Rutgers Functional Human Anatomy Lec 7 (Nerve Plexuses)

4 nerve plexuses

cervical, brachial, lumbar, sacral

cervical plexus

C1-C4

- provide sensory input from head, neck, shoulder

- nerve root

- 2 cranial nerve 11 & 12

- 11 (accessory)

- 12 (hypoglossal nerve)

brachial plexus

C5-T1 (most complicated)

- spinal cord > 6 roots > 3 trunks > 2 division > 3 cords > nerves (read the damn cadaver notes)

- nerves come off of cords with specific names and functions

roots (C5-T1)

trunks (superior, middle, inferior)

division (anterior & posterior)

cords (posterior, lateral, medial)

trunks of brachial plexus

superior C5-C6

middle C7

inferior C8&T1

Lateral cord of brachial plexus

superior division of (superior and middle trunk)

Medial cord of brachial plexus

anterior division of inferior trunk

posterior cord of brachial plexus

takes all trunks

lumbar plexus

T12-L4

- provide innervation to some abdominal muscles

- innervate to thigh

- sensory to regions of the thigh, genitalia, leg, foot

sacral plexus

L4-S4

- provide muscular innervation to glutes, leg muscles

- sensory to posterior thigh & leg

- motor of sphincter muscles

- sensory to genitalia

sciatic nerve (sacral plexus)

- biggest nerve in human body

- runs down posterior leg

- splits into tibial and common fibular nerve

Dermatomes (sacral plexus)

area of the skin that is mainly supplied by branches of a single spinal sensory nerve root

Reflex

- immediate involuntary motor response

Reflex arc

- neural "wiring" of a single reflex

- begins at a sensory receptor and ends at a peripheral effector

Contralateral

on the opposite side of the body from another structure