BIO 201 4.3 PNS Nerve Functions

how many pairs of spinal nerves are there

31

how many pairs of cervical spinal nerves

8 (C1-C8)

how many pairs of thoracic spinal nerves are there

12 (T1-T12)

how many pairs of lumbar spinal nerves

5 (L1-L5)

how many pairs of sacral spinal nerves

5 (S1-S5)

how many pairs of coccygeal spinal nerves are there

1

what are all spinal nerves

mixed nerves

what do anterior roots carry

motor axons emerging from the spinal cord

what do posterior roots carry

sensory axons to the spinal cord

After the anterior and posterior roots fuse to form the spinal nerve what does it split into

3 branches, posterior ramus, anterior ramus, and meningeal branch

what does the posterior rami do

serve the skin, joints, and musculature of the posterior trunk

what does the small meningeal branches do

reenter the vertebral canal to innervate spinal structures

what do the anterior rami do

travel anteriorly to supply the muscles of the upper and lower limbs, anterior thorax, and abdomen and part of back

what do the intercostal nerves do

innervate the intercostal muscles, abdominal muscles and skin of the chest and abdomen

what are the different plexuses

cervical, brachial, lumbar, sacral

what does the cervical plexus serve

head, neck, shoulders

whats the mnemonic for the cervical plexus

LAST-GaP

what does the lesser occipital nerve do

cutaneous sensory from skin of lateral neck and scalp posterior to auricle

What does the ansa cervicalis innervate?

omohyoid, sternohyoid, sternothyroid

what does the supraclavicular nerve innervate

skin over clavicle and shoulder

what does the transverse cervical nerve innervate

skin of anterior neck

what does the great auricular nerve innervate

cutaneous & sensory innervation of the external ear, mastoid area, & parotid salivary gland. When you follow it, it travels towards the ear's direction.

what does the phrenic nerve do

innervates the diaphragm

what keeps you alive

c3, 4, 5

How is the brachial plexus divided?

3 trunks, 2 divisions, 3 cords, 5 branches

What are the 3 trunks of the brachial plexus?

Superior (C5-C6)

Middle (C7)

Inferior (C8-T1)

what does each trunk split into

anterior and posterior divisions

what divisions form the medial cord

anterior division of inferior trunk

what divisions form the lateral cord

anterior divisions of superior and middle trunks

what divisions form the posterior cord

posterior divisions of all three trunks

what is the mnemonic for the brachial plexus nerves

MARMU

what does the musculocutaneous nerve do

Flex elbow and biceps reflex, deep to biceps brachii but superficial to brachialis, M shape

what nerve comes from the lateral cord

musculocutaneous

what does the axillary nerve do

deltoid muscle for abduction of arm

what nerve comes from the posterior cord

axillary and radial

what does the radial nerve do

extensors of arm and forearm

sensory of posterior arm and forearm and posterolateral hand

what nerves come from the lateral and medial cords

median

what does the median nerve do

it supplies most of the muscles of the forearm that flex the hand, certain intrinsic hand muscles (meaning the muscles all originate within the hand), & the skin over the anterior & lateral hand.

what nerves come from the medial cord

ulnar nerve

what does the ulnar nerve do

supplies certain muscles in the forearm that flex the hand, most of the intrinsic muscles of the hand, & the skin over the medial hand

what are the only nerves found in the forearm

radial, medial, and ulnar

what is the mnemonic for the lumbar plexus

I-I-GOLF

what does the iliohypogastric and ilioinguinal nerves do

innervation to the transversus abdominis & internal oblique muscles & sensory to the pelvic area.

what does the genitofemoral nerve do

skin around the anteromedial thigh and genitals

what does the obturator nerve do

medial thigh muscles and skin

what does the lateral femoral cutaneous nerve do

mainly sensory innervation to skin of the femoral region

what does the femoral nerve do

motor innervation to most of the anterior thigh muscles that extend the knee & sensory innervation to the skin of the anterior & medial thigh.

what does the femoral nerve become

saphenous nerve

what is the largest nerve of the lumbar plexus

femoral nerve

what is the mnemonic for the sacral plexus

SIPPS

what does the superior gluteal nerve do

supplies the gluteus medius, gluteus minimus, & tensor fascia lata muscles

what does the inferior gluteal nerve do

motor innervation to gluteus maximus

what does the pudendal nerve do

muscles of pelvic floor and sensory to genitalia

what does the posterior femoral cutaneous nerve do

skin in posterior thigh

what doe the sciatic nerve split into

tibial and common fibular

what does the tibial nerve do

Provides motor innervation to posterior muscles of thigh, posterior leg, & foot.

what does the superficial fibular nerve do

motor innervation for lateral leg

what does the deep fibular nerve do

Supplies the anterior muscles of the leg that dorsiflex the foot & the intrinsic muscles of the foot (muscles found within the feet).

what does the sural nerve do

supplies the skin of the posterior leg & foot