3: The Upper Limb

Part 3
The Upper Limb

Surface anatomy and surface markings of the upper limb

Much of the surface anatomy of the limbs can be studied on oneself, or on an obliging colleague with a suitable body mass index!

Bones and joints (see Figs 117, 119, 120, 122)

The subcutaneous border of the clavicle can be palpated along its entire length; the supraclavicular nerves crossing the surface of the clavicle can occasionally be felt against the underlying bone.

The acromion process forms a distinct bony edge at the lateral extremity of the scapular spine. It lies immediately above the smooth bulge of the deltoid muscle, which itself covers the greater tubercle of the humerus. Less easily identified is the coracoid process of the scapula, lying immediately below the clavicle at the junction of the middle and outer thirds, and covered by the anterior fibres of the deltoid.

The medial border of the scapula can be both seen and felt. Abduction of the arm is a complex affair made up of abduction at the shoulder joint, depression at the sternoclavicular joint and rotation of the scapula; the last two are readily confirmed by self‐palpation.

With the shoulder abducted, the head of the humerus can be felt at the apex of the axilla; note its movement with rotation of the arm.

At the elbow, the three bony landmarks are the olecranon process and the medial and lateral epicondyles. A supracondylar fracture lies above these points, which therefore remain in their triangular relationship to each other; in dislocation of the elbow, however, the olecranon comes to lie more or less in line with the epicondyles (Fig. 112).

Image described by caption.

Fig. 112 The relationship of the medial and lateral epicondyles to the olecranon process (a) is disturbed in a dislocation of the elbow (b) but maintained in a supracondylar fracture (c).

Note a hollow in the posterolateral aspect of the extended elbow distal to the lateral epicondyle; this lies over the head of the radius, which can be felt to rotate during pronation and supination.

The posterior border of the ulna is completely subcutaneous and crossed by no named vessels or nerve; it can therefore be exposed surgically from end to end without danger.

At the wrist, the styloid processes of the radius and ulna can be felt; the former extends more distally. The radial styloid lies in the floor of the ‘anatomical snuffbox’, while the ulnar styloid can be felt (and usually seen) on the dorsal aspect of the head of the ulna. The dorsal tubercle of Lister is palpable on the posterior aspect of the distal end of the radius.

In the palm of the hand, palpate the pisiform at the base of the hypothenar eminence. Flexor carpi ulnaris is inserted into it and when this tendon is relaxed by flexing the wrist the pisiform can be moved a little from side to side. The hook of the hamate can be felt by deep palpation just disto‐radial to the pisiform. The scaphoid is felt at the base of the thenar eminence and also within the anatomical snuffbox, where there is characteristic tenderness when this bone is fractured. In a thin subject, the pisiform and the tubercle of the scaphoid can be seen as bulges when the wrist is extended.

Muscles and tendons

The anterior fold of the axilla is formed by the pectoralis major, and the posterior fold of the axilla by the teres major and latissimus dorsi. The digitations of serratus anterior can be seen in a muscular subject on the medial axillary wall.

In the upper arm the deltoid forms the smooth contour of the shoulder. The biceps and brachialis constitute the bulk of the anterior aspect of the arm, and the triceps its posterior aspect. The tendon of biceps is easily felt, and often seen, at the elbow when this is flexed to a right angle. Immediately medial to this, palpate the pulse of the brachial artery. Firm pressure immediately medial to this will, in turn, produce paraesthesiae in the hand as the median nerve is palpated (see Fig. 134).

When the forearm is flexed against resistance, the brachioradialis presents prominently along its radial border.

At the wrist (Figs 113, 114, 115) it is convenient to commence at the radial pulse. The tendon medial to this is that of the flexor carpi radialis, then palmaris longus (which may be absent), then the cluster of tendons of flexor digitorum superficialis. The tendon of flexor carpi ulnaris lies most medially, inserting into the pisiform; the ulnar pulse can be felt just to the radial side of this tendon.

The structures on the anterior aspect of the right wrist with parts labeled flexor carpi radialis, radial artery, median nerve, thenar muscles, recurrent motor branch of median nerve, palmaris longus, etc.

Fig. 113 The structures on the anterior aspect of the right wrist.

The structures on the posterior aspect of the right wrist with parts labeled extensor digiti minimi, extensor carpi ulnaris, extensor digitorum, abductor pollicis longus, extensor pollicis brevis, etc.

Fig. 114 The structures on the posterior aspect of the right wrist.

Section immediately above the wrist joint, with parts labeled median nerve, flexor pollicis longus, flexor carpi radialis, radial artery, abductor pollicis longus, extensor pollicis brevis, extensor pollicis longus, etc.

Fig. 115 Section immediately above the wrist joint.

On the dorsal aspect of the wrist (Figs 114, 115) the anatomical snuffbox is bordered by the tendons of abductor pollicis longus and extensor pollicis brevis laterally and that of extensor pollicis longus medially (i.e. towards the ulnar border) – the last can be traced to the base of the terminal phalanx of the extended thumb. The tendons of extensor digitorum are seen in the extended hand passing over the dorsal aspects of the proximal phalanges of the fingers.


Feel the pulsations of the subclavian artery against the first rib, the brachial artery against the humerus, the radial and ulnar arteries at the wrist and the radial artery again in the anatomical snuffbox.

The brachial artery bifurcates into its radial and ulnar branches at the level of the neck of the radius and the line of the radial artery then corresponds to the slight groove which can be seen along the ulnar border of the tensed brachioradialis.

The veins of the upper limb (Fig. 116) comprise the deep venae comitantes, which accompany all the main arteries, usually in pairs, and the much more important superficial veins – more important both in size and in practical value because of their use for venepuncture and transfusion.

Image described by caption.

Fig. 116 (a) The cubital fossa with the bicipital aponeurosis in detail. (b) The superficial veins of the upper limb. (Note the bicipital aponeurosis situated between the median cubital vein and brachial artery.) (c) Two common arrangements in the formation of the median cubital vein.

These superficial veins can be seen as a dorsal venous network on the back of the hand that drains into a lateral cephalic and medial basilic vein.

The cephalic vein at its origin lies fairly constantly in the superficial fascia just posterior to the radial styloid; even if not visible it can be cut down upon confidently at this site. It then runs up the anterior aspect of the forearm to lie in a groove along the lateral border of the biceps and then, after piercing the deep fascia, in the groove between pectoralis major and the deltoid, where again it can readily be exposed for an emergency cut‐down. It finally penetrates the clavipectoral fascia to enter the axillary vein.

The basilic vein runs along the posteromedial aspect of the forearm, passes on to the anterior aspect just below the elbow and pierces the deep fascia at about the middle of the upper arm. At the edge of the posterior axillary fold it is joined by the venae comitantes of the brachial artery to form the axillary vein.

Linking the cephalic and basilic veins just distal to the front of the elbow is the median cubital vein, usually the most prominent superficial vein in the body and visible or palpable when all others are hidden in fat or collapsed in shock. It usually runs upwards and medially from the cephalic to the basilic vein, giving a rather drunken ‘H’‐shaped appearance, and receiving a median forearm vein. A frequent variant is for the median forearm vein to bifurcate just distal to the fossa – one branch passing to the cephalic, the other to the basilic vein – giving an ‘M’‐shaped pattern, which replaces the median cubital vein. Since this area is so often used in venepuncture, you will soon be familiar with these two appearances (Fig. 116b,c). It was the antecubital vein that was favoured for the operation of bleeding, or phlebotomy, in days gone by; the underlying brachial artery was protected from the barber–surgeon’s knife by the bicipital aponeurosis, a condensation of deep fascia passing across from the biceps tendon, which was therefore termed the ‘grâce à Dieu’ (praise be to God) fascia.

In more modern times one tries to avoid using this vein for injection of intravenous barbiturates and other irritant drugs because of the slight risk of entering the brachial artery and also because of the danger of piercing a superficially placed abnormal ulnar artery in occasional instances of high brachial artery bifurcation.


A number of nerves in the upper limb can be palpated, particularly in a thin subject; these are the supraclavicular nerves, as they pass over the clavicle, the cords of the brachial plexus against the humeral head (with the arm abducted), the median nerve in the mid‐upper arm, crossing over the brachial artery, the ulnar nerve in the groove of the medial epicondyle and the superficial radial nerve as it passes over the tendon of extensor pollicis longus at the wrist.

The median nerve lies first lateral then medial to the brachial artery, crossing it at the mid‐upper arm, usually superficially but occasionally deeply. This close relationship is of historical interest: Nelson (Lord (Viscount) Horatio Nelson (1758–1805) was one of England’s greatest heroes; he was the most inspiring leader ever to command the British Navy) had his median nerve accidentally incorporated in the ligature around the artery when his arm was amputated above the elbow.

Useful surface markings of other, impalpable, nerves may be listed as follows.

  1. The axillary nerve is related closely to the surgical neck of the humerus 5 cm (2 in) below the acromion process.
  2. The radial nerve crosses the posterior aspect of the humeral shaft at its mid‐point.
  3. The posterior interosseous branch of the radial nerve is located by Henry’s method as it winds round the radius. Place three fingers along the lateral aspect of the upper end of the radius; the uppermost finger lies on the radial head (feel it rotate on pronation and supination), and the lowermost lies over the nerve.
  4. The median nerve (Figs 113, 115) in the forearm lies, as its name suggests, in the median plane; its area of distribution in the hand is thus anaesthetized if local anaesthetic is injected exactly in the midline at the wrist.
  5. The ulnar nerve at the wrist lies immediately medial to the ulnar pulse (Figs 113, 115). In the hand, it passes on the radial side of the pisiform and then lies on the hook of the hamate. If you press with your fingernail just lateral to the pisiform bone, you will experience tingling in your ulnar two fingers.

The bones and joints of the upper limb

The scapula (Fig. 117)

Anterior aspect of the scapula and clavicle with labels Medial end of clavicle, superior angle, coracoid process, costal surface, area for coracoclavicular ligament, acromion process, glenoid fossa, etc.

Fig. 117 The left scapula and clavicle (anterior aspect).

This triangular bone bears three prominent features: the glenoid fossa laterally (which is the scapula’s contribution to the shoulder joint), the spine on its posterior aspect, projecting laterally as the acromion process, and the coracoid process on its anterior aspect.

Its strong muscular coverings protect the scapula and only rarely is it fractured, and then only as a consequence of direct and severe violence.

The clavicle (Fig. 117)

This long bone has a number of unusual features.

  1. It has no medullary cavity.
  2. It is the first to ossify in the fetus (5th–6th week).
  3. Although a long bone, it develops in membrane and not in cartilage.
  4. It is the most commonly fractured long bone in the body.

The clavicle is made up of a medial two‐thirds, which is circular in section and convex anteriorly, and a lateral one‐third, which is flattened in section and convex posteriorly.

Medially it articulates with the manubrium at the sternoclavicular joint, which contains a cartilaginous disc (an important, and often overlooked, structure). It is a ball‐and‐socket joint that moves reciprocally with the movements of the shoulder joint, around its fulcrum – the costoclavicular ligament. Put a finger on the medial end of your clavicle; raise your shoulder – the sternoclavicular joint is depressed; retract your shoulder – the sternoclavicular joint protracts, and so on. The patient may complain of a ‘painful stiff shoulder’ when he actually has arthritis of the sternoclavicular joint.

Laterally the clavicle articulates with the acromion at the acromioclavicular joint (the joint containing an incomplete articular disc) and, in addition, is attached to the coracoid process by the tough coracoclavicular ligament.

The third parts of the subclavian vessels and the trunks of the brachial plexus pass behind the middle third of the shaft of the clavicle, separated only by the thin subclavius muscle. Fractures of the clavicle are common, yet associated injury of the underlying subclavian vessels (except in penetrating gunshot wounds) is extremely rare because of the protection offered by this functionally insignificant slip of a muscle. Rarely, these vessels (protected by the subclavius) are torn by the fragments of a fractured clavicle; this was the cause of death of Sir Robert Peel (Prime Minister of the United Kingdom 1834–1835, and again 1841–1846) following a fall from his horse.

The sternal end of the clavicle has important posterior relations; behind the sternoclavicular joints lie the common carotid artery on the left and the bifurcation of the brachiocephalic artery on the right. The internal jugular vein lies a little more laterally on either side. These vessels are separated from bone by the strap muscles – the sternohyoid and sternothyroid.

The humerus (Fig. 119)

Image described by caption.

Fig. 119 The (a) anterior and (b) posterior views of the right humerus. (c) The humerus with its three major related nerves – axillary, radial and ulnar – all of which are in danger of injury in humeral fractures.

The upper end of the humerus consists of a head (one‐third of a sphere) facing medially, upwards and backwards, separated from the greater and lesser tubercles by the anatomical neck. The tubercles, in turn, are separated from each other by the bicipital groove (intertubercular sulcus) along which emerges the long head of biceps from the shoulder joint.

Where the upper end and the shaft of the humerus meet there is the narrow surgical neck against which lie the axillary nerve and circumflex humeral vessels. The shaft itself is circular in section above and flattened in its lower part. The posterior aspect of the shaft bears the faint spiral groove demarcating the origins of the medial and lateral heads of the triceps between which wind the radial nerve and the accompanying profunda vessels.

The lower end of the humerus bears the rounded capitulum laterally, for articulation with the radial head, and the spool‐shaped trochlea medially, articulating with the trochlear notch of the ulna.

The medial and lateral epicondyles, on either side, are extracapsular; the medial is the larger of the two, extends more distally and bears a groove on its posterior aspect for the ulnar nerve.

Three important nerves thus come into close contact with the humerus – the axillary, the radial and the ulnar; they may be damaged, respectively, in fractures of the humeral neck, midshaft and lower end (Fig. 119).

It is an important practical point to note that the lower end of the humerus is angulated forwards 45° on the shaft. This is easily confirmed by examining a lateral radiograph of the elbow, when it will be seen that a vertical line continued downwards along the front of the shaft bisects the capitulum. Any decrease of this angulation indicates backward displacement of the distal end of the humerus and is good radiographic evidence of a supracondylar fracture.

The radius and ulna (Fig. 120)

Anterior aspect of the right radius and ulna with parts labeled trochlear notch, head of radius, neck of radius, radial tuberosity, sharp interosseous border of radius, area for attachment of pronator teres, etc.

Fig. 120 The right radius and ulna – anterior aspect.

The radius consists of the head, neck, shaft (with its radial tuberosity) and expanded distal end. The ulna comprises olecranon, trochlear fossa, coronoid process (with its radial notch for articulation with the radial head), shaft and small distal head, which articulates with the medial side of the distal end of the radius at the inferior radio‐ulnar joint.

In pronation and supination, the head of the radius rotates against the radial notch of the ulna, the shaft of the radius swings round the relatively fixed ulnar shaft (the two bones being connected by a fibrous interosseous ligament) and the distal end of the radius rotates against the head of the ulna. This axis of rotation passes from the radial head proximally to the ulnar head distally.

The bones of the hand (Fig. 122)

Anterior aspect of the right carpus, metacarpus and phalanges, with parts labeled lunate, pisiform, triquetral, hamate, base of 5th metacarpal, head of 4th metacarpal, distal phalanx, middle phalanx, etc.

Fig. 122 The right carpus, metacarpus and phalanges (anterior aspect).

The carpus is made up of two rows, each containing four bones. In the proximal row, from the lateral to the medial side, are the scaphoid, lunate and triquetral, the last bearing the pisiform on its anterior surface, into which sesamoid bone the flexor carpi ulnaris tendon is inserted.

In the distal row, from the lateral to the medial side, are the trapezium, trapezoid, capitate and hamate.

The carpus as a whole is arched transversely, the palmar aspect being concave. This is maintained by:

  1. the shapes of the individual bones, which are broader posteriorly than anteriorly (except for the lunate, which is broader anteriorly);
  2. the tough flexor retinaculum passing from the scaphoid and the ridge of the trapezium laterally to the pisiform and the hook of the hamate medially (Fig. 123);
  3. distal to the carpal bones lie the five metacarpals, slender bones apart from the first – that of the thumb, which is stout and set at right angles to the palm of the hand. In front of the head of this metacarpal are two tiny sesamoid bones (in the insertions of the heads of flexor pollicis longus), which are easily visible on a plain radiograph of the hand. Distally, the metacarpals articulate with the phalanges, of which there are two in the thumb and three in each of the other four fingers (Fig. 122). The important articulations between these small bones of the hand are considered on page 186.
Image described by caption.

Fig. 123 Transverse section through the distal carpus (right side viewed from the distal end), showing the attachments of the flexor retinaculum. Note the separate osseofascial compartment for the tendon of flexor carpi radialis. Note also that, at this level, the tendon of flexor carpi ulnaris has ‘disappeared’. It attaches to the pisiform, in the proximal row of carpal bones.

The shoulder joint (Figs 125, 126)

The left shoulder joint viewed from the lateral aspect, with parts labeled acromioclavicular joint, coracoacromial ligament, acromion, long head of biceps, glenoid fossa, labrum glenoidale, etc.

Fig. 125 The left shoulder joint (viewed from the lateral aspect) – its ligaments are shown after removal of the humerus.

The left shoulder joint viewed from the lateral aspect, similar to Figure 125, but with addition of the surrounding muscles, including supraspinatus, infraspinatus, teres minor, and long head of triceps.

Fig. 126 The shoulder joint – the same view as in Fig. 125, but now with the addition of the surrounding muscles.

The shoulder joint (glenohumeral joint) is a typical synovial joint of the ball‐and‐socket type, between the relatively large head of humerus and the relatively small and shallow glenoid fossa, although the latter is deepened somewhat by the cartilaginous ring of the labrum glenoidale.

The joint capsule is lax and is attached around the epiphyseal lines of both the glenoid and the humeral head. However, it does extend down on to the diaphysis on the medial aspect of the neck of the humerus, so that an osteomyelitis of the upper end of the humeral shaft may involve the joint by direct spread.

The capsule is lined on the inside by synovial membrane, which is prolonged along the tendon of the long head of the biceps as this traverses the joint. The synovium also communicates with the subscapular bursa beneath the tendon of subscapularis.

The stability of the shoulder joint depends almost entirely on the strength of the surrounding muscles, which may be grouped into:

  1. the closely related short muscles of the ‘rotator cuff’ (see following section);
  2. the long head of biceps, arising from the supraglenoid tubercle and crossing over the head of the humerus, thus lying actually within the joint, although enclosed in a tube of synovium;
  3. the more distantly related long muscles of the shoulder: the deltoid, long head of triceps, pectoralis major, latissimus dorsi and teres major.

Movements of the shoulder girdle

The movements of the shoulder joint itself cannot be divorced from those of the whole shoulder girdle. Even if the shoulder joint is fused, a wide range of movement is still possible by elevation, depression, rotation and protraction of the scapula, leverage occurring at the sternoclavicular joint, the pivot being the costoclavicular ligament.

Abduction of the shoulder is initiated by the supraspinatus; the deltoid can then abduct to 90°. Further movement to 180° (elevation) is brought about by rotation of the scapula upwards by the trapezius and serratus anterior. Shoulder and shoulder girdle movements combine into one smooth action. As soon as abduction commences at the shoulder joint, so rotation of the scapula begins. Test this on yourself or on a colleague by palpating the lower pole of the scapula. This will be felt to swing outwards on initiation of shoulder abduction. Movements of the scapula occur with reciprocal movements at the sternoclavicular joint. Place a finger on this joint; elevate the shoulder and the joint will be felt to depress; swing the shoulder forwards and it will be felt to move backwards, and so on.

Rotator cuff (Figs 126, 127) is the name given to the sheath of tendons of the short muscles of the shoulder which covers and blends with all but the inferior aspect of that joint. The muscles are the supraspinatus, infraspinatus and teres minor, which are inserted from above down into the humeral greater tubercle, and the subscapularis, which is inserted into the lesser tubercle. All originate from the scapula.

Image described by caption.

Fig. 127 (a) Supraspinatus and the subacromial–subdeltoid bursa. Note that the supraspinatus tendon lies close against the acromion – if this tendon is inflamed, there is a painful arc of movement as the shoulder is abducted from 60° to 120°, because, in this range, the inflamed tendon impinges against the acromion. (b) Magnetic resonance imaging of the shoulder showing the detailed anatomy revealed by this technique.

Of these muscles, the supraspinatus is of the greatest practical importance. It passes over the apex of the shoulder beneath the acromion process and coracoacromial ligament, from which it is separated by the subacromial bursa. This bursa is continued beneath the deltoid as the subdeltoid bursa forming, together, the largest bursa in the body.

The supraspinatus initiates the abduction of the humerus on the scapula; if the tendon is torn as a result of injury, active initiation of abduction becomes impossible and the patient has to develop the trick movement of tilting his body towards the injured side so that gravity passively swings the arm from his trunk. Once this occurs, the deltoid and the scapular rotators can then come into play.

Inflammation of the supraspinatus tendon (‘supraspinatus tendinitis’) is characterized by a painful arc of shoulder movement between 60° and 120°; in this range, the tendon impinges against the overlying acromion and the coracoacromial ligament. The investigation of soft‐tissue lesions around the shoulder has been greatly facilitated by magnetic resonance imaging (MRI), which reveals the anatomical structures in exquisite detail (Fig. 127b).

Principal muscles acting on the shoulder joint

Abductors Adductors
supraspinatus (initiates)
pectoralis major
latissimus dorsi
Flexors Extensors
biceps brachii
pectoralis major
deltoid (anterior fibres)
triceps brachii
teres major
latissimus dorsi
deltoid (posterior fibres)
Medial rotators Lateral rotators
pectoralis major
latissimus dorsi
teres major
deltoid (anterior fibres)
teres minor
deltoid (posterior fibres)

Jun 28, 2019 | Posted by in ANATOMY | Comments Off on 3: The Upper Limb

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