Flashcards in The Forearm/Wrist/Hand Deck (45):
Which three muscles are responsible for thumb extension?
Which two muscles are responsible for thumb flexion?
Which two muscles are responsible for thumb abduction?
Which two muscles are responsible for thumb adduction?
1st dorsal interosseous
Which muscles compose the thenar eminence of the hand?
Which muscles compose the hypothenar eminence of the hand?
Which muscles of the hand does the median nerve innervate?
First two lateral lumbricals
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?
Assisted by: flexors of fingers and thumb, palmaris longus, APL
Which muscles are involved in wrist extension?
Assisted by: extensors of fingers and thumb
Which muscles are involved in wrist abduction?
Which muscles are involved in wrist adduction?
What are the contents of the carpal tunnel?
FDP (x4 tendons)
FDS (x4 tendons)
FPL (x1 tendon)
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)
1. 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.
2. 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)
2. 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
List 6 clinical features of carpal tunnel syndrome
1. Sensory loss in median nerve distribution i.e. radial 3.5 digits
2. Classically, patient awakened at night with numb/painful hand, relieved by shaking, dangling, rubbing
3. Discriminative touch often lost first, with decreased light touch and 2-point discrimination
4. Advanced cases: thenar wasting, weakness
5. +/- Tinel's sign (tingling sensation on percussion of nerve)
6. +/- Phalen's sign (wrist flexion induces symptoms)
How is carpal tunnel diagnosed?
NCV and EMG may confirm, but do not exclude, the diagnosis
How is carpal tunnel syndrome managed? (3)
1. Wrist splinting in neutral position - usually at night but can be worn continuously esp. when repetitive wrist motion required
2. Medical: NSAIDs, local corticosteroids, oral corticosteroids
3. Surgical decompression - indicate if symptoms are intolerable and/or unresponsive to conservative measures
What is the most common carpal bone injured?
Describe the type of injury seen in a scaphoid fracture.
Most commonly a transverse fracture through the waist of scaphoid, but can be distal or proximal fracture also
A larger percentage of proximal fractures result in non-union or AVN due to distribution of blood supply
Which clinical feature is most sensitive for scaphoid injury?
Tenderness over anatomical snuffbox
How is a suspected scaphoid fracture investigated?
1. X-rays: AP, lateral ,scaphoid view *wrist extension and ulnar deviation)
2. If X-ray negative but clinical features present, splint or plaster should be applied For two weeks
3. After two weeks, a second X-ray is taken. If still no abnormalities, MRI or CT scan.
How is an undisplaced scaphoid fracture managed? (3)
1. No reduction required
2. Cast: upper foreatm to just short of MCPs of fingers, incorporation proximal phalanx of thumb ('holding glass' position) for 8 weeks
3. After 8 weeks,remove plaster and examine wrist clinically and radiologically - if all good, wrist left free
How is a displaced scaphoid fracture managed?
ORIF (with compression screw)
List 3 complications of scaphoid fractures.
1. AVN due to distal to proximal supply
3. OA secondary to AVN or non-union
What is a nightstick fracture and how does it occur?
Isolated fracture of ulna without dislocation of radial head - from direct blow to forearm (e.g. holding arm up to protect face)
How is a nightstick fracture managed? (2)
1. Non-displaced - below elbow cast (x10 d) followed by forearm brace (~8 weeks)
2. Displaced - ORIF if more than 50% displaced
What is a Galeazzi fracture and how does it occur?
Fracture of the distal radial shaft with disruption of the distal radio-ulnar joint and associated ulnar dislocation.
FOOSH with some rotational force
What is the piano-key sign?
Seen in a Galeazzi fracture - unstable ulna can be ballotted by holding patient's forearm pronated and pushing sharply on prominent head of ulna
How is a Galeazzi fracture managed? (3)
1. ORIF of radius
2. If DRUJ is stable and reducible, splint for 48h with early ROM encouraged
3. If DRUJ is unstable, ORIF or percutaneous pinning with long arm cast in supination x 6 weeks
What is a Colles' fracture and in whom does it usually occur?
Transverse distal radius fracture with dorsal displacement +/- ulnar styloid fracture
Most common fracture in those >40 years especially women due to post-menopausal osteoporosis - mechanism = FOOSH
What is the typical clinical feature seen in a Colles' fracture?
'Dinner fork deformity' - prominence of back of wrist and depression in front
How is an undisplaced Colles' fracture managed? (3)
1. Dorsal splint for a few days until swelling resolves, then cast is completed
2. X-rays at 2 weeks - surgery if fracture has slipped
3. If not, cast removed at 4 weeks to allow mobilisation
How is a displaced Colles' fracture managed? (3)
1.Closed reduction under anaesthesia (Haematoma, Bier's or axillary block)
2. Position checked by X-ray and dorsal plaster slab applied
3. X-rays retaken at 7-10 days - if re-displaced - re-manipulation/internal fixation in patients with high functional demands
- in older people - modest degrees of displacement accepted
What is a Smith's fracture and how does it occur?
Volar displacement of the distal radius (i.e. distal fragment displaced anteriorly) aka reverse Colles' fracture
Can occur after fall onto the back of the flexed hand causing 'garden spade' deformity
How is a Smith's fracture managed?
Usually unstable and needs ORIF - closed reduction under block then long-arm cast in supination x 6 weeks