 30 axillary nodes, which may be divided into duct; the left trunk usually ends in the thoracic duct (see Fig. 29.16). A
five not wholly distinct groups, namely: lateral, anterior (pectoral), pos few efferents from apical nodes usually reach the inferior deep cervical
terior (subscapular), central and apical (see Fig. 53.24). Four of the nodes.
groups are intermediary; only the apical group is terminal. Collectively, One or two infraclavicular nodes appear beside the cephalic vein in
they drain the entire upper limb, breast and trunk above the umbilicus. the groove between pectoralis major and deltoid, just inferior to the
The lateral group of four to six nodes is posteromedial to the axillary clavicle. Their efferents pass through the clavipectoral fascia to the
vein; its afferents drain the whole limb, except the vessels that accom apical axillary nodes. Occasionally, some pass anterior to the clavicle to
pany the cephalic vein (Fig. 48.48, see Fig. 53.24). Efferent vessels pass the inferior deep cervical (supraclavicular) nodes.


axilla
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Pectoralis minor Coracobrachialis
Bonus e-book images
Pectoralis major Subcoracobrachial bursa
Biceps brachii, short head
Cephalic vein
Fig. 48.36 The active inferior scapulohumeral angle (ISHA) in a
Subscapularis bursa
normal shoulder is about 170°.
Biceps brachii,
long head tendon
Fig. 48.37 A right accessory palsy.
Greater tubercle
First rib
Fig. 48.38 A left accessory palsy.
Axillary vein
Fig. 48.39 Scapular winging in long thoracic palsy.
Axillary artery
Fig. 48.40 Initiation of abduction, with opening of the active inferior
Brachial plexus scapulohumeral angle (ISHA), was the first sign of recovery into
supraspinatus after repair of the suprascapular nerve.
Long thoracic nerve
Serratus anterior Fig. 48.41 Rupture of the rotator cuff, with lesions of the
suprascapular and axillary nerves from fracture/dislocation of the
Subscapularis shoulder.
Fig. 48.42 Movement of the scapula in a case of rupture of the
right axillary nerve.
Fig. 48.43 Elevation of the upper limb in full medial rotation by
supraspinatus in the absence of deltoid in four cases of proven
rupture of the axillary nerve.
Subdeltoid bursa
Branches of Head of humerus
suprascapular
Glenoid fossa
Scapula Infraspinatus vessels and nerve
to infraspinatus Deltoid
Intratendinous bursa
Fig. 48.46 A transverse section through the left shoulder joint and axilla,
viewed from below. Compare with Figure 48.23A.
Transverse cervical artery Fig. 48.47 The left axillary artery and its branches.
Thyrocervical trunk Suprascapular artery (With permission from Drake RL, Vogl AW, Mitchell
Vertebral artery Deep branch of transverse cervical artery A (eds), Gray’s Anatomy for Students, 2nd ed,
Elsevier, Churchill Livingstone. Copyright 2010.)
Superficial cervical artery


Pectoralis minor
Superior thoracic artery
Subclavius
Thoraco-acromial artery
Subscapularis
Subscapular artery
Anterior circumflex
humeral artery
Posterior circumflex humeral artery
(quadrangular space)
Latissimus dorsi
Circumflex scapular artery
(upper triangular space)
Teres major
Profunda brachii artery
(lower triangular space)
Thoracodorsal artery
Lateral thoracic artery
Triceps brachii,
long head


Shoulder girdle and arm
836
6
noiTCeS
Scalenus anterior Fig. 48.48 The lymph nodes and vessels
associated with the left axilla. Arrows indicate the
Left subclavian trunk Apical nodes direction of flow. (With permission from Drake RL,
Thoracic duct Infraclavicular nodes Vogl AW, Mitchell A (eds), Gray’s Anatomy for
Superficial structures of upper limb Students, 2nd ed, Elsevier, Churchill Livingstone.
Copyright 2010.)
Central nodes
Pectoral nodes
Superior part of
mammary gland
Humeral nodes
Subscapular nodes
Deep structures
of upper limb
Anterolateral body wall
and centrolateral part
of mammary gland
KEY REFERENCES
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myogr Kinesiol 21:478–82. explanation for the clinical syndromes of rotator cuff failure.
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Bankart AS 1923 Recurrent or habitual dislocation of the shoulderjoint. A description of an example of the value of testing muscle capacity by
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The original description of the lesion that consumes so much clinical time. (that is, decrement from normal without testing against the power of the
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Birch R 2011 Surgical Disorders of the Peripheral Nerves, 2nd ed. London:
SpringerVerlag. Leijnse JNAL, Han SH, Kwon YH 2008 Morphology of deltoid origin and


