SPINE AND GRAY MATTER

How many spinal nerves are there?

31 pairs
8 cervical
12 thoracic
5 lumbar
5 sacral
1 coccygeal

film terminale

anchors spinal cord to coccyx

medullary cone

tapered tip of spinal cord

cauda equina

collection of spinal nerves below the end of the spinal cord

ventral median fissure

the anterior, more open of the two grooves that partially divide the spinal cord into left and right halves

Doral median sulcus

posterior groove of the spinal cord

posterior horn

interneurons that receive somatic and visceral sensory input

anterior horn

somatic motor neurons whose axons exit the cord via ventral roots

dorsal root

the sensory branch of each spinal nerve

ventral root

contains axons of motor neurons

dorsal root ganglion

contains cell bodies of sensory neurons

Meningeal Branches of the Spinal Nerves

are a number of small nerves that branch from the spinal nerve near the origin of the anterior and posterior rami. Supply meningeas

gray ramus communicans

contains postganglionic fibers that innervate glands and smooth muscles in the body wall or limbs

white ramus communicans

carries the preganglionic fibers into a nearby sympathetic chain ganglion

dorsal ramus

innervates the muscles, joints, and skin of the back

ventral ramus

the anterior division of spinal nerves that communicate with the muscle and skin of the anterior and lateral trunk

Marginal nucleus/lamina 1

extends the entire length of the spinal cord, most dorsal in posterior (dorsal) column, and receives afferent fibers carrying pain, temperature, and light touch sensations.

gelatinosa substantia

extends the entire length of the spinal cord. These cells receive sensory input related to pain, temperature, and light touch information.

nucleas proprius

receives pain, light touch, and temperature sensations. (lamina 3 and 4)

rex lamina 5

its lateral aspect is referred to as the reticular formation

rex lamina 6

-Receives sensory information from muscle spindles (involved in proprioception).
-Sends information to the brain via ipsilateral spinocerebellar pathways

Clarke's nucleus

, found in the intermediate zone of the spinal cord, sends unconscious proprioception to the cerebellum?

intermediomedial nucleus

contains preganglionic sympathetic neurons as sympathetic centre of spinal cord extends through C8-L2 segments of spinal cord

intermediolateral nucleus

Found at T1-L3.
Contains somas of preganglionic sympathetic motor neurons that project to sympathetic ganglia.

Rexed lamina 8

Motor Interneurons, Ventral Horn, interneurons in the medial aspect of ventral horn that coordinate the activities motor output to skeletal muscle

Medial group of spine (rex lamina 9)

extends almost the entire length of the spinal cord, group provide innervation for the skeletal muscles of the abdomen, the intercostal muscles, and the muscles of the neck.

central group (rex lamina 9)

is present only in the cervical and lumbosacral segments of the spinal cord.
-phrenic nucleus
-accessory nucleus

Rex lamina 10

the grey matter that surrounds the central canal of the spinal cord is known as the gray commissure; extends the entire length of the spinal cord.