Spinal Nerves Flashcards
How many pairs of nerves are there in the spine?
31 pairs- thousands of nerve fibers
What does the spinal nerves connect to?
Spinal cord
How many pairs of cervical nerves are in the spinal cord?
8 pairs C1-C8
How many pairs of thoracic nerves are in the spinal cord?
12 pairs T1-T12
How many pairs of lumbar nerves are there in the spinal cord?
5 pairs L1-L5
How many pairs of sacral nerves are there in the spinal cord?
5 pairs S1-S5
How many pairs of coccygeal nerves are there in the spinal cord in the spinal cord?
1 pair Co1
Why are there 8 pairs of cervical nerves and only 7 pairs of vertebra nerves?
Has 1 extra pair due to the 1st spinal cord comes out before the vertebra connects
Order of the nerves from top of spine to bottom
Cervical, thoracic, lumbar, sacral, coccygeal
What is the nerve plexus?
A network of nerves
What is the brachial plexus?
Formed by ventral rami of C5-C8 give rise to cords and T1
What form nerve plexuses?
Cervical, brachial, lumbar, sacral
What is the cervical plexus?
Formed by ventral rami of first four cervical nerves (C1-C4)
Important nerves that arise from the brachial plexuses are
Axillary, musculocutaneous, radial, median, ulnar nerves
What is axillary nerve?
Innervates the
deltoid and teres minor
What is musculocutaneous nerve?
Sends fibers to the biceps brachii and brachialis
What is median nerve?
Branches to most of the flexor muscles of forearm
What is ulnar nerve?
Supplies the flexor
carpi ulnaris and part of the
flexor digitorum profundus
What is radial nerve?
Innervates essentially all extensor muscles
What is lumbar plexus?
Femoral anterior; arises from L1-L4
What is the sacral plexus?
Femoral posterior; arises from L4-S4
What is sciatic nerve?
The largest nerve of the sacral plexus is actually two nerves in one sheath
What is tibial nerve? (sciatic nerve)
Innervates most of the posterior lower limb
What is common fibular? (sciatic nerve)
Innervates muscles of the lower leg
The spinal circuits
sensory receptor -> sensory neuron -> interneuron -> Integrating center -> motor neurons -> effector
