Upper Limb

·         Clavicle is the first bone to begin ossification during fetal development, but it is the last one to complete ossification, at about age 21 years.

·         Boxer's fracture: is a fracture of the necks of the second and third metacarpals, seen in professional boxers, and typically of the fifth metacarpal in unskilled boxers.

·         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.

·         The suspensory ligament of the axilla, which is the inferior extension of the Clavipectoral fascia and is attached to the axillary fascia, maintaining the hollow of the armpit.

·         Teres Major – Lower Subscapular Nerve

Teres Minor – Axillary Nerve

·         A. Quadrangular space is bounded superiorly by the teres minor and subscapularis muscles, inferiorly by the teres major muscle, medially by the long head of the triceps, and laterally by the surgical neck of the humerus. Transmits the axillary nerve and the posterior humeral circumflex vessels.

B. Triangular space (upper) is bounded superiorly by the teres minor muscle, inferiorly by the teres 

major muscle, and laterally by the long head of the triceps. Contains the circumflex scapular vessels.

C. Triangular space (lower) is formed superiorly by the teres major muscle, medially by the long head of the triceps, and laterally by the medial head of the triceps. Contains the radial nerve and the profunda brachii (deep brachial) artery.

·         Anatomic snuffbox is a triangular interval bounded medially by the tendon of the extensor pollicis longus muscle and laterally by the tendons of the extensor pollicis brevis and abductor pollicis longus muscles.

·         Flexor retinaculum is crossed superficially by the ulnar nerve, ulnar artery, palmaris longus tendon, and palmar cutaneous branch of the median nerve.

·         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 posterior cord: is caused by the pressure of the crosspiece of a crutch, resulting in paralysis of the arm called crutch palsy.

·         Nerve to subclavius (C5) usually branches to the accessory phrenic nerve (C5), which enters the thorax to join the phrenic nerve.

·         Thoracoacromial artery branches"CAlifornia Police Department": Clavicular Acromial Pectoral Deltoid

·         Anterior forearm muscles: superficial groupThere are five, like five digits of your hand. Place your thumb into your palm, then lay that hand palm down on your other arm, as shown in diagram. Your 4 fingers now show distribution: spells PFPF [pass/fail, pass/fail]: Pronator teres Flexor carpi radialis Palmaris longus Flexor carpi ulnaris Your thumb below your 4 fingers shows the muscle which is deep to the other four: Flexor digitorum superficialis.  

·         Intrinsic muscles of hand (palmar surface) "A OF A OF A":
· Thenar, lateral to medial:
Abductor pollicis longus
Opponens pollicis
Flexor pollicis brevis
Adductor pollicis.
· Hypothenar, lateral to medial:
Opponens digiti minimi
Flexor digiti minimi
Abductor digiti minimi

Oppose, Abduct, and Flex (OAF) same kind of action.

·         No palmar interosseous muscle is attached to the middle digit.

·         The opponens pollicis inserts on the first metacarpal. All other intrinsic muscles of the thumb, including the abductor pollicis brevis, the flexor pollicis brevis, and the adductor pollicis muscles, insert on the proximal phalanges.

·         The ulnar bursa, or common synovial flexor sheath, contains the tendons of both the flexor digitorum superficialis and profundus muscles. The radial bursa envelops the tendon of the flexor pollicis longus. The tendons of the flexor carpi ulnaris and the palmaris longus are not contained in the ulnar bursa.

·         The posterior humeral circumflex artery anastomoses with an ascending branch of the profunda brachii artery, whereas the lateral thoracic and subscapular arteries do not. The superior ulnar collateral and radial recurrent arteries arise inferior to the origin of the profunda brachii artery.

·         The anterior interosseous nerve is a branch of the median nerve and supplies the flexor pollicis longus, half of the flexor digitorum profundus, and the pronator quadratus. The median nerve supplies the pronator teres, flexor digitorum superficialis, palmaris longus, and flexor carpi radialis muscles. A muscular branch (the recurrent branch) of the median nerve innervates the thenar muscles.

·         The little finger has no attachment for the dorsal interosseous muscle because it has its own abductor.

·         The subscapularis muscle inserts on the lesser tubercle of the humerus. The supraspinatus, infraspinatus, and teres minor muscles insert on the greater tubercle of the humerus. The coracohumeral ligament attaches to the greater tubercle.

·         The ulnar nerve innervates the adductor pollicis muscle. The radial nerve innervates the abductor pollicis longus and extensor pollicis brevis muscles, whereas the median nerve innervates the abductor pollicis brevis and opponens pollicis muscles.

·         The intercostobrachial nerve arises from the lateral cutaneous branch of the second intercostal nerve and pierces the intercostal and serratus anterior muscles. It may communicate with the medial brachial cutaneous nerve, and it supplies skin on the medial side of the arm. It contains no skeletal motor fibers but does contain sympathetic postganglionic fibers, which supply sweat glands.

·         The upper and lower subscapular nerves innervate the subscapularis muscle, which is the only muscle of the rotator cuff group that medially rotates the arm. The lower subscapular nerve also innervates the teres major muscle, which is not part of the rotator cuff group. The suprascapular nerve innervates the supraspinatus and infraspinatus muscles that abduct and laterally rotate the arm, respectively. The teres minor muscle, innervated by the axillary nerve, also laterally rotates the arm. The thoracodorsal nerve, originating from the posterior cord between the upper and lower subscapular nerves, innervates the latissimus dorsi muscle.

·         The flexor pollicis brevis has two heads and there is a sesamoid bone associated with each of the tendons of these heads. Sesamoid bones are isolated islands of bone that may occur in tendons passing over joints. The patella is the classic example. The adductor pollicis also has two heads (transverse and oblique), but they are not associated with sesamoid bones.

·         The deep radial nerve passes between the deep and superficial layers of the supinator muscle and lies on a bare area of the radius where it may be compressed by action of the supinator or damaged by a fracture of the radius.

·         Clavicle fracture is relatively common––brachial plexus is protected from injury by subclavius muscle.

·         Pronator Syndrome: In the proximal forearm, the median nerve may be compressed at the fibrous arch between the two heads of the FDS, the two heads of the pronator teres, the lacertus fibrosis (bicipital aponeurosis at the elbow), and the ligament of Struthers. Compression at any or all of these sites is loosely grouped under the pronator syndrome. The symptoms produced are similar to those of carpal tunnel, although nocturnal symptoms are uncommon. The palm may also feel numb because the palmar cutaneous branch is involved, but is specifically spared in carpal tunnel syndrome because that nerve branch passes superficial to the flexor retinaculum and arises proximal to the retinaculum. Symptoms may be reproduced or worsened by attempting pronation against resistance and by resisted flexion of the middle finger. However, it may be difficult to precisely locate the compressive cause in the pronator syndrome, and surgical decompression often involves release of all four potential sites of compression.