Functional Anatomy of the Hand

Question 1

What is the key nomenclature that is different in the hand to the rest of the body?

Answer 1

Radial + ulnar = lateral + medial

Question 2

Describe the blood supply to the hand

Answer 2

Radial and ulnar arteries connected by superficial arch (superficial to flexor tendons) and the deep palmar arch

Question 3

What is the allens test?

Answer 3

Test for occlusion of radial or ulnar arteries: patient makes a tight fist so as to express the blood from the skin of the palm and fingers, examiner compresses radial or ulnar artery. Failure of blood to return indicates obstruction of the blood flow in the artery that has not been compressed

Question 4

Describe the cutaneous distribution of the ulnar nerve

Answer 4

runs on ulnar side, doesn’t go through carpal tunnel, supplies little finger and ½ ring finger and small muscles of the hand

Question 5

Describe the cutaneous distribution of the median nerve

Answer 5

through carpal tunnel, to middle on hand, supplies thumb, index, middle, ½ of ring finger

Question 6

Describe the cutaneous distribution of the radial nerve

Answer 6

doesn’t supply any muscles in the hand, but does in the forearm that allow finger/wrist extension, sensation of thumb index middle distal surface.

Question 7

Describe the boundaries of the carpal tunnel

Answer 7

carpal bones posterior and the flexor retinaculum anterior

Question 8

Describe the contents of the carpal tunnel

Answer 8

median nerve, 9 tendons: 1 of flexor pollicis longus, 4 of flexor digitorum profundus, 4 of flexor digitorum superficialis

Question 9

How many flexors tendons are there in each digit?

Answer 9

2 per finger, 1 in the thumb

Question 10

What is an extrinsic vs intrinsic hand muscle?

Answer 10

Muscles that run from the forearm = extrinsic muscles muscles originating in the hand = intrinsic muscles

Question 11

How are the flexor tendons arranged in the fingers?

Answer 11

flexor digitorum superficialis splits into 2 attaches intermediate phalanx from which come flexor digitorum profundus attaches distal phalanx – held tightly to bone by sheath to increase range of motion

Question 12

Describe how extensor tendons are arranged

Answer 12

tendons that dorsiflex wrist are close to bone, finger extensors are superficial

Question 13

What are lumbricals?

Answer 13

muscles arising from flexor tendons, which bridge the flexor tendons to the extensor tendons = allow MCP joint to flex and PIP to extend

Question 14

Name the carpal bones

Answer 14

Scaphoid, Lunate, Triquetrum, Pisiform, Trapezium, Trapezoid, Capitate, Hamate

Question 15

Name the bones of the hand

Answer 15

Carpals, metacarpals, phalanx

Question 16

Where is the thenar and hypothenar eminence located?

Answer 16

T = below thumb, H = below little finger