Neurology Edited by Professor Emeritus Desire' Dubounet, IMUNE

Brachial plexus: spinal root supply (C4-T1) and peripheraldistributionMain features of brachial plexus lesionsUpper plexus lesion (Erb - Duchenne); roots C5-C6Paresis of shoulder abduction and external rotation and of elbow flexion. Bicepsand superior jerks lost. Sensation lost from shoulder tip down to radial side offorearm.Lower plexus lesion (Dejerine - Klumpke); roots C8-T1Paresis of finger flexion and small hand muscles. Finger jerk absentSensory loss ulnar border of hand and forearm. Possible associated Horner's syndrome.Middle plexus lesion; root C7 (uncommon, usually part of upper plexus lesion)Paresis of arm, hand and finger extension. Triceps jerk absentSensory loss digits 2 and 3, extending strip up hand and forearm.Main features of brachial plexus cord lesionsPosterior cord: axillary and radial nervesParesis of shoulder abduction, arm, hand and finger extensionSensory disturbance lateral border of arm and forearm.Lateral cord: musculocutaneous and lateral root of median nerveParesis of elbow flexion, pronation, wrist and finger flexionSensory disturbance digits 1 to 3, radial border of forearm.Medial cord: ulnar and medial root of median nerve, medial cutaneous nerves of arm andforearmParesis of thenar muscles, finger adduction and abduction, ulnar flexion of wrist and fingersSensory disturbance in ulnar border of hand.Common causes of peripheral nerve lesionsCauses of median nerve palsyPalsy including pronator teresSite of lesion: medial aspect of arm'Lovers palsy' (nocturnal pressure), trauma, surgery, supracondylar process