chapter 9 spinal cords and meninges

gray matter

• area of cell bodies with their associated neuron parts within the CNS

• contains enlargements known as the dorsal and ventral horns

white matter

• area of primarily myelinated axons within the CNS

• divided into posterior, lateral, and anterior funiculi

funiculi

columns of nerve bundles containing tracts that course up and down, to and from the brain

dorsal root

arises from dorsal surface of the spinal cord, contains only sensory neurons

dorsal root ganglion

• enlarged portion of the dorsal root

• defined as an area of cell bodies outside of the CNS

• contains cell bodies of sensory neurons

ventral root

arising from the ventral surface of the spinal cord, contains axons of motor neurