Spinal Cord Anatomy

dorsal horn of spinal cord

#1 - location of ascending CNS neurons

ventral horn of spinal cord

contains cell bodies of MOTOR neurons

gray matter of spinal cord

location of the all the cell bodies within the spinal cord

white matter of spinal cord

myelinated axons of the spinal cord carrying action potentials either up to the brain or down to motor neuron cell bodies.

ventral roots of spinal cord

Carry motor output to periphery - muscles, glands, etc.

Dorsal root

carry sensory information into the spinal cord.

Dorsal Root Ganglion (DRG)

sensory neuron cell bodies

Varicella virus dormancy location

in the sensory neurons in the dorsal root ganglion - if reactivated, shingles results.

central canal

a cerebrospinal fluid channel in the center of the spinal cord

pia mater cross-section

the delicate innermost membrane enveloping the brain and spinal cord.

pia mater

#3 meninge that covers the spinal cord and brain tissue

arachnoid mater

weblike middle layer of the three meninges - where the cerebrospinal fluid is found

dura mater

thick, outermost layer of the meninges surrounding and protecting the brain and spinal cord

epidural anesthesia

Drug injection into the epidural space, usually the lumbar or caudal region, through a catheter to induce anesthesia

lumbar puncture (spinal tap)

the process of obtaining a sample of cerebrospinal fluid by inserting a needle into the subarachnoid space of the lumbar region

spinal nerve - cross-section

31 pairs of these leave the spinal cord

spinal nerves - longitudinal

How many spinal nerves are there?

31 pairs

8 cervical

12 thoracic

5 lumbar

5 sacral

1 coccygeal

brachial plexus

network of interlacing nerves found in the upper arm area

cervical plexus

lumbar plexus

A in this picture

sacral plexus

sciatic nerve

nerve extending from the base of the spine down the thigh, lower leg, and foot - part of the sacral plexus

phrenic nerve

innervates the diaphragm

Which plexus is the phrenic nerve part of?

cervical plexus

Spinal Nerve Impingement

Also called a pinched nerve or compressed nerve, refers to any pressure of pinching of a nerve root. Often caused by improper alignment of vertebrae.

herniated disc (slipped disc)

can result in spinal nerve impingement

epidural headache

If the needle goes through arachnoid mater, then cerebrospinal fluid can leak out and the loss of this fluid can cause enormous brain pain.