An account of the current state-of-the-art practice of diagnosis and end tendons – a generic model. J Anat 213:733–42.
management of surgical lesions of the peripheral nerves, including the A description of the internal architecture of deltoid in relation to the discrete
brachial plexus. functions of the parts of that muscle.
Boileau P, Walch G 1997 The threedimensional geometry of the proximal Streit JJ, Lenarz CJ, Shishani Y et al 2012 Pectoralis major tendon transfer
humerus. Implications for surgical technique and prosthetic design. for the treatment of scapular winging due to long thoracic nerve palsy.
J Bone Joint Surg Br 79:857–65. J Shoulder Elbow Surg 21:685–90.
The seminal European publication that introduced the science of The largest series of the direct or indirect transfer of the sternal head of
measurement to the understanding of the morphology of the proximal pectoralis major for insufficiency of serratus anterior in symptomatic
humerus, and from which all subsequent work takes its lead. scapular dyskinesia.
Burkhart SS, Esch JC, Jolson RS 1993 The rotator crescent and rotator cable: Taylor GI, Razaboni RM (eds) 1994 Michel Salmon: Anatomic Studies. Book
an anatomic description of the shoulder’s ‘suspension bridge’. Arthros 1, Arteries of the Muscles of the Extremities and the Trunk. Book 2,
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A description and explanation of the clinical relevance of the anteroposterior Medical Publishing.
capsular thickening linking subscapularis with the posterior rotator cuff, A book that contains the translated work of Dr Michel Salmon: it describes
forming part of the fibrous ‘endoskeleton’ or fibrous frame (Gagey et al the blood supply to muscle, as well as the anastomotic pathways in the
1993) of the shoulder that confers stability on the moving humeral head. limbs.
Dancker M 2013 The clinicalfunctional anatomy of the teres major muscle Vangsness CT Jr, Jorgenson SS, Watson T et al 1994 The origin of the long


[diploma thesis]. Innsbruck Medical University. head of the biceps from the scapula and glenoid labrum. An anatomical
Teres major was little studied until this cadaveric study. The muscle might study of 100 shoulders. J Bone Joint Surg Br 76:951–4.
provide a motor for an absent or insufficient subscapularis; the information A detailed description of the variation in the cadaveric anatomy of the
given will assist the surgeon in planning transfer of the muscle. origin of biceps brachii, permitting more accurate interpretation of the
clinical variance of this structure.
Gagey O, Arcache J, Welby F et al 1993 [Fibrous frame of the rotator cuff.
The concept of fibrous lock]. [Article in French] Rev Chir Orthop Repara
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836.e1
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Atasoy E 2004 Thoracic outlet syndrome: anatomy. Hand Clin 20:7–14. A description of an example of the value of testing muscle capacity by
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Bankart AS 1923 Recurrent or habitual dislocation of the shoulderjoint.
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Br Med J 2:1132–3.
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The original description of the lesion that consumes so much clinical time.
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Dancker M 2013 The clinicalfunctional anatomy of the teres major muscle
scapular dyskinesia.
[diploma thesis]. Innsbruck Medical University.
Teres major was little studied until this cadaveric study. The muscle might Taylor GI, Razaboni RM (eds) 1994 Michel Salmon: Anatomic Studies. Book
provide a motor for an absent or insufficient subscapularis; the information 1, Arteries of the Muscles of the Extremities and the Trunk. Book 2,


given will assist the surgeon in planning transfer of the muscle. Arterial anastomotic pathways of the extremities. St Louis: Quality
Medical Publishing.
Dhir R, Lambert S 2014 The undescended scapular syndrome: Sprengel and
A book that contains the translated work of Dr Michel Salmon: it describes
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the blood supply to muscle, as well as the anastomotic pathways in the
Di Giacomo G, Pouliart N, Costantini A et al 2008 Atlas of Functional limbs.
Shoulder Anatomy. New York: Springer.
Vangsness CT Jr, Jorgenson SS, Watson T et al 1994 The origin of the long
Gagey O, Arcache J, Welby F et al 1993 [Fibrous frame of the rotator cuff.
head of the biceps from the scapula and glenoid labrum. An anatomical
The concept of fibrous lock]. [Article in French] Rev Chir Orthop Repara
study of 100 shoulders. J Bone Joint Surg Br 76:951–4.
trice Appar Mot 79:452–5.
A detailed description of the variation in the cadaveric anatomy of the
The seminal anatomical publication that describes the architecture of the
origin of biceps brachii, permitting more accurate interpretation of the
collagenous frame of the shoulder, and which also provides a cohesive
clinical variance of this structure.
explanation for the clinical syndromes of rotator cuff failure.
Gerber C, Schneeberger AG, Vinh TS 1990 The arterial vascularization of
the humeral head. An anatomical study. J Bone Joint Surg Am 72:
1486–94.


CHAPTER
49
Elbow and forearm
Fig. 49.1 Sensory
SKIN AND SOFT TISSUES
loss or disturbance
after complete
SKIN section of the medial
and lateral
Cutaneous vascular supply cutaneous nerves of
the forearm.
The skin of the elbow and forearm receives its blood supply from
muscle perforators, fasciocutaneous networks and direct cutaneous
vessels. The skin of the anterolateral cubital fossa is supplied by muscle
perforators arising from the radial collateral and radial recurrent arter-
ies. The skin of the medial cubital fossa receives branches from an
anastomosis between the inferior ulnar collateral and the ulnar recur-
rent arteries. Small direct cutaneous vessels spring from the brachial
artery. The skin of the posterolateral aspect of the elbow is supplied by Medial cutaneous nerve
Lateral cutaneous nerve
branches of the posterior interosseous recurrent artery and a rich plexus of forearm of forearm
of collateral and anastomosing arteries. The skin of the posteromedial
aspect is supplied by branches of the superior and inferior ulnar col-
lateral arteries and the posterior ulnar recurrent artery feeding into the
plexus.
The skin of the anterior forearm is supplied by fasciocutaneous
perforators; the largest is the inferior cubital artery, which arises from
the radial artery at the distal apex of the cubital fossa and extends to
midway down the forearm. Fasciocutaneous perforators from the radial
artery supply the lateral two-thirds of the anterior surface of the forearm
(see Fig. 46.5). The vessels pass in the intermuscular septa between the medial and lateral humeral epicondyles and augmented by the
brachioradialis and flexor carpi radialis, and between flexor carpi radi- bicipital aponeurosis, which sweeps across the medial and inferior part
alis and flexor digitorum superficialis. Fasciocutaneous perforators from of the fossa to the fascia over the superficial flexor muscles. Supinator
the ulnar artery supply skin over the ulnar side of the anterior forearm and brachialis lie in the floor of the fossa. From medial to lateral, the


