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)
Describe the functions of the ulnar nerve.
Sensation: volar and dorsal ulnar one and a half digits and palm/dorsum
Muscles:
- ant. forearm: flexor carpi ulnaris, flexor digitorum profundus
- hypothenar muscles: abductor digiti minimi, flexor digiti minimi brevis, opponens digiti minimi, palmaris brevis
- intrinsic hand: ulnar two lumbricals, adductor pollicis, interossei (all except LOAF)
Branches: palmar cutaneous branch, dorsal cutaneous branch, superficial branch
What is the result of a lesion at the wrist damaging the ulnar nerve?
Loss of palmar branch and superficial branch —> sensory loss over palmar ulnar one and a half fingers
Paralysis of interossei —> fingers cannot aduct or adduct
Paralysis of ulnar two lumbricals —> cannot flex at MCP joints or extend at IP joints of ring or little fingers
Unopposed action of extensor muscles —> hyper-extension of MCP joints and hyper-flexion of IP joints
= ulnar claw (presentation at rest)
Describe the functions of the radial nerve.
Sensation: radial half of dorsum
Muscles:
- superficial foream: brachioradialis, extensor carpi radialis longus and brevis, extensor digitorum, extensor digiti minimi, extensor carpi ulnaris, anconeus
- deep forearm: supinator, abductor pollicis longus, extensor pollicis longus and brevis, extensor indicis
Branches: lower lateral cutaneous nerve of arm, posterior cutaneous nerve of arm and forearm, superficial branch of radial nerve
What is Phalen’s test?
Hold wrist in forced flexion by pressing against each other for 30s-60s
In carpal tunnel causes paraesthesia in distribution of digital branch of median nerve
What is Tinel’s test?
Tapping the flexor retinaculum elicits paraesthesia in the distribution of the digital branch of the median nerve in carpal tunnel.
How do you test for the function of flexor digitorum superficialis?
PIP flexion
Isolate by extending other three digits to fix other FDPs (one common muscle belly)
How do you test for the function of flexor digitorum profundus?
DIP flexion
Isolate by fixing FDS at same finger (four separate muscle bellies)
How do you test for ulnar nerve impairment?
Froment’s sign
Gripping piece of paper without adductor pollicis causing overcompensation by flexor pollicis longus —> pinching effect of IP joint
What is Allen’s test?
Occlude ulnar and radial arteries —> clench fist —> palm blanched
Release artery to test patency —> if palm is perfused, artery is functional
What is Beighton’s score?
Score for hypermbolity
+1 for hands flat on floor with knees straight
+1 for each thumb bent back to touch arm
+1 for each elbow bent backwards
+1 for each little finger bent back at 90 degrees
+1 for each knee bent backwards
/9
What is Colles’ fracture?
Fracture of distal one and a half cm with dorsal angulation and impaction but without involvement of the articular surface
Caused by fall on outstretched hand (pronated forearm in dorsiflexion)
What is Smith’s fracture?
Fracture of distal one and half cm of radius with ventral angulation and impaction but without involvement of the articular surface
Caused by fall onto flexed wrist or direct blow to back of wrist
What occurs as a result of central slip rupture?
PIP loss of extension and DIP hyperextension = Boutonniere deformity
What occurs as a result of volar plate rupture?
PIP hyperextension and DIP loss of flexion = swan-neck deformity
What occurs as a result of an isolated rupture of the extensor tendons to the DIP joint?
Mallet finger
What is Mannerfelt syndrome?
Osteophyte in scaphoid causes rupture of flexor pollicis longus —> passive but not active flexion of thumb
When making fist, thumb cannot be flexed
What is Vaughan–Jackson syndrome?
Extensor tendon rupture due to caput-ulna syndrome (ulna subluxation and erosion can cut overlying extensor tendons)
What is the most painful part of the finger in stenosing tenosynovitis?
A1 pulley over MCP joint (will feel nodule on palmar side)
Compare tendon rupture to dislocation in terms of the range of movement.
Tendon rupture —> passive movement corrects, therefore normal range of movement
Dislocation —> passive movement does not correct, therefore abnormal range of movement
What ligaments are present around flexor tendons of the finger?
Annular ligaments A1-A5
Cruciform ligaments: C0-C3
What are the Kanavel signs of flexor tendon infections?
- Finger held in flexion
- Fusiform swelling
- Tenderness along flexor tendon sheath
- Pain with passive extension of digit
reminder: thumb and little finger tendon sheaths continuous with wrist therefore potential to spread
What is stenosing tenosyovitis? How is it managed?
Inflammation of flexor tendon sheath caused by entrapment of flexor tendons at level of A1 pulley
- finger clicking
- pain in palm near A1 pulley
- finger becomes “locked” in flexed position
- tenderness to palpation over A1 pulley
- palpable bump under A1 pulley
Mx:
- steroid injections
- surgery: release A1 pulley
Contrast testing the abduction and anteversion of the thumb.
Abduction = in plane of palm
Anteversion = in plane perpendicular to palm
What is Kirk-Watson’s test?
Scapho-lunate instability
Grab pt wrist with thumb over scaphoid tubercle to prevent it moving vertically.
Move pts wrist from ulnar to radial deviation —> examiner feels “clunk” and pt feels pain
What is axial loading of the thumb testing for?
Increased axial loading of thumb causes pain/crepitation in OA of thumb base or scaphoid fracture.
What is Eischhoff’s/Finkelstein’s test?
de Quervain’s tenosynovitis
Close fist around thumb and ulnarly deviate wrist —> pain (tenosynovitis in abductor pollicis longus + extensor pollicis brevis tendons)
What should be examined in Dupuytren’s contracture?
Check whether cord is pre-tendon or not
Check whether contracture extends into MCP/PIP/DIP
Check whether abductor digiti minimi is involved
Check other hand
Describe degree of flexion
