hand/lower extremity Flashcards
Intrinsic muscles
PAD (Palmar interossei ADduct fingers) and DAB (Dorsal interossei Abduct)
Lumbricals: radial 2 innervated by median nerve and ulnar 2 by ulnar nerve; origin FDP tendon and insertion extensor apparatus at proximal phalanx. Flex MCP and extend PIP.
colchicine
treatment for gout
methotrexate
treatment for rheumatoid arthritis
Reverse sural artery flap
Based on peroneal artery system. Includes the sural nerve, lesser saphenous vein and superficial sural artery. Perforators 5cm proximal to lateral malleolus.
Medial sural artery perforator flap
based on popliteal system with perforators through the medial gastrocnemius muscle. The flap is based on the posterior calf and the pivot point is 5cm proximal to the lateral malleolus.
Medial plantar artery flap
terminal branch of posterior tibial artery between the abductor hallucis and flexor digitorum brevis. Can be distally based through retrograde flow through lateral plantar artery. Innervation from medial plantar nerve from tibial nerve.
Enchondroma
most common benign bone tumor in the hand, usually proximal phalanx, middle phalanx or metacarpal. Benign but locally destructive. Well-circumscribed, radiolucent either expansile or lytic with popcorn stippled calcification. May be observed if small and asymptomatic, treatment is curettage with or without bone grafting. If pathologic fracture then treat fracture first then curettage and bone graft. Multiple in Ollier disease (with skeletal dysplasia) and Mafucci syndrome (with hemangiomas) and increased risk of malignant transformation.
Osteoid osteoma
benign tumor from osteoblasts. Focal pain relieved by NSAIDS. CT scan shows nidus (radiolucent central area of high attenuation representing mineralized osteoid)
Osteosarcoma
most common malignant bone tumor. Childhood and proximal humerus. Most likely to metastasize to the lung. Sunburst pattern with periosteal elevation at Codman’s triangle. Mesenchymal origin with spindle cells on histology. Treat with wide excision or amputation and neoadjuvant chemotherapy.
Compression median nerve
a. Course
i. Medial and lateral cord
ii. Upper arm: between brachialis and intermuscular septum with brachial artery
iii. Forearm: between FDS and FDP then under PL into carpal tunnel
iv. palmar cutaneous branch 5cm proximal to carpal tunnel
b. Ligament of struthers (prontor teres at supracondular rim)
c. Crosses antecubital fossa under bicipital aponeurosis (lacertus fibrosis)
d. Pronator syndrome: proximal forearm – paresthesias in palm (palmar cutaneous branch comes off before carpal tunnel), and thumb to MF, weakness in FPL, FDP to IF
e. Anterior interosseous syndrome – motor only compression in proximal forearm, supplies FPL, FDP to index finger and PQ
f. Carpal tunnel syndrome
i. Motor latency >4.5 msec
ii. Sensory latency >3.5 msec
compression radial nerve
a. Course: posterior cord, enters forearm between two heads of supinator muscles then lies between brachioradialis and ECRL and ECRB.
b. Four areas of compression at the elbow
i. Proximal to the radial tunnel (fibrous bands anterior to radiocapitellar joint)
ii. Leash of Henry (radial recurrent artery)
iii. Extensor carpi radialis brevis originating tendon
iv. Arcade of Frohse (between the medial and lateral heads of the supinator)
c. Radial tunnel syndrome – middle finger test: pain over ECRB during forceful extension of middle finger and elbow
d. Posterior interosseous syndrome – motor only, extensor muscles in the forearm (all except ECRL)
e. Note that lateral antebrachial cutaneous nerve (continuation of musculocutaneous nerve) has over lapping innervation with radial with sensation to radial wrist.
f. wartenberg syn: compression of superficial radial nerve at exit from beneath brachioradialis results in pain and numbness of dorsal radial distal forearm and hand
Ulnar nerve compression
a. Course: medial cord, runds medial and posterior to brachial artery. Medial to medial triceps, posterior to medial epicondyle, between FCU heads, between FDP/FDS muscle bellies, ulnar to hook of hamate through Guyons canal
b. Motor: (FCU, FDP to ring and small, hypothenar muscles, lumbricals ring and small, interossei, AdP)
c. Guyons canal
- boarders: pisiform, hook of the hamate, volar carpal ligament, transverse carpal ligament
- type I proximal motor and sensory
- type II volar motor branch affected
- type III dorsal sensory branch affected (note dorsal/ulnar hand sensation still intact because dorsal cutaneous branch comes off proximal to Guyons canal)
d. Cubital tunnel: arcade of struthers, Osborne ligament, FCU
4. Martin-Gruber anastomosis: motor connection between median and ulnar nerves in forearm
5. Riche-Cannieu anastomosis: motor connection between median and ulnar nerves in hand
Tendon transfers for ulnar nerve injury
a. Bouvier test – if blocking MP joint hyperextention allows IP joint extension then PIP joint capsule and extensor mechanism are working
b. Thumb adduction: FDS or ECRB to adductor pollicis
c. Finger abduction (index most important): APL, ECRL, or EIP to 1st dorsarl interosseous
d. Revers clawing effect:
- donors pass along path of lumbricals volar to transverse metacarpal ligament, then to lateral band or proximal phalanx or loop around A1 or A2 pulley
- FDS (can split along Campers chiasm)
- FCR, ECRL, ECRB, BR (need tendon graft)
tendon transfers for radial nerve and PIN palsy
a. Elbow extension: deltoid, latissimus or biceps to triceps
b. Wrist extension: PT to ECRB (in PIN palsy the ECRL still functions)
c. Finger extension: FCU to EDC
d. Thumb extension: PL to EPL
tendon transfers for low median nerve palsy
a. Thumb opposition and abduction (all donor tendons insert on the APB insertion at the dorsoradial aspect of the thumb metacarpal head):
- Bunnell: FDS ring (use FCU as pulley)
- EIP (pulley around ulnar side of wrist)
- Camitz: PL
- Huber: ADM
