Wrist & Hand Flashcards
What is the look component of the wrist exam?
Skin discoloration:
- erythema (cellulitis)
- white (arterial insufficiency)
- blue/purple (venous congestion)
- black spots (melanoma)
Trophic changes e.g. increased hair growth, altered sweat production,
Swelling
Muscle atrophy:
- thenar (median nerve)
- interossei (ulnar nerve)
Deformity:
- asymmetry
- angulation
- rotation
- amputation
- absent cascade sign
How can the carpal bones be identified?
Put finger on Lister’s tubercle of radius and slide distal to find scaphoidand lunate after “cliff”
Middle finger —> wrist to find capitate (largest carpal bone)
Trapezium and trapezoid under thumb
What is the function and innervation of palmaris brevis?
Improves grip
Superficial branch of ulnar nerve (C8, T1)
What is the function and innervation of the dorsal interossei?
Abduction of index, middle, and ring fingers at MCP
Deep branch of ulnar nerve (C8, T1)
What is the function and innervation of the palmar interossei?
Adduction of tumb, index, ring, and little fingers at MCP
Deep branch of ulnar nerve (C8, T1)
What is the function and innervation of adductor pollicis?
Adducts thumb
Deep branch of ulnar nerve (C8, T1)
What is the function and innervation of the lumbricals?
Flex MCP whilst extending IP
Medial 2 = deep branch of ulnar nerve
Lateral 2 = digital branches of median nerve
What is the function and innervation of opponens pollicis?
Medial rotation of the thumb
Recurrent branch of median nerve (C8, T1)
What is the function and innervation of abductor pollicis brevis?
Abducts thumb at MCP (point thumb towards ceiling)
Recurrent branch of median nerve (C8, T1)
What is the function and innervation of flexor pollicis brevis?
Flexes thumb at MCP
Recurrent branch of median nerve (C8, T1)
What is the function and innervation of opponens digiti minimi?
Lateral rotation of fifth metacarpal
Deep branch of ulnar nerve (C8, T1)
What is the function and innervation of abductor digiti minimi?
Abducts little finger at MCP
Deep branch of ulnar nerve (C8, T1)
What is the function and innervation of flexor digiti minimi brevis?
Flexes little finger at MCP
Deep branch of ulnar nerve (C8, T1)
What are the testing areas of the dermatomes in the hand?
Median = radial side of index finger/fingertip of index finger
Ulnar = ulnar side of little finger/fingertip of little finger
Radial = radial side of dorsum/anatomical snuffbox/2st dorsal webspace
Describe the functions of the median nerve.
Sensation: volar thumb and radial 2 and a half digits and palm
Muscles:
- superficial forearm: pronator teres, flexor carpi radialis, palmaris longus
- intermediate forearm: flexor digitorum superficialis
- deep forearm (via ant. interosseous nerve): flexor pollicis longus, pronator quadratus, radial half of flexor digitorum profundus
- intrinsic hand: thenar muscles via recurrent branch, and radial two lumbricals (LOAF)
Branches: ant. interosseous nerve and palmar cutaneous nerves
What are the causes of carpal tunnel syndrome?
TRAMP
Trauma RA Acromegaly Myxodema (hypothyroidisim) Pregnancy
What is the result of a lesion at the wrist causing damage to the median nerve e.g. lacerations proximal to flexor retinaculum?
Paralysis of thenar muscles —> cannot oppose thumb
Paralysis of radial two lumbricals —> cannot flex at MCP or extend at IP of index and middle fingers
= hand of Benediction (when trying to make a fist, can only flex little and ring fingers)