Lab 6: Forearm & Hand Flashcards
Tenosynovitis
Inflamed synovial sheath
Carpal Tunnel arches
Formed by two archs of wrist bone:
(proximal arch) scaphoid and pisiform
(distal arch) trapezium and hook of Hamate
Muscles & Nerve traversing the Carpal Tunnel
Flexor digitorum superficialis, flexor digitorum profundus, flexor pollicis longus. Median nerve
Flexor nerves & muscles that do NOT pass through Carpal Tunnel
Flexor carpi ulnaris, palmaris longus, and the ulnar nerve do not pass through the carpal tunnel
Carpal Tunnel Syndrome
Relatively common condition characterized by pain a/o parathesia on palmar surface of hand. It affects the lateral 3.5 digits. There is a loss of strength and atrophy of thenar muscles and precise thumb movements
Cubital Tunnel Syndrome
Ulnar nerve becomes entrapped between the humeral and ulnar heads of the flexor carpi ulnaris (CUBITAL TUNNEL). Symptoms: weakened wrist flexion, weakened grip and tingling. Affects medial 1.5 fingers (1/2 of 4th digit, 5th digit)
Cause of Compartment Syndrome/Volkmann’s ischemic contracture
Loss of arterial supply to flexor compartment of forearm
Guyon’s Canal
Found on palmar surface of hand where ulnar nerve traverses through, bound by the pisiform, hook of Hamate and flexor retinaculum.
Guyon’s Canal Syndrome
Entrapment of the ulnar nerve as it passes through Guyon’s Canal. Symptoms: numbness, pins & needles in 5th and 1/2 of 4th digit, impaired motor function.
Superficial posterior forearm muscles (6)
(lateral to medial) brachioradialis extensor carpi radialis longus extensor carpi radialis brevis extensor digitorum extensor digiti minimi extensor carpi ulnaris
Deep/Intrinsic Posterior Forearm muscles (6)
Aconeus
Supinator
(Snuff box): abductor pollicis longus, extensor pollicis brevis, extensor pollicis longus
Extensor indicis
Superficial Anterior (Palmar) Forearm muscles (4)
PFPF: pronator teres, flexor carpi radialis, palmaris longus, flexor carpi ulnaris
Deep Anterior (Palmar) Forearm muscles (4)
Flexor digitorum superficialis
Flexor digitorum profundus
Flexor pollicis longus
Pronator quadratus
All (except 2) anterior forearm muscles are innervated by which nerve? Which 2 muscles are the exception and which nerve are they innervated by?
Median nerve. 2 exceptions are the flexor digitorum profundus (medial 1/2) and flexor carpi ulnaris. These two are innervated by the ulnar nerve
What action does the Supinator muscle perform? Which anterior muscle performs the opposite action?
The supinator supinates the hand. Pronator teres does the opposite (pronates hand)
What is tennis elbow?
Aka lateral epicondylitis, it is caused by inflammation of the extensor carpi radialis brevis muscle from repeated (and forceful) wrist extension
Anterior Interosseous Syndrome
Entrapment of the anterior interosseus nerve. Symptoms: weakened pronation (pronator quadratus) and inability to flex DIP joints of 2nd, 3rd digits (flexor digitorum profundus) and joint of thumb (flexor pollicis longus)
Proximal Carpal Bones
(lateral to medial) scaphoid, lunate, triquetrum, pisiform
Distal Carpal Bones
(lateral to medial) trapezium, trapezoid, capitate, hamate
Hand compartments
5 compartments: Central, interosseous, hypothenar, thenar and adductor
Central hand compartment
Made up of the lumbricals, flexor tendons and the palmar arch
Interosseous hand compartment
Palmar interossei (3-4), deep branch of ulnar nerve, dorsal interossei (4)
Hypothenar hand compartment
Abductor digiti minimi, flexor digiti minimi, opponens digiti minimi, deep branch of ulnar nerve
de Quervain’s Syndrome
Inflammation of the tendons connecting the abductor pollis longus and extensor pollicis brevis (2/3 snuff box extensors) due to repetitive movements. Symptoms: tenderness, lateral wrist pain
