Wrist Hand Anatomy

Question 1

Wrist Flexion (musc, inn.)

Answer 1

FCR: C6-7, upper and middle trunk, lateral cord, median n.

FCU: C8-T1, lower trunk, medial cord, ulnar n.

to lesser degree:
FDS
FDP
FPL
PL

Question 2

Wrist extension (musc, inn.)

Answer 2

ECRL, ECRB: C6-7, upper and middle trunk, posterior cord, radial n.

ECU: C7-8, middle and lower trunk, posterior cord, radial n., PIN

lesser degree:
ED
EIP
EPL
EDM

Question 3

Ulnar deviation (musc, inn.)

Answer 3

FCU: C8-T1, lower trunk, medial cord, ulnar n.

ECU: C7-8, middle and lower trunk, posterior cord, radial n., PIN

Question 4

Radial deviation (musc, inn.)

Answer 4

FCR: C6-7, upper and middle trunk, lateral cord, median n.

ECRL, ECRB: C6-7, upper and middle trunk, posterior cord, radial n.

Question 5

Carpal Tunnel (volar side of wrist)

Answer 5

4 FDS tendons

4 FDP tendons

FPL tendon

median n.

all under flexor retinaculum

bordered by scaphoid (radially) and pisiform (ulnarly)

Question 6

Dorsal side of wrist

Answer 6

6 compartments

1st: APL, EPB (DeQuevain Tenosynovitis)
2nd: ECRL, ECRB
3rd: EPL (Drummer’s wrist)
4th: ED, EIP (4 fingers, 4th compartment)
5th: EDM (5th finger, 5th compartment; Vaughn Jackson syndrome)
6th: ECU (common source snapping in wrist)

Question 7

Colles v Smith fracture

Answer 7

types of distal radius fractures

Colles: distal radius fragment is dorsally displaced (CD)

Smith: distal radius fragment is volarly displaced (Sweater Vest)

Question 8

scaphoid fracture

Answer 8

pain in anatomic snuffbox

most common at scaphoid waist

immobilize w thumb spica case, repeat XR in 2 wks if initial XR negative but still suspect scaphoid fx

proximal ⅓ of scaphoid has highest risk of AVN → consider surgery (also if fx is displaced)

Question 9

Kienbock disease

Answer 9

idiopathic AVN of lunate

Px: pain over dorsal wrist, ulnar to snuffbox

Dx: PE (pain on palpation), XR

Question 10

hamate fracture

Answer 10

Px: pain worse w swinging bat or golf club

Tx: short arm cast (non displaced)

Question 11

½ LOAF muscles

Answer 11

median innervated hand muscles:

½ lumbricals (thumb sided)

opponens pollicus

abductor pollicus brevis

flexor pollicus brevis

Question 12

finger abduction v adduction (musc, inn.)

Answer 12

ABd: dorsal interossei (DAB); ulnar n.

ADd: palmar interossei (PAD); ulnar n.

3 PADs, 4 DABs

B before D, D before P (aBduct, aDduct; DAB, PAD)

Question 13

Finger flexion (musc, inn)

Answer 13

PIP flexion: FDS; C7-8, middle and lower trunk, medial and lateral cord, median n.

DIP flexion:
FDP digits 2 and 3; C7-T1, medial cord, median n. and AIN
FDP digits 4 and 5; C7-T1, medial cord, ulnar n.

Question 14

thumb flexion (musc, inn)

Answer 14

FPL: C7-T1, middle and lower trunk, medial and lateral cord, median n. and AIN

FPB: C8-T1, lower trunk, medial cord, median AND ulnar n

Question 15

finger extension (musc, inn)

Answer 15

digits 2-5:
EDC: C7-8, middle and lower trunk, posterior cord, radial n. and PIN
attaches to extensor expansion

digit 2:
EIP: C7-8, middle and lower trunk, posterior cord, radial n. and PIN

thumb extension: EPL

digit 5: ADM

Question 16

Boxer’s fracture

Answer 16

metacarpal neck/shaft fracture

5th metacarpal fracture, usually

after punching something very hard

Question 17

Skier’s thumb

Answer 17

1st UCL injury of the MCP d/t excessive radial deviation → UCL strain

test for RCL/UCL injuries by applying lateral force

Question 18

Stener’s lesion

Answer 18

trapping of thumb adductor aponeurosis in the MCP joint d/t severe UCL tear → ortho referral +/- surgery

Question 19

MCP/PIP/DIP collateral ligament injury

Answer 19

d/t excessive varus of valgus deviation

Tx: extension splint or buddy tape

Question 20

Dupuytren contracture

Answer 20

palmar fascia thickens into fibrous cords → painless swelling and flexion contracture (usually 4th digit)

RFs: older male, seizures/DM/acloholism

Question 21

Trigger finger

Answer 21

stenosing tenosynovitis at A1 (MCP) pully of a finger flexor → nodule forms → prevents flexor tendon from gliding through smoothly

finger tends to snap/catch when flexing/extending

Question 22

Jersey finger

Answer 22

REQUIRES SURGERY

FDS or FDP tendon avulsion d/t sudden hyperextension (e.g., getting caught in a player’s jersey) → pain/swelling in finger/palm → inability to flex PIP or DIP

Question 23

Mallet finger

Answer 23

sudden DIP flexion → extensor tendon rupture +/- avulsion fracture (bony fragment) → painful/swollen distal finger → inability to extend DIP

Tx: DIP extension splint to allow tendon to heal for several weeks
surgery if big avulsed bone fragment