and the medial quarter of the posterior forearm from the cubital fossa basilic, median cubital and cephalic veins lie in the superficial fascia.
to the wrist. A small contribution comes from musculocutaneous per- Branches of the medial cutaneous nerve of the forearm are closely
forators that pass through brachioradialis and flexor carpi ulnaris. related to the basilic vein. The lateral cutaneous nerve of the forearm
The skin of the distal third of the lateral forearm is supplied by the runs down alongside the lateral edge of the tendon of biceps brachii.
terminal perforating branches of the anterior interosseous artery. The Deep to the deep fascia, and passing from medial to lateral, are the
central half of the posterior surface of the forearm, from the lateral edge median nerve and the brachial artery, the latter inclining from the
of extensor digitorum, just below the lateral epicondyle of the humerus, medial side of the arm to pass down the fossa close to the midline.
to the wrist, is supplied by fasciocutaneous perforators from the pos- The radial and ulnar arteries, with their accompanying veins, originate
terior interosseous artery that pass along the intermuscular fascia in the lower part of the fossa. The radial nerve enters the fossa laterally
between extensor carpi ulnaris and extensor digiti minimi. in the groove between brachioradialis and brachialis, and divides into
the superficial radial and posterior interosseous nerves above the
Cutaneous innervation humero-radial joint. The superficial radial nerve continues down the
forearm under cover of brachioradialis.
A small area of skin anterolateral to the elbow is supplied by the lateral
cutaneous nerve of the arm. The skin overlying the posterior aspect of Compartments of the forearm
the elbow is innervated by the posterior cutaneous nerve of the arm and
proximal branches of the posterior cutaneous nerve of the forearm. The The deep fascia, the interosseous membrane and the fibrous intermus-
lateral cutaneous nerve of the forearm innervates the skin of the anterior cular septa, some of which pass between the deep fascia and bone,
half and radial posterior quarter of the forearm. The medial cutaneous divide the forearm into compartments. These include the superficial


nerve of the forearm supplies the skin overlying most of the elbow, the and deep flexor (anterior) compartments, the extensor (posterior) com-
ulnar half of the anterior forearm and the ulnar quarter of the posterior partment, and a proximolateral compartment that includes brachio-
forearm (Fig. 49.1 and p. 860). radialis and extensors carpi radialis longus and brevis (the mobile wad)
(Fig. 49.2). The dense sheath of the antebrachial fascia (the deep fascia
of the forearm) is continuous above with the brachial fascia. It is
SOFT TISSUES
attached to the olecranon, the posterior border of the ulna, and the
lateral and medial epicondyles. The fascia is thicker posteriorly and in
Cubital fossa
the lower forearm. It is strengthened above by tendinous fibres from
biceps and triceps. Near the wrist, two localized thickenings, the flexor
The cubital fossa is a triangular depression in the anterior aspect of the and extensor retinacula, retain the digital tendons in position (Ch. 50).
upper forearm (see Fig. 46.29). It is bounded proximally by the epi- From its deep surface, septa pass between muscles, providing areas of
condylar line, medially by the lateral margin of pronator teres, and additional attachment. Muscles arise from its inner aspect in the upper
laterally by the medial face of brachioradialis; it is bisected by the forearm. Vessels and nerves pass through apertures in the fascia; a large
tendon of biceps brachii. The deep fascia of the forearm forms its roof. aperture anterior to the elbow transmits a venous communication
It is continuous with the deep fascia of the anterior arm, attached to between superficial and deep veins. 837


Elbow and forEarm
838
6
noITCES
Trochlea
BONES
The trochlea is a pulley-shaped surface that covers the anterior, inferior
and posterior surfaces of the condyle of the humerus medially and
HUMERUS
articulates with the trochlear notch of the ulna. On its lateral side, it is
separated from the capitulum by a faint groove; its medial margin
Distal end of humerus
projects distally beyond the rest of the bone. When the elbow is
The distal end of the humerus is a modified condyle; it is wider trans- extended, the inferior and posterior aspects of the trochlea are in contact
versely and has articular and non-articular parts (Figs 49.3–49.4). The with the ulna but, as the joint is flexed, the trochlear notch slides on
articular part is curved forwards, so that its anterior and posterior sur- to the anterior aspect so that its posterior aspect is then left uncovered.
faces lie in front of the corresponding surfaces of the shaft. It articulates The downward projection of the medial edge of the trochlea is the
with the radius and the ulna at the elbow joint, and is divided by a faint principal factor in determining the degree of angulation between the
groove into a lateral capitulum and a medial trochlea. long axis of the humerus and the long axis of the supinated forearm
The capitulum is a rounded, convex projection, considerably less when the elbow is extended.
than half a sphere, which covers the anterior and inferior surfaces of
Medial epicondyle
the lateral part of the condyle of the humerus but does not extend on
to its posterior surface. It articulates with the discoid head of the radius, The medial border of the humerus ends by turning slightly backwards
which lies in contact with its inferior surface in full extension of the as the medial epicondyle, which forms a conspicuous, blunt projection
elbow but slides on to its anterior surface during flexion. The groove of on the medial side of the condyle. It is subcutaneous and usually visible,
the trochlea winds backwards and laterally from the anterior to the especially in passive flexion of the elbow. Its posterior surface is smooth


posterior surface of the bone, and is wider, deeper and more symmetri- and is crossed by the ulnar nerve, which lies in a shallow sulcus as it
cal posteriorly. Anteriorly, the medial flange of the pulley is longer than enters the forearm. The nerve can be felt and rolled against the bone
the lateral, and the surface adjoining its projecting medial margin is here; if jarred against the epicondyle, a characteristic tingling sensation
convex to accommodate itself to the medial part of the upper surface results. The lower part of the anterior surface of the medial epicondyle
of the coronoid process of the ulna. These asymmetries entail varying is marked by the attachment of the superficial group of forearm flexors.
angulation between the humeral and ulnar axes, together with some They arise from the epiphysis for the epicondyle but are entirely
conjunct rotation. The non-articular part of the condyle includes the extracapsular.
medial and lateral epicondyles, and the olecranon, coronoid and radial
Lateral epicondyle
fossae.
The lateral border of the humerus ends at the lateral epicondyle; its
lower portion constitutes the lateral supracondylar ridge. The lateral
epicondyle occupies the lateral part of the non-articular portion of the
condyle but does not project beyond the lateral supracondylar ridge. It
Anterior interosseous
artery and nerve
Extensor carpi Extensor digiti minimi 1 2
ulnaris and extensor digitorum
Posterior interosseous
artery and nerve
Extensor carpi
Ulna
radialis tendon
Flexor digitorum
profundus
Radius
Basilic vein
Ulnar artery Radial artery
and nerve
and superficial
Flexor carpi ulnaris
radial nerve
Palmaris longus Cephalic vein
Median nerve
Flexor carpi
Flexor digitorum radialis
superficialis
3 4 5
Fig. 49.4 The inferior aspect of the distal end of the left humerus. Key:


Fig. 49.2 Compartments of the forearm. A cross-section through the 1, trochlea; 2, capitulum; 3, medial epicondyle; 4, sulcus for ulnar nerve;
upper third of the left forearm. 5, lateral epicondyle.
1 Fig. 49.3 A, The anterior aspect of the distal end
of the left humerus. Key: 1, shaft; 2, medial
supracondylar ridge; 3, coronoid fossa; 4, medial
epicondyle; 5, trochlea; 6, lateral supracondylar
ridge; 7, radial fossa; 8, lateral epicondyle; 9,
capitulum. B, The posterior aspect of the distal
end of the left humerus. Key: 1, lateral
6
supracondylar ridge; 2, lateral epicondyle; 3,
2 medial supracondylar ridge; 4, medial epicondyle;
1 5, olecranon fossa; 6, sulcus for ulnar nerve; 7,
3 trochlea.
7
3
4
8
4 2
9 5
5 6
A B
7


bones
839
94
rETPaHC
turns slightly forwards, unlike the medial epicondyle, which turns Fig. 49.5 The articulated
slightly backwards. Its lateral and anterior surfaces show a well-marked radius and ulna: anterior
impression for the superficial group of the extensor muscles of the view, showing muscle
forearm (see Fig. 48.11A), which arise from the lateral side of the lower attachments. Note that the
humeral epiphysis; like the flexors, they are extracapsular. The posterior 1 hatched lines denote
surface, which is very slightly convex, is easily felt in a depression visible extension of muscular
behind the extended elbow. A small area on the posterior surface gives attachments on to the
interosseous membrane.
origin to anconeus.
Key: 1, flexor digitorum
2
Olecranon, coronoid and radial fossae superficialis; 2, pronator
teres (ulnar head); 3,
The olecranon fossa is a deep hollow on the posterior surface of 3
brachialis; 4, supinator; 5,
the condyle, immediately above the trochlea, that lodges the tip of the 6
flexor digitorum profundus;
olecranon of the ulna when the elbow is extended. The floor of the
6, biceps; 7, supinator; 8,
fossa is always thin and may be partially deficient. A similar but smaller 4
7 flexor digitorum superficialis
hollow, the coronoid fossa, lies immediately above the trochlea on the
(oblique line); 9, pronator
anterior surface of the condyle and accommodates the anterior margin
teres; 10, flexor pollicis
of the coronoid process of the ulna during flexion of the elbow. A very
longus; 11, pronator
slight depression, the radial fossa, lies above the capitulum on the quadratus; 12,
lateral side of the coronoid fossa and is related to the margin of the 8 brachioradialis.
head of the radius in full flexion of the elbow.
Ossification
The distal humerus ossifies as follows. During the first year, ossification
5


