HTHSCI 2F03 Lecture Notes - Lecture 14: Abductor Pollicis Brevis Muscle, Posterior Interosseous Nerve, Brachial Artery
26 Dec 2020
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Document Summary
Roots leave vertebral column between scalenus anterior and medius. Divisions occur under the clavicle, medial to coracoid process. Plexus has intimate relationship c subclavian and brachial arteries. Median n. is formed anterior to brachial artery. Direct: e. g. shoulder girdle #, penetrating or iatrogenic injury. Leffert classification: open, closed, supraclavicular, infraclavicular, radiation-induced, obstetric, upper, lower, mixed. Loss of extension of cmc joints (finger drop) Site: # shaft of humerus where n. is in radial groove. Loss of sensation to dorsum of thumb root (snuff box) Site: axilla e. g. crutches or sat night palsy. Ulnar paradox: lesion at elbow has less clawing as. Fdp is paralysed, decreasing flexion of 4th/5th digits. Froment"s sign: flexion of thumb ipj when trying to hold onto paper held between thumb and finger. Can"t flex index finger ipjs (e. g. on clasping hands) Carpal tunnel formed by flexor retinaculum and carpal bones. Median n. supplies lloaf (abductor pollicis brevis)
