BIOLOGY 173 Lecture Notes - Lecture 33: Shoulder Girdle, Biceps, Carpal Tunnel
29 Nov 2016
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Document Summary
Major branches of the spinal nerve plexuses and their distribution. Cervical: origin c1-c5, distribution skin and muscles of the neck and chest; thoracic cavity, major branch. Brachial: origin c5-t1, distribution pectoral girdle and upper limb, major branches. Musculocutaneous flexor of arm (biceps brachii, brachialis) Median flexors of the forearm and fingers (skin of anterior lateral hand) Radial extensors of the arm (posterior lateral triceps) Ulnar anterior forearm and medial hand. Median, radial, and ulnar pass through the carpal tunnel and supply hand. Lumbar: origin t12-s4, distribution pelvic girdle and lower limbs (legs, major branch. Sacral: origin l4-s4, distribution pelvis girdle and lower limbs, major branches. Sciatic nerve (leg and foot, supplies hamstrings) Pudendal supplies perineum (between external genitalia and anus) (this is numbed before an episiotomy) Dermatomes: skin segment supplied by a spinal nerve, used to locate spinal nerve dysfunction, dermatome chart - indicates where each spinal nerve supplies on the skin.
