The Forearm/Wrist/Hand Flashcards
Which three muscles are responsible for thumb extension?
EPL
EPB
APL
Which two muscles are responsible for thumb flexion?
FPL
FPB
Which two muscles are responsible for thumb abduction?
AbPL
AbPB
Which two muscles are responsible for thumb adduction?
Ad P
1st dorsal interosseous
Which muscles compose the thenar eminence of the hand?
OpP
AbPB
FPB
AdP
Which muscles compose the hypothenar eminence of the hand?
AbDM
FDMB
Opponens digiti
Which muscles of the hand does the median nerve innervate?
LLOAF
First two lateral lumbricals
Opponens Pollicis
AbPB
FPB
What is the sensory distribution of the median nerve in the hand?
Lateral 3.5 fingers palmar aspect
Tips of 3.5 fingers dorsal aspect
Which muscles of the hand does the ulnar nerve innervate?
All intrinsic muscles (except LLOAF)
What is the sensory distribution of the ulnar nerve in the hand?
Palmar and dorsal aspects of 1.5 medial digits
Describe the key landmarks of the anatomical snuffbox.
Anterior boundary: Tendons of APL and EPB
Posterior boundary: Tendon of EPL
Floor: Radial artery, scaphoid, trapezium
Which muscles are involved in wrist flexion?
FCR
FCU
Assisted by: flexors of fingers and thumb, palmaris longus, APL
Which muscles are involved in wrist extension?
ECRL
ECRB
ECU
Assisted by: extensors of fingers and thumb
Which muscles are involved in wrist abduction?
APL
FCR
ECRL
ECRB
Which muscles are involved in wrist adduction?
ECU
FCU
What are the contents of the carpal tunnel?
FDP (x4 tendons)
FDS (x4 tendons)
FPL (x1 tendon)
Median nerve
What is mallet finger and how does it occur?
DIP joint forced into extreme flexion (hyperflexion) - can occur from either extensor tendon rupture at base of distal phalanx (no bony involvement) or avulsion injury
What is involved in the management of mallet finger? (2)
- Closed injuries treated with immobilisation splint with DIP joint in extension or hyperextension FULL TIME for 8 weeks, can be graded to night splinting if appropriate thereafter. Important to keep finger in extension in between/during splint changes, and watch out for skin breakdown.
- Surgery reserved for severe injury (e.g. volar subluxation of distal phalanx, injuries failing conservative management etc.)
What is trigger finger and what can it be caused by? (4)
aka stenosing tenosynovitis
Inflammation of flexor tendon sheath of finger/thumb causing pain and swelling to occur proximally at MCP joint (+/- nodule formation) and prevents smooth gliding under A1 pulley = locking of thumb or finger in flexion primarily
Aetiology: idiopathic or assoc. w/ RA, diabetes, hypothyroidism and gout
How is trigger finger diagnosed?
Primarily clinical diagnosis
How is trigger finger managed? (2)
- reduce swelling and inflammation by immobilisation for 4-6 weeks (+/- glucocorticoid injection if refractory) OR local glucocorticoid injection straight up if locking is severe
- avoid gripping, grasping etc.
- panadol and ice for pain
- on resolution of acute symptoms, gentle stretching exercises (extension)
- Surgical release of A1 pulley when locking and tenosynovitis persist despite two consecutive local glucocorticoid injection
What is carpal tunnel syndrome?
Median nerve compression at the level of the flexor retinaculum
What is the aetiology of carpal tunnel syndrome
Myxoedema Oedema Diabetes Idiopathic Acromegaly Neoplasm Trauma Rheumatoid arthritis Amyloidosis Pregnancy
List 6 clinical features of carpal tunnel syndrome
- Sensory loss in median nerve distribution i.e. radial 3.5 digits
- Classically, patient awakened at night with numb/painful hand, relieved by shaking, dangling, rubbing
- Discriminative touch often lost first, with decreased light touch and 2-point discrimination
- Advanced cases: thenar wasting, weakness
- +/- Tinel’s sign (tingling sensation on percussion of nerve)
- +/- Phalen’s sign (wrist flexion induces symptoms)