begins in the capitulum and extends medially to form the main part of
the articular surface. The centre for the medial part of the trochlea 9
appears in the ninth year in females and tenth year in males. Ossifica-
tion begins in the medial epicondyle in the fourth year in females and
the sixth in males, and in the lateral epicondyle in about the twelfth
10
year. The centre for the medial epicondyle forms a separate epiphysis,
which is entirely extracapsular, on the posteromedial aspect of the
epicondyle. It is separated from the rest of the lower epiphysis by a
downgrowth from the shaft, with which it unites at about the twentieth
year. The centres for the lateral epicondyle, capitulum and trochlea fuse
around puberty, and the composite epiphysis unites with the shaft in
the fourteenth year in females and sixteenth in males.
RADIUS
The radius is the lateral bone of the forearm (Figs 49.5–49.7). It has
11
expanded proximal and distal ends; the distal is much the broader. The
shaft widens rapidly towards its distal end, and is convex laterally and
concave anteriorly in its distal part. The radius articulates with the
humeral capitulum, the ulna and the carpus.
12
Proximal radius
The proximal radius includes a head, neck and tuberosity. The head is
discoid, its proximal surface a shallow cup for articulation with the
humeral capitulum. Its smooth articular periphery is vertically deepest
medially, where it contacts the ulnar radial notch. The posterior surface
of the radial head is palpable on the posterolateral aspect of the
proximal to the thenar eminence. The medial surface is the ulnar notch,
extended elbow. The head overhangs the neck, which is the circumfer-
which is smooth and anteroposteriorly concave for articulation with the
ential constriction immediately below it, particularly laterally. The
head of the ulna. The posterior surface has a palpable dorsal tubercle
tuberosity is distal to the medial part of the neck; posteriorly, it is rough,
(Lister’s tubercle), limited medially by an oblique groove and in line


whereas anteriorly, it is usually smooth.
with the cleft between the index and middle fingers. Lateral to the
Radial shaft tubercle is a wide, shallow groove, divided by a vertical ridge.
The radial shaft has a lateral convexity and is triangular in cross-section. Muscular, ligamentous and
The interosseous border is sharp, except proximally, near the tuberosity,
articular attachments
and distally, where the interosseous border is the posterior margin of a
small, elongated, triangular area, proximal to the ulnar notch. These The proximal articular surface of the radial head and its circumference
two areas form the medial surface of the radial shaft. The interosseous are covered by hyaline cartilage. The upper rim fits the groove between
membrane is attached to the distal three-quarters of the radial shaft, the capitulum and trochlea and enters the radial fossa in flexion. The
and connects the radius to the ulna. The anterior surface, between articular circumference articulates with the ulnar radial notch and
anterior and interosseous borders, is concave transversely and shows a anular ligament, within which it rotates in pronation and supination.
distal anterior curvature. There is a proximally directed nutrient foramen The radial neck is enclosed by the narrower distal part of the ligament,
and canal near the midpoint of the shaft. The posterior surface of the from which it is separated by a synovial protrusion from the superior
shaft, between the interosseous and posterior borders, is largely flat but radio-ulnar joint. The posterior area of the tuberosity is marked by the
may be slightly hollow proximally. The lateral surface is gently convex. tendon of biceps brachii, which is separated from a smooth anterior
A finely irregular oval area occurs near the midshaft; further distally, the area by a bursa. The oblique cord is attached just distal to the bursa.
surface is smooth. Flexor digitorum superficialis is attached to the proximal anterior
surface of the radius by a thin, wide head. Flexor pollicis longus has an
Distal radius extensive attachment to the proximal two-thirds of the anterior surface
The distal end of the radius (Fig. 49.8) is the widest part and is four- of the radial shaft, overlying the nutrient foramen. Pronator quadratus


sided in section. The lateral surface is slightly rough, projecting distally is attached to the distal quarter of the anterior radial shaft; a small,
as the radial styloid process. The smooth carpal articular surface is triangular area proximal to the ulnar notch gives attachment to the
divided by a ridge into medial and lateral areas. The medial distal radial deepest part of the muscle. Pronator teres is attached to a rough area
articular surface is quadrangular, whereas the lateral part of the articular near the midpoint of the lateral surface of the radial shaft, at its maximal
surface is triangular and curves on to the styloid process. The anterior curvature. Proximally, supinator is attached to a long, V-shaped area on
surface of the distal radius is a thick, palpable, prominent ridge 2 cm the lateral surface of the shaft. Distal to pronator teres, the lateral


Elbow and forEarm
840
6
noITCES
Fig. 49.6 The articulated 1 2 3 4
1 radius and ulna: posterior
view, showing muscle
7 attachments. Key: 1, triceps;
2, biceps; 3, supinator; 4,
abductor pollicis longus; 5,
pronator teres; 6, extensor
pollicis brevis; 7,
8
subcutaneous area; 8,
anconeus; 9, posterior
border: attachment for
common aponeurosis of
2
extensor carpi ulnaris, flexor
carpi ulnaris, flexor digitorum
profundus; 10, extensor
3
9 pollicis longus; 11, extensor
indicis.
5 6 7 8 9
Fig. 49.8 The distal end of the left radius and ulna. Key: 1, styloid
4 process of radius; 2, dorsal tubercle; 3, groove for tendon of extensor
carpi ulnaris; 4, styloid process of ulna; 5, facet for scaphoid; 6, facet for
lunate; 7, inferior radio-ulnar articulation; 8, area of contact with articular
disc; 9, area for attachment of articular disc. Compare with Fig. 50.18A.
5
10
surface is covered by tendons of brachioradialis, extensor carpi radialis
longus and brevis. On the posterior surface, abductor pollicis longus is
attached proximally, and extensor pollicis brevis more distally. The
6 remaining surface is devoid of attachments and covered by the long and
short extensors of the thumb. The lateral surface, proximal to the styloid
process, receives the attachment of brachioradialis and is crossed
11
obliquely, downwards and forwards, by the tendons of abductor pollicis
longus and extensor pollicis brevis. The radial styloid process projects
beyond that of the ulna, its apex covered by the tendons of abductor
pollicis longus and extensor pollicis brevis. The lateral radiocarpal liga-


ment is attached to its tip, and the palmar radiocarpal ligament is
attached to the terminal ridge on the anterior surface of the lower end.
The base of the triangular articular disc of the inferior radio-ulnar joint
is attached to a smooth ridge distal to the ulnar notch. A narrow protru-
sion of synovial membrane extends proximally from the ulnar notch,
anterior to the lower end of the interosseous membrane. The lateral part
of the carpal articular surface articulates with the scaphoid, and the
medial part with the lateral part of the lunate. In full adduction, the
proximal surface of the lunate is wholly in contact with the radius.
The radial dorsal tubercle receives a slip from the extensor retinacu-
lum and is grooved medially by the tendon of extensor pollicis longus.
The wide groove lateral to the tubercle contains the tendons of extensor
carpi radialis longus laterally and extensor carpi radialis brevis medially,
together with their synovial sheaths. Medially, the dorsal surface is
grooved by the tendons of extensor digitorum, separated from the bone
Fig. 49.7 The proximal end of the by the tendons of extensor indicis and the posterior interosseous nerve.
left radius: anterior view. Key: 1, The dorsal radiocarpal ligament is attached to the distal margin of this
1 head; 2, radial tuberosity; 3, shaft; surface.
4, neck.
Vascular supply
The radius is supplied by branches of the radial, ulnar, and anterior and
4
posterior interosseous arteries through multiple metaphysial nutrient
foramina. Usually, there is one nutrient diaphysial foramen located on
the anterior surface of the bone, which is directed proximally towards
the elbow. A network of small fascioperiosteal and musculoperiosteal
vessels arise from the compartmental vessels and reach the bone via its
2 septal and muscular attachments.
The dorsal metaphysis of the distal radius is richly supplied (Fig.
49.9A). Branches connect the anterior interosseous artery proximally to
the dorsal carpal arch distally. These pass through the fourth and fifth
extensor compartments of the wrist and provide metaphysial nutrient


arteries. Intercompartmental vessels send nutrient arteries to the radius
through the retinaculum between the first and second dorsal compart-
ments, and the second and third dorsal compartments. These vessels
originate from the radial artery and anterior interosseous arteries,
respectively, and anastomose with the dorsal carpal arch.
Ossification
The radius ossifies from three centres. One appears centrally in the shaft
in the eighth week of fetal life, and the others appear in each end (see
3 Figs 48.13, 49.12). Ossification begins in the distal epiphysis towards
the end of the first postnatal year and in the proximal epiphysis during
the fourth year in females and the fifth year in males. The proximal


bones
841
94
rETPaHC
A
B
Fourth extensor
compartment Superficial palmar arch
Dorsal intercarpal arch
branch of fifth
Deep palmar arch
extensor Dorsal radiocarpal arch
compartment artery Branch of ulnar artery contributing
Second extensor to dorsal intercarpal arch
Fifth extensor compartment branch of
compartment artery 1,2 intercompartmental
Palmar intercarpal arch
Ulnar artery supraretinacular artery
Dorsal supra- 1,2 intercompartmental
retinacular arch supraretinacular artery
Radial artery
Fourth extensor Radial half of
compartment artery Second extensor palmar carpal arch Ulnar half of
compartment branch palmar carpal arch
Oblique dorsal artery of 2,3 inter- Palmar metaphysial
of distal ulna compartmental arch Pronator quadratus
supraretinacular
Posterior division artery
of anterior 2,3 intercompartmental Ulnar artery
interosseous artery Radial artery
supraretinacular artery
Anterior division of
anterior interosseous artery
Posterior
interosseous artery Anterior interosseous
Anterior division of artery
Anterior anterior interosseous
interosseous artery artery
Fig. 49.9 A–B, The extraosseous arterial supply to the distal radius and ulna and
C
the carpus. A, Dorsal aspect; B, Palmar aspect; C Lateral aspect viewed from the
radial side.
Branch to lateral trapezium and
thumb metacarpal
Dorsal intercarpal arch
Branch to scaphoid tubercle and trapezium
Artery to dorsal ridge of scaphoid
Superficial palmar artery
Palmar radiocarpal arch
Dorsal radiocarpal arch
Radial artery
epiphysis fuses in the fourteenth year in females and seventeenth in proximal area of the trochlear notch. Its base is slightly constricted
males, and the distal in the seventeenth and nineteenth years, respec- where it joins the shaft and is the narrowest part of the proximal ulna.


tively. A fourth centre sometimes appears in the tuberosity at about the The coronoid process projects anteriorly distal to the olecranon. Its
fourteenth or fifteenth year. proximal aspect forms the distal part of the trochlear notch. On the
lateral surface, distal to the trochlear notch, a shallow, smooth, oval
radial notch articulates with the radial head. Distal to the radial notch,
ULNA the surface is hollow to accommodate the radial tuberosity during
pronation and supination. The anterior surface of the coronoid is tri-
The ulna is medial to the radius in the supinated forearm. Its proximal angular. Its distal part is the tuberosity of the ulna and its medial border
end is a massive hook, concave forwards, that articulates with the distal is sharp and bears a small tubercle proximally.
humerus (Figs 49.10–49.11). The lateral border of the shaft is a sharp The trochlear notch articulates with the trochlea of the humerus. It
interosseous crest. The bone diminishes progressively from its proximal is constricted at the junction of the olecranon and coronoid processes,
mass throughout almost its whole length, but, at its distal end, expands where their articular surfaces may be separated by a narrow, rough,
into a small, rounded head and styloid process. The shaft is triangular non-articular strip. A smooth ridge, adapted to the groove on the
in cross-section proximally, and almost cylindrical distally. Along humeral trochlea, divides the notch into medial and lateral parts. The
its whole length, the ulna is slightly convex posteriorly. Mediolaterally, medial fits into the trochlear flange. The radial notch, an oval or oblong
its profile is sinuous; the proximal half has a slight curvature that proximal depression on the lateral aspect of the coronoid process,
is concave laterally and the distal half a curvature that is concave articulates with the periphery of the radial head and is separated from
medially. the trochlear notch by a smooth ridge.
Proximal ulna Ulnar shaft
The proximal end of the ulna has large olecranon and coronoid pro- The ulnar shaft is triangular in cross-section in its proximal three-


cesses, and trochlear and radial notches that articulate with the humerus quarters, but distally is almost cylindrical (see Figs 49.31–49.32). It has
and radius, respectively. The olecranon is more proximal and is bent anterior, posterior and medial surfaces and interosseous, posterior and
forwards at its summit like a beak that enters the olecr anon fossa of the anterior borders. The interosseous border is a conspicuous lateral crest
humerus in extension. Its posterior surface is smooth, triangular and in its middle half. Proximally, it becomes the supinator crest, which is
subcutaneous, and its proximal border underlies the ‘point’ of the continuous with the posterior border of a depression distal to the radial
elbow. In extension, it can be felt near a line joining the humeral epi- notch. Distally, it disappears. The rounded anterior border starts medial
condyles, but in flexion, it descends, so that the three osseous points to the ulnar tuberosity, descends backwards, and is usually traceable to
form an isosceles triangle. Its anterior, articular surface forms the the base of the styloid process. The posterior border, also rounded,


Elbow and forEarm
842
6
noITCES
descends from the apex of the posterior aspect of the olecranon, and
Olecranon curves laterally to reach the styloid process. It is palpable throughout
its length in a longitudinal furrow, most obvious when the elbow is
Trochlear notch
fully flexed.
The anterior surface, between the interosseous and anterior borders,
Coronoid process is longitudinally grooved, sometimes deeply (see Fig. 49.10). Proximal
to its midpoint, a proximally directed nutrient foramen admits a branch
Anular ligament
Cut proximal edge of anterior of the anterior interosseous artery. Distally, it is crossed obliquely by a
interosseous nerve just distal rough, variable prominence, descending from the interosseous to the
to its origin anterior border. The medial surface, between the anterior and posterior
Tuberosity of radius borders, is transversely convex and smooth. The posterior surface,
between the posterior and interosseous borders, is divided into three
Common interosseous artery
areas. The most proximal is limited by a sometimes faint, oblique line
that ascends laterally from the junction of the middle and upper thirds
Anterior interosseous artery Posterior interosseous of the posterior border to the posterior end of the radial notch. The
artery region distal to this line is divided into a larger medial and narrower
Nutrient artery to ulna Anterior oblique line lateral strip by a vertical ridge, which is usually distinct only in its
Oblique cord proximal three-quarters.
Anterior interosseous nerve
Distal ulna
Posterior border Nutrient artery The distal end of the ulna is slightly expanded and has a head and
to radius styloid process. The head is palpable and visible in pronation on the
Medial surface
posteromedial aspect of the wrist. Its lateral convex articular surface fits
the radial ulnar notch. Its smooth distal surface is separated from the
carpus by an articular disc, the apex of which is attached to a rough area
Anterior border Anterior surface between the articular surface and styloid process. The ulnar styloid
Anterior surface Anterior border process is a short, round, posterolateral projection of the distal end of
Interosseous border the ulna, palpable in supination about 1 cm proximal to the plane of


the radial styloid. A posterior vertical groove is present between the
Interosseous membrane
Interosseous border head and styloid process.
Muscular branches
Muscular, ligamentous and
articular attachments
The capsule of the elbow joint is attached to the proximal, anterior
surface of the olecranon, and the tendon of triceps is attached to its
rough posterior two-thirds; the capsule and tendon may be separated
by a bursa. The medial surface of the olecranon is marked proximally
Pronator crest Anterior interosseous by the attachment of the posterior and oblique bands of the ulnar col-
artery piercing interosseous lateral ligament and by the ulnar part of flexor carpi ulnaris. The smooth
Terminal branches membrane area distal to this is the most proximal attachment of flexor digitorum
of anterior interosseous nerve profundus. Anconeus is attached to the lateral surface of the olecranon
Triangular area and the adjoining posterior surface of the ulnar shaft as far as its oblique
line. The posterior surface of the ulna is separated from the skin by a
Head of ulna
subcutaneous bursa.
Styloid process Brachialis is attached to the anterior surface of the coronoid process,
of ulna including the ulnar tuberosity. The oblique and anterior bands of the
Styloid process ulnar collateral ligament and the distal part of the humero-ulnar slip
Fig. 49.10 The interosseous membrane and oblique cord of the forearm: of flexor digitorum superficialis are attached to a small tubercle at the
anterior aspect. Membrane and cord are syndesmoses. proximal end of the medial border. Further distally, the margin of the
coronoid process provides attachment for the ulnar head of pronator
teres. An ulnar head of flexor pollicis longus may be attached to the
lateral or, more rarely, the medial, border of the coronoid process.
Fig. 49.11 The proximal Fibres of flexor digitorum profundus are attached to its medial surface.
1 end of the left ulna: lateral The anular ligament is attached to the anterior rim of the radial notch
view. Key: 1, olecranon; and, posteriorly, to a ridge at, or just behind, the posterior margin of


2, non-articular strip in
the notch. The depressed area distal to the notch is limited behind by
trochlear notch; 3, coronoid
the supinator crest, and both provide attachment for supinator.
process; 4, tuberosity; 5,
5 The olecranon area of the trochlear notch is usually divided into
2 trochlear notch; 6, radial
three areas. The most medial faces anteromedially, and is grooved to fit
notch; 7, supinator crest; 8,
the medial flange of the humeral trochlea, with which it makes increas-
shaft.
3 ing contact during flexion. A flat intermediate area fits the lateral flange.
6 The most lateral area is a narrow strip that abuts the trochlea in exten-
sion. The articular surface is narrower than the base of the olecranon;
non-articular areas are related to the synovial processes. The coronoid
area of the trochlear notch is also divided; its medial and lateral areas
correspond to the medial and intermediate areas of the olecranon. The
medial is the deeper, and conforms to the convex medial trochlear
flange. The medial and anterior parts of the capsular ligament are
4 attached to its medial and anterior borders.
7
The deep fascia of the forearm is attached to the subcutaneous pos-
terior border, which also provides an attachment for the aponeurosis
of flexor digitorum profundus in its proximal three-quarters, for flexor
carpi ulnaris in its proximal half, and for extensor carpi ulnaris in its
middle third. These three muscles are attached to the posterior border
through a common blended aponeurosis. The interosseous membrane
is attached along the interosseous border, except for a short length
proximally.
8 Flexor digitorum profundus is attached to the proximal three-
quarters of the anterior border and medial surface, arising medial to the


Joints
843
94
rETPaHC
coronoid process and olecranon. The rough strip across the distal fourth and sixth year in males, and extends into the styloid process. The distal
of the anterior surface provides part of the bony attachment for prona- olecranon is ossified as an extension from the shaft, the remainder from
tor quadratus. Anconeus is attached to the posterior surface proximal two centres, one for the proximal trochlear surface and the other for a
to the oblique line and lateral to the olecranon. The narrow strip thin, scale-like proximal epiphysis on its summit. The proximal epiphy-
between the interosseous border and vertical ridge gives rise to the sis appears in the ninth year in females and eleventh year in males, and
attachment of three deep muscles: abductor pollicis longus arises from the whole proximal epiphysis has usually joined the shaft by the four-
the proximal quarter, extensor pollicis longus from the succeeding teenth year in females and sixteenth year in males. The distal epiphysis
quarter (sometimes a ridge is interposed between them), and extensor usually unites with the shaft in the seventeenth year in females and
indicis from the third quarter. Extensor carpi ulnaris covers the broad eighteenth in males. Along with the distal humerus, the proximal ulna
strip medial to the vertical ridge and its tendon grooves the posterior ossifies in a sequential manner; skeletal maturity may be assessed by
aspect of the distal end of the ulna. observations of elbow radiographs.
Vascular supply
The ulna receives its vascular supply from branches of the radial, ulnar, JOINTS
anterior and posterior interosseous arteries via multiple metaphysial
nutrient foramina. Usually one, but occasionally two, major nutrient
The elbow joint acts as a platform for the forearm and hand. The
diaphysial foramina are located on the anterior surface of the bone,
humero-ulnar and humero-radial joints form a complex hinge that
directed proximally towards the elbow. A network of small fascioperio-
enables flexion and extension of the forearm. The humero-radial joint,
steal and musculoperiosteal branches given off from the compartmen-
in conjunction with the proximal and distal radio-ulnar joints, allows


tal vessels reaches the bone via septal and muscular attachments.
full pronation and supination of the forearm. The configuration of the
humero-ulnar joint, between the trochlea and the trochlear notch of
Ossification
the ulna and the distal prolongation of the medial edge of the trochlear
The ulna ossifies from four main centres: one each in the shaft and
pulley, tilts the ulna, forming a ‘carrying angle’ (approximately 14° in
distal end, and two in the olecranon (see Fig. 48.13; Fig. 49.12). Ossi-
women and 11° in men) between the longitudinal axes of the humerus
fication begins in the midshaft about the eighth fetal week and extends
and ulna when the elbow is fully extended and supinated. These axes
rapidly. A centre appears in the distal end in the fifth year in females
become aligned in full flexion.
HUMERO-ULNAR JOINT
1 The humero-ulnar joint is a complex hinge joint and is continuous with
two pivot joints between the distal humerus and proximal radius, and
1
5 between the proximal radius and ulna (Figs 49.13, 49.15–17). There is
a high degree of congruity between the deep trochlea of the humerus
2 6 3 and the large trochlear notch of the ulna. This stable arrangement is
7
enhanced by strong medial and lateral collateral ligaments and, in full
3
extension, by the anterior capsule. An arc of 150° of flexion and exten-
1 sion is possible. A range of 180° of pronation and supination is
achieved by synchronous movements at the proximal and distal radio-
ulnar joints, aided by minor contributions from the radiocarpal and
carpal joints.
Articulating surfaces The distal humerus possesses two distinct
articulating surfaces: the humeral trochlea and the capitulum (see Fig.
49.3). The shape of the humeral trochlea is asymmetric, with a longer
medial flange. It is widest posteriorly in the adult. The joint line lies
2 cm distal to the interepicondylar line and is tilted inferomedially. The
flexion–extension arc of elbow movement is not a simple hinge. Differ-