Upper Limb Clinical Anatomy

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Fracture of the clavicle

It may cause injury to the brachial plexus (lower trunk), causing paresthesia (sensation of
tingling, burning, and numbness) in the area of the skin (medial brachial and antebrachial region)
supplied by spinal cord segments C8 and T1, and may also cause fatal hemorrhage from the
subclavian vein and is responsible for thrombosis of the subclavian vein, leading to pulmonary
embolism.

Calcification of the superior transverse scapular ligament

may trap or compress the
suprascapular nerve as it passes through the scapular notch under the superior transverse
scapular ligament, affecting functions of the supraspinatus and infraspinatus muscles.

Fracture of the greater tuberosity

occurs by direct trauma or by violent contractions of the
supraspinatus muscle. The bone fragment has the attachments of the supraspinatus, infraspinatus, and teres minor muscles, whose tendons form parts of the rotator cuff.

Fracture of the lesser tuberosity

accompanies posterior dislocation of the shoulder joint, and the
bone fragment has the insertion of the subscapularis tendon.

Fracture of the surgical neck

may injure the axillary nerve and the posterior humeral circumflex
artery as they pass through the quadrangular space.

Fracture of the shaft

may injure the radial nerve and deep brachial artery in the spiral groove.

Supracondylar fracture:

is a fracture of the distal end of the humerus; it is common in children
and occurs when the child falls on the outstretched hand with the elbow partially flexed and may
injure the median nerve.

Fracture of the medial epicondyle

may damage the ulnar nerve. This nerve may be compressed in a groove behind the medial epicondyle "funny bone," causing numbness

Colles' fracture of the wrist

is a fracture of the lower end of the radius in which the distal
fragment is displaced (tilted) posteriorly, producing a characteristic bump described as dinner
(silver) fork deformity because the forearm and wrist resemble the shape of a dinner fork. If the
distal fragment is displaced anteriorly, it is called a reverse Colles' fracture (Smith's fracture).

Fracture of the scaphoid

occurs after a fall on the outstretched hand and may damage the radial
artery and cause avascular necrosis of the bone and degenerative joint disease of the wrist.

Fracture of the hamate

may injure the ulnar nerve and artery because they are in close proximity
to the hook of the hamate.

Guyon's canal syndrome

is an entrapment of the ulnar nerve in the Guyon's canal, which
causes pain, numbness, and tingling in the ring and little fingers, followed eventually by loss of
sensation and motor weakness. It can be treated by surgical decompression of the nerve.

Guyon's canal (ulnar tunnel)

is formed by the pisiform, hook of the hamate, and pisohamate
ligament, deep to the palmaris brevis and palmar carpal ligament and transmits the ulnar nerve and
artery. Within the tunnel, the nerve is divided into superficial and deep branches.

Dislocation of the acromioclavicular joint

results from a fall on the shoulder with the impact
taken by the acromion or from a fall on the outstretched arm. It is called a shoulder separation
because the shoulder is separated from the clavicle when the joint dislocation with rupture of the
coracodavicular ligament occurs.

Dislocation (subluxation) of the shoulder joint

occurs usually in the anteroinferior direction due
to lack of support by tendons of the rotator cuff. It may damage the axillary nerve and the posterior
humeral circumflex vessels.

Referred pain to the shoulder

most probably indicates involvement of the phrenic nerve (or
diaphragm). The supraclavisscular nerve (C3-C4), which supplies sensory fibers over the shoulder,
has the same origin as the phrenic nerve (C3-C5), which supplies the diaphragm

Rupture of rotator cuff

may occur by a chronic wear and tear or an acute fall on the outstretched
arm and is manifested by severe limitation of shoulder joint motion but chiefly abduction. A rupture
of the rotator cuff, particularly attrition of the supraspinatus tendon by friction among middle-aged persons, ultimately causes degenerative inflammatory changes (degenerative tendonitis) of the rotator cuff, or this attrition of the supraspinatus tendon and the underlying joint capsule leads to an open communication between the shoulder joint cavity and the subacromial bursa, which is subject
to inflammation (subacromial bursitis and supraspinatus tendinitis), resulting in a painful
abduction of the arm or a painful shoulder.

Mammography

is a radiographic exam ination of the breast to screen for benign and malignant
tumors and cysts. It plays a central part in early detection of breast cancers.

Breast cancer

occurs in the upper lateral quadrant (about 60% of cases) and forms a palpable mass in advanced stages. It enlarges, attaches to Cooper's ligaments, and produces shortening of the ligaments, causing depression or dimpling of the overlying skin. It may also attach to and shorten the lactiferous ducts, resulting in a retracted or inverted nipple. It may invade the deep
fascia of the pectoralis major muscle, so that contraction of the muscle produces a sudden upward movement of the entire breast.

Radical mastectomy

is extensive surgical removal of the breast and its related structures,
including the pectoralis major and minor muscles, axillary lymph node sand fascia, and part of the
thoracic wall. It may injure the long thoracic and thoracodorsal nerves and may cause postoperative swelling (edema) of the upper limb as a result of lymphatic obstruction caused by removal of most of the lymphatic channels that drain the arm or by venous obstruction caused by thrombosis of the axillary vein.

Modified radical mastectomy

involves excision of the entire breast and axillary lymph nodes,
with preservation of the pectoralis major and minor muscles. (The pectoralis minor muscle is
usually retracted or severed near its insertion into the coracoid process.)

Lumpectomy (tylectomy)

is surgical excision of only the palpable mass in carcinoma of the
breast.

Tennis elbow (lateral epicondylitis)

is caused by a chronic inflammation or irritation of the origin (tendon) of the extensor muscles of the forearm from the lateral epicondyle of the humerus as a result of unusual or repetitive strain. It is a painful condition and common in tennis players and
violinists.

Golfer's elbow (medial epicondylitis)

is a painful condition caused by a small tear or an inflammation or irritation in the origin of the flexor muscles of the forearm from the medial epicondyle. It is similar to tennis elbow, which affects the other side of the elbow. Treatment may include injection of glucocorticoids into the inflamed area or avoidance of repetitive bending (flexing) of the forearm in order to not compress the ulnar nerve.

Cubital tunnel syndrome

results from compression on the ulnar nerve in the cubital tunnel
behind the medial epicondyle (funny bone) causing numbness and tingling in the ring and little
fingers. The tunnel is formed by the medial epicondyle, ulnar collateral ligament, and two heads of
the flexor carpi ulnaris muscle and transmits the ulnar nerve and superior ulnar collateral or
posterior ulnar recurrent artery.

Dupuytren's contracture

is a progressive thickening, shortening, and fibrosis of the palmar fascia, especially the palmar aponeurosis, producing a flexion deformity of fingers in which the fingers are pulled toward the palm (inability to fully extend fingers), especially the third and fourth fingers.

Volkmann's contracture

is an ischemic muscular contracture (flexion deformity) of the fingers
and sometimes of the wrist resulting from ischemic necrosis of the forearm flexor muscles caused
by a pressure injury, such as compartment syndrome, or a tight cast. The muscles are replaced by
fibrous tissue, which contracts, producing the deformity.

Carpal tunnel syndrome

is caused by compression of the median nerve due to the reduced size of the osseofibrous carpal tunnel, resulting from inflammation of the flexor retinaculum, arthritic
changes in the carpal bones, or inflammation or thickening of the synovial sheaths of the flexor
tendons. It leads to pain and paresthesia (tingling, burning, and numbness) in the hand in the area
supplied by the median nerve and may also cause atrophy of the thenar muscles in cases of
severe compression. However, no paresthesia occurs over the thenar eminence of skin because
this area is supplied by the palmar cutaneous branch of the median nerve. Compression of cervical
nerves in the neck area exhibits a syndrome similar to the carpal tunnel syndrome.

Tenosynovitis:

is an inflammation of the tendon and synovial sheath, and puncture injuries cause infection of the synovial sheaths of the digits. The tendons of the second, third, and fourth digits have separate synovial sheaths so that the infection is confined to the infected digit, but
rupture of the proximal ends of these sheaths allows the infection to spread to the midpalmar
space. The synovial sheath of the little finger is usually continuous with the common synovial
sheath (ulnar bursa), and thus, tenosynovitis may spread to the common sheath and thus through
the palm and carpal tunnel to the forearm. Likewise, tenosynovitis in the thumb may spread through the synovial sheath of the flexor pollicis longus (radial bursa).

Trigger finger

results from stenosing tenosynovitis or occurs when the flexor tendon develops a nodule or swelling that interferes with its gliding through the pulley, causing an audible clicking or snapping. Symptoms are pain at the joints and a clicking when extending or flexing the joints. This condition may be caused by rheumatoid arthritis, diabetes, repetitive trauma, and wear and tear of ageing of the tendon. It can be treated by immobilization by a splint, an injection of corticosteroid
into the flexor tendon sheath to shrink the nodule, or surgical incision of the thickened area.

Mallet finger

(Hammer or baseball finger): is a finger with permanent flexion of the distal phalanx
due to an avulsion of the medial and lateral bands of the extensor tendon to the distal phalanx.

Boutonniere deformity:

is a finger with abnormal flexion of the middle phalanx and
hyperextension of the distal phalanx due to an avulsion of the central band of the extensor tendon
to the middle phalanx or rheumatoid arthritis.

Injury to the long thoracic nerve

is caused by a stab wound or during radical mastectomy or
thoracic surgery. It results in paralysis of the serratus anterior muscle and inability to elevate the
arm above the horizontal. It produces a winged scapula in which the vertebral (medial) border of the scapula protrudes away from the thorax.

Injury to the posterior cord

is caused by the pressure of the crosspiece of a crutch, resulting in
paralysis of the arm called crutch palsy. It results in loss in function of the extensors of the arm,
forearm, and hand and produces a wrist drop.

Injury to the axillary nerve

is caused by a fracture of the surgical neck of the humerus or inferior dislocation of the humerus. It results in weakness of lateral rotation and abduction of the arm (the supraspinatus can abduct the arm but not to a horizontal level).

Injury to the radial nerve

is caused by a fracture of the midshaft of the humerus. It results in loss of function in the extensors of the forearm, hand, metacarpals, and phalanges. It also results in loss of wrist extension, leading to wrist drop, and produces a weakness of abduction and
adduction of the hand.

Injury to the musculocutaneous nerve

results in weakness of supination (biceps) and forearm flexion (brachialis and biceps).

Injury to the median nerve

may be caused by a supracondylar fracture of the humerus or a
compression in the carpal tunnel. It results in loss of pronation, opposition of the thumb, and
flexion of the lateral two interphalangeal joints and impairment of the medial two interphalangeal joints. It also produces a characteristic flattening of the thenar eminence, often referred to as ape hand.

Injury to the ulnar nerve

is caused by a fracture of the medial epicondyle and results in a claw hand, in which the ring and little fingers are hyperextended at the metacarpophalangeal joints and
flexed at the interphalangeal joints. It results in loss of abduction and adduction of the fingers and
flexion of the metacarpophalangeal joints because of paralysis of the palmar and dorsal interossei
muscles and the medial two lumbricals. It also produces a wasted hypothenar eminence and palm and also leads to loss of adduction of the thumb because of paralysis of the adductor pollicis
muscle.

Upper trunk injury (Erb-Duchenne paralysis or Erb palsy)

is caused by a birth injury during a
breech delivery or a violent displacement of the head from the shoulder such as might result from a fall from a motorcycle or horse. It results in a loss of abduction, flexion, and lateral rotation of the
arm, producing a waiter's tip hand, in which the arm tends to lie in medial rotation resulting from
paralysis of lateral rotator muscles.

Lower trunk injury (Klumpke's paralysis):

may be caused during a difficult breech delivery (birth
palsy or obstetric paralysis), by a cervical rib (cervical rib syndrome), or by abnormal insertion or
spasm of the anterior and middle scalene muscles (scalene syndrome). The injury causes a claw hand.

If the axillary artery is ligated between the thyrocervical trunk and the subscapular artery, then?

then the blood from anastomoses in the scapular region arrives at the subscapular artery in which the blood flow is reversed to reach the axillary artery distal to the ligature. The axillary artery may be compressed or felt for the pulse in front of the teres major or against the humerus in the lateral
wall of the axilla.

If the brachial artery is tied off distal to the inferior ulnar collateral artery, then?

sufficient blood reaches
the ulnar and radial arteries via the existing anastomoses around the elbow. The brachial artery may be compressed or felt for the pulse on the brachialis against the humerus but medial to the biceps and its tendon and can be used for taking blood pressure.

Arterial blood pressure

can be measured by the following procedure. A blood pressure cuff is
placed around the arm and inflated with air until it compresses and occludes the brachial artery
against the humerus. A stethoscope is placed over the artery in the cubital fossa, the pressure in the cuff is gradually released, and the pulse is detected through the artery. The first audible spurt indicates systolic pressure. As the pressure in the cuff is further released, the point at which the
pulse can no longer be heard is the diastolic pressure.

If the ulnar artery arises high from the brachial artery and runs invariably superficial to the flexor muscles, then?

then when injecting, the artery may be mistaken for a vein for certain drugs, resulting in
disastrous gangrene with subsequent partial or total loss of the hand. The ulnar artery may be
compressed or felt for the pulse on the anterior aspect of the flexor retinaculum on the lateral side
of the pisiform bone.

Allen test

is a test for occlusion of the radial or ulnar artery; either the radial or ulnar artery is digitally compressed by the examiner after blood has been forced out of the hand by making a tight fist; failure of the blood to return to the palm and fingers on opening indicates that the uncompressed artery is occluded.

Venipuncture of the upper limb

is performed on veins by applying a tourniquet to the arm, when
the venous return is occluded and the veins are distended and are visible and palpable. Venipuncture may be performed on the axillary vein to locate the central line, on the median cubital vein for drawing blood, and on the dorsal venous network or the cephalic and basilic veins at their origin for long-term introduction of fluids or intravenous feeding.

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