Short Ch. 2 Essential Nervous System

the first seven cervical nerves (C1-C7) exit _____ their respective vertebrae

above

C8-L5 exit _______ their corresponding vertbrae

below

motor axons are located on the ______ aspect of the spinal cord

ventral

sensory axons are located on the ____ aspect of the spinal cord

dorsal

are dorsal nerve roots motor or sensory?

sensory

are ventral nerve roots sensory or motor?

motor

dorsal and ventral nerve roots then converge, contributing both motor and sensory axons, into

dorsal rami and ventral rami

dorsal rami innervate the

skin and muscles of the back

ventral rami innervate the

ventral body wall and all parts of the limbs

dermatome

area of skin supplied by an individual spinal nerve

brachial plexus

supplies innervation to the upper extremity through five primary terminal branches: axillary, musculocutaneous, median, radial, and ulnar

brachial plexus begins with the ventral rami of _____ spinal nerve roots

C5-T1

Axillary nerve components

C5, C6

musculocutaneous nerve components

C5, C6, C7

associated movements of the musculocutaneous nerve

FOREARM FLEXION, FOREARM SUPINATION, arm adduction

Clinical Associations musculocutaneous nerve

entrapment in coracobrachialis

musculocutaneous nerve dermatome

lateral antebrachial cutaneous nerve (terminal part of musculocutaneous nerve)

axillary nerve dermatome

superior lateral brachial cutaneous nerve

associated movements of axillary nerve

ARM ABDUCTION, ARM FLEXION, arm extension, arm medial rotation, arm lateral rotation

clinical associations axillary nerve

shoulder dislocation

broken arm (neck of humerus)

entrapment in quadrangular space

radial nerve components

C5-T1

ulnar nerve components

C7 (may vary), C8, T1

median nerve components

C5-T1

median nerve innervates

muscles that contribute to forearm pronation, finger flexion, and thumb motion

radial nerve components

C5-T1 (may vary)

radial nerve associated movements

FOREARM EXTENSION, WRIST EXTENSION, DIGIT EXTENSION, SUPINATION, wrist adduction, wrist abduction, forearm flexion

radial nerve clinical associations

wrist drop, tennis elbow, broken arm (humerus shaft), entrapment in supinator

radial nerve dermatome

median nerve associated movements

FOREARM PRONATION, POLLEX MOVEMENTS DIGIT FLEXION (#2-3), DIGIT FLEXION (#4-5), wrist flexion, wrist abduction

median nerve clinical associations

carpal tunnel syndrome (CTS), ape hand, benediction sign, entrapment in pronator teres

median nerve dermatome

ulnar nerve associated movements

DIGIT ADDUCTION, DIGIT ABDUCTION, DIGIT #5 MOVEMENTS, wrist flexion, wrist adduction, digit flexion (#4-5)

ulnar nerve clinical associations

clawhand deformity, cubital tunnel syndrome, bike rider’s syndrome, Guyon’s canal syndrome

ulnar nerve dermatome

proximal median nerve lesions (above AI nerve origin)

hand of benediction (Pope’s Blessing) when the patient tries to make a fist

distal median nerve lesion (below AI nerve origin)

Median claw when the patient tries to extend fingers

wrist drop

radial nerve injury

claw hand

ulnar nerve injury

hand of benediction

median nerve injury

ventral nerve roots

motor only

dorsal nerve roots

sensory only

ventral rami

innervate ventral body wall and all limb parts; mixed

dorsal rami

innervate skin and muscles of back; mixed