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APPLIED AND CLINICAL ANATOMY OF THE UPPER LIMB
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•

Recognize the major palpable and imaging features of the bones of upper limb

•

Be aware of the sites of common fractures and the complication that might result from
them
...


•

Demonstrate the course, key relations and distribution of the main neurovascular
structures

•

Demonstrate the major pulse points, the position of major veins
...


•

Be able to explain the anatomical basis of common condition of the upper limb and how
infection might spread in the limb
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It is modified skin gland & rudimentary in males
...

It extends from the 2nd rib to 6th rib & from the edge of sternum to the mid-axillary line
...


Blood supply
1
...

2
...

3
...
The venous drainage is to the corresponding veins
...
N
...
N
...
Lymphatic drainage of the breast assumes great importance to the
surgeon because carcinoma of the breast spreads mostly along lymphatic to the regional
lymph nodes
...
Anterior group—lying deep to pectoralis major along the lower border of pectoralis
minor;
2
...
Lateral group—along the axillary vein;
4
...
apical group (through which all the other axillary nodes drain)—immediately behind the
clavicle at the apex of the axilla above pectoralis minor and along the medial side of the
axillary vein
...
The superficial lymphatics: this drain the skin over the breast except for the nipple and
areola
...

B
...
They also drain the nipple
and areola
...

HOW DOES MALIGNANT SPREAD OCCOUR?

From the apical nodes emerges the subclavian lymph trunk
...
When this normal pathways is interrupted by malignant
deposits, surgery or radiotherapy, lymphatic spread of a growth of the breast may occur
further away
...

PARTS OF THE UPPER LIMB
The upper is made up of 4 parts:

1
...

2
...

3
...

4
...

The bones and joints of the upper limb
THE SCAPULA

•

It is a flat bone with 2 surfaces (ventral& dorsal)
...
& 3 borders (medial ,lateral & superior)
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•

Its strong muscular coverings protect the scapula and it is rarely fractured, only by direct
and severe violence
...

1-The synovial joints :
1-The glenoid cavity with the head of the humerus to form the shoulder joint
...

•

It has no medullary cavity
...


•

Although a long bone, it develops in membrane and not in cartilage
...
Medially it articulates
with the manubrium at the sternoclavicular joint, and is also attached to, the first costal cartilage
by the costoclavicular ligament
...
The third parts of the subclavian vessels and the trunks of the brachial
plexus pass behind the medial third of the shaft of the clavicle, separated only by the thin
subclavius muscle
...

IMPORTANT POSTERIOR RELATIONS
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
...
These vessels are
separated from bone by the strap muscles—the sternohyoid and sternothyroid
...
To transmit forces from the upper limb to the axial skeleton;
2
...
To provide attachment for muscles
...

Transmission of forces to the axial skeleton in falls on the shoulder or hand may prove greater
than the strength of the bone at this site and this indirect force is the usual cause of fracture
...
The lateral fragment is not only depressed but also
drawn medially by the shoulder adductors, principally the teres major, latissimus dorsi and
pectoralis major

THE HUMERUS
The upper end of the humerus consists of a head facing medially, upwards and backwards,
separated from the greater and lesser tubercles by the anatomical neck
...
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 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 profunda vessels
...

The medial and lateral epicondyles, on either side, are extra-capsular; the medial is the larger of
the two, extends more distally and bears a groove on its posterior aspect for the ulnar nerve
...
It is an important practical point to note that the lower end of the
humerus is angulated forward 45° on the shaft
...
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 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
...
This axis of
rotation passes from the radial head proximally to the
ulnar head distally
...
The pronator teres is inserted midway along the radial shaft
...
The fracture must, therefore, be splinted
with the forearm supinated so that the distal fragment is aligned with the supinated
proximal end
...


2
...
In the last injury, the radius fractures about 1|in (2
...
The shortening which
results brings the styloid processes of the radius and ulna more or less in line with each other
...
The olecranon process may be fractured by direct violence but more often it is avulsed by
forcible contraction of the triceps, which is inserted into its upper aspect
...

4
...

4
...
Students and coal

miners share this hazard so that olecranon bursitis goes by the nicknames of ‘student’s elbow’
and ‘miner’s elbow’
...

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 is inserted
...
The carpus as a whole is arched transversely, the palmar aspect being concave
...


CLINICAL FEATURES
1
...
This occur when a fall on the hand may dislocate the
rest of the carpal arch backwards from the lunate which, as commented on above, is
wide-based anteriorly
...
The scaphoid may be fractured by a fall on the palm with the hand abducted, in which
position the scaphoid lies directly facing the radius
...


THE SHOULDER JOINT
The shoulder is a ball-and-socket joint between the relatively large head of humerus and
relatively small and shallow glenoid fossa
...
The closely related short muscles of the ‘rotator cuff’
...
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
...


NB, Rotator cuff 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
...
All originate from the scapula
...
It passes over
the apex of the shoulder beneath the acromion process and coracoacromial ligament,
from which it is separated by the subacrominal bursa
...

Clinical features

•

Dislocation of the shoulder
The wide range of movement possible at the shoulder is achieved only at the cost of
stability, and for this reason it is the most commonly dislocated major joint
...
The axillary nerve, lying in relation to
the surgical neck of the humerus, may be torn in this injury
...
The elbow is then swung medially across the trunk, thus levering the
head of the humerus laterally so that it slips back into place
...

The elbow joints

The elbow joint, although a single synovial cavity, is made up of three distinct
articulations, which are:
1
...
the humeroradial, between the capitulum and the upper concave surface of the radial head
(a ball and socket joint);
3
...

The capsule of the elbow joint is closely applied around this complex articular
arrangement; the non-articular medial and lateral epicondyles are extracapsular
...
The lateral ligament is attached distally to the annular ligament around the
radial head
...

Two sets of movements take place at the elbow:
1
...
pronation and supination at the proximal radio-ulnar (in conjunction with associated
movements of the distal radio-ulnar joint)
...
When the biceps contracts, not only is the forearm flexed, but the
radius ‘unwinds’ as its tuberosity is rotated anteriorly, i
...
the forearm supinates Biceps is
a powerful muscle, hence supination is more powerful than pronation
...
The elbow joint is safely approached by a vertical posterior incision which divides the
triceps expansion
...
As the capsule is relatively weak anteriorly and posteriorly it will be distended at these
sites by an effusion, particularly posteriorly, since the anterior aspect is covered by
muscles and dense deep fascia
...

3
...
A sudden jerk on the arm of a child under the age of 8years may subluxate the

radial head through this ligament (‘pulled elbow’)
...

4
...

5
...
Characteristically, the triangular relationship
between the olecranon and the two humeral epicondyles is lost
...

NB, Because of the greater distal projection of the radial styloid, the range of
abduction at the wrist is considerably less than that of adduction
...
Flexion
and extension are increased by associated sliding movements of the intercarpal joints;
although the range of flexion at the wrist is actually less than that of extension, these
associated movements make it apparently greater
...

The carpometacarpal joint of the thumb is saddle-shaped and permits flexion and
extension (in a plane parallel to the palm of the hand), abduction and adduction (in a
plane at a right angle to the palm) and opposition, in which the thumb is brought across in
contact with the 5th finger
...

The opposite state of affairs holds at the metacarpophalangeal (m/p) joints; only a 60°
range of flexion and extension is possible at the m/p joint of the thumb, whereas a 90°
range of flexion and extension, together with abduction, adduction and circumduction,
are possible at the four other m/p joint’s, which are condyloid in shape
...
This
is because each metacarpal head, although rounded at its distal extremity, is flattened
anteriorly; when the base of the proximal phalanx moves on to this flattened surface, side
movements become impossible
...

The m/p joints of the fingers, but not the thumb, are linked by the tough deep transverse
ligaments, which prevent any spreading of the palm when a firm grip is taken
...
At all the m/p and i/p joints the ligamentous
arrangements are the same
...
Posteriorly—the joint capsule is replaced by the expansion of the extensor tendon of the
digit concerned
2
...

3
...

The long flexors of the fingers are:
1
...
flexor digitorum superficialis, inserted into the sides of the four middle phalanges
...

The profundus flexes the distal phalanx, superficialis the middle phalanx; acting together
they flex the fingers and the wrist
The long extensors of the fingers are
...
extensor digitorum longus, reinforced by;
2
...
extensor digiti minimi } extensor digitorum longus on their medial sides
...
It
then attaches by a central slip into the base of the middle phalanx and by two lateral slips
to the distal phalanx
The margins of the extensor expansions are reinforced by the tendons of the intrinsic
muscles of the fingers:
1
...
The lumbricals, which arise from the four profundus tendons and run on the radial side
of the m/p joints to join the extensor expansion
...
The interossei, together with abductor digiti minimi, are responsible
for abduction (dorsal interossei) and adduction (ventral interossei) of the fingers
...
However, if these movements of
extension and flexion are eliminated by laying the hand flat on the table, abduction and
adduction become purely the actions of the intrinsic muscles
...

The 5th finger receives two further intrinsic muscles, opponens digiti minimi and flexor
digiti minimi, from the hypothenar eminence
The flexors and extensors of the wrist play an important synergic role in movements of
the hand
...

THE ARTERIS OF THE UPPER LIMB
The axillary artery:
The axillary artery commences at the lateral border of the first rib, as a continuation of
the subclavian, and ends at the lower border of the axilla (i
...
the lower border of teres
major) to become the brachial artery
...
Above pectoralis
minor, the brachial plexus lies above and behind the artery, but, distal to this, the cords
of the plexus take up their positions around the artery according to their names, i
...

lateral, medial and posterior
...


All but the circumflex humeral

vessels are encountered in the axillary dissection of a radical mastectomy
...
It is
superficial (immediately below the deep fascia) along its whole course,

except where it is crossed, at the level of the middle of the humerus, by the
median nerve which passes superficially from its lateral to medial side;
occasionally the nerve crosses deep to the artery
...

The named branches of the artery are:
i
...


superior ulnar collateral(accompanying the ulnar nerve);

iii
...


inferior ulnar collateral
...
In its upper half it lies overlapped by brachioradialis, the surface marking of the
artery being the groove which can be seen on the medial side of this tensed muscle in the
muscular subject
...
In the middle third of the forearm the radial nerve lies along the
lateral side of the artery; the nerve may here be incorporated in a carelessly placed
ligature
...
It then passes deep to the tendons of abductor pollicis longus and extensor
pollicis brevis to enter the anatomical snuff-box (in which it can be felt), pierces the first
dorsal interosseous muscle and adductor pollicis, between the 1st and 2nd metacarpals,
and goes on to form the deep palmar arch with the deep branch of the ulnar artery
...
From its commencement it passes beneath the muscles arising from the
common flexor origin, lies upon flexor digitorum profundus and is overlapped by flexor
carpi ulnaris
...
In the distal half of the

forearm the artery becomes superficial between the tendons of flexor carpi ulnaris and
flexor digitorum sublimis; it then crosses the flexor retinaculum to form the superficial
palmar arch with the superficial branch of the radial artery
...
These superficial veins can be seen as a dorsal venous network on the back
of the hand which drains into a lateral cephalic and medial basilic vein
...

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 cutdown
...
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
...
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

The brachial plexus
The brachial plexus is of great practical importance to the surgeon
...
It is encountered, and hence put in danger, in operations upon the root of the
neck
...
five roots derived from the anterior primary rami of C5, 6, 7, 8 and T1;link up into:
2
...


C5 and 6 (upper);

ii
...


C8 and T1 (lower)

which split into:
3
...


three cords

i
...


a medial, from the anterior division of the lower trunk;

iii
...

The roots lie between the anterior and middle scalene muscles
...
The divisions lie behind the clavicle
...
The cords continue distally to form the main nerve trunks of the upper limb thus:

1
...
the medial cord, as the ulnar nerve;
3
...
a cross-communication between the lateral and medial cords forms the median nerve
...

From the roots
 nerve to rhomboids;
 nerve to subclavius;
 nerve to serratus anterior (C5, 6, 7)
...

•

From the lateral cord

 musculocutaneous nerve;
 lateral pectoral nerve;
 lateral root of median nerve
...

•

From the posterior cord

 subscapular nerves;
 nerve to latissimus dorsi (thoracodorsal nerve);
 axillary nerve;
 radial nerve
...

THE COURSE AND DISTRIBUTION OF THE PRINCIPAL NERVES OF THE
UPPER LIMB
The axillary nerve:
The axillary (circumflex) nerve (C5, 6) arises from the posterior cord of the plexus and
winds round the surgical neck of the humerus in company with the posterior circumflex
humeral vessels
...


muscular—to deltoid and teres minor;

ii
...

The axillary nerve may be injured in fractures of the humeral neck or in

dislocations of the shoulder
...

NB, The nerves of the upper limb are derived from the brachial plexus
...
Lying first
behind the axillary artery, it then passes backwards between the long and medial heads of
the triceps to lie in the spiral groove on the back of the humerus between the medial and
lateral heads of triceps
...
At the lower third of the
humerus, the radial nerve pierces the lateral intermuscular septum to re-enter the anterior
compartment of the arm between brachialis and brachioradialis (a convenient site for
surgical exposure),
...

The radial nerve itself continues as the superficial radial nerve, lying deep to
brachioradialis
...
The main
trunk itself innervates: triceps, anconeus, brachioradialis and extensor carpi radialis
longus
...
The posterior interosseous
branch supplies all the remaining extensor muscles of the forearm together with the
supinator and abductor pollicis longus
...
So great is the overlap from
adjacent nerves, however, that division of the radial nerve results, surprisingly, in only a
small area of anaesthesia over the dorsum of the hand, in the web between the thumb and
index finger
...

It pierces coracobrachialis then runs between biceps and brachialis (supplying all these
three muscles) to innervate, by its terminal cutaneous branch, now termed the lateral
cutaneous nerve of the forearm, the skin of the lateral forearm
...
It lies medial
to the axillary and brachial artery as far as the middle of the humerus, then pierces the
medial intermuscular septum (in company with the superior ulnar collateral artery) to
descend on the anterior face of triceps
...
Here it descends beneath
flexor carpi ulnaris until this muscle thins out into its tendon, leaving the nerve to lie
superficially on its radial side
...
About 2|in (5|cm)
above the wrist, a dorsal cutaneous branch passes deep to flexor carpi ulnaris to supply
the dorsal aspects of the ulnar 11/2 fingers and the dorsal aspect or the ulnar side of the
hand
...
Continuing along the lateral aspect of the brachial artery, the nerve then
crosses superficially (occasionally deep) to the artery at the mid-humerus to lie on its
medial side
...


Here the nerve gives off its anterior

interosseous branch (which supplies flexor pollicis longus, flexor digitorum profundus to
the index and middle fingers, and pronator quadratus), and then lies on the deep aspect of
flexor digitorum superficialis, to which it adheres
...
Here it gives off a palmar cutaneous branch, which
supplies the skin of the midpalm
...
Its branches are:
i
...


cutaneous—to the skin of the radial side of the palm, the palmar, and a variable degree of
the dorsal, aspect of the radial 31/2digits
...
Brachial plexus injuries may occur from traction on the

arm during birth
...
The arm, therefore, hangs limply by the side with
the forearm pronated and the palm facing backwards, like a porter hinting for a tip
...


Upward traction on the arm (e
...
in a forcible breech delivery) may tear the lowest root,
T1, which is the segmental supply of the intrinsic hand muscles
...
A mass of
malignant supraclavicular lymph nodes or the direct invasion of a pulmonary carcinoma
condition called Pancoast’s syndrome may produce a similar neurological picture by

involvement of the lowest root of the plexus
...

The radial nerve may be injured in the axilla by the pressure of a crutch resulting in
‘crutch palsy’ or may be compressed when a drunkard falls into an intoxicated sleep with
the arm hanging over the back of a chair (‘Saturday night palsy’)
...
Damage to the main trunk of the radial nerve results in a wrist drop
due to paralysis of all the wrist extensor
...
In the latter case, all the intrinsic muscles of the fingers (apart

from the radial two lumbricals) are paralysed so that the hand assumes the clawed
position already described under Klumpke’s palsy
The median nerve is occasionally damaged in supracondylar fractures but it is in greatest
danger in lacerations of the wrist
...
The best clinical test for this is to ask the patient, with his
hand resting palm upwards on the table, to touch a pencil held above the thumb
...
If
the median nerve is divided at the elbow, there is serious muscle impairment
...

Wrist flexion is weak and accompanied by ulnar deviation
...


Since the flexors of the wrist are bulkier than the extensors, their fibrous contraction is
greater and the wrist is therefore flexed
...


The long extensors of the fingers are inserted into the proximal phalanges; their
contracture extends the m/p joints
...


The long flexors are inserted into the distal and middle phalanges and therefore flex the
i/p joints
...

THE SPACES OF THE HAND
The spaces of the hand are of practical significance because they may become infected
and, in consequence, become distended with pus
...
The superficial pulp spaces of the fingers;
2
...
The ulnar bursa;

4
...
The midpalmar space;
6
...

1
...

The tips of the fingers and thumb are composed entirely of subcutaneous fat broken up
and packed between fibrous septa, which pass from the skin down to the periosteum of
the terminal phalanx
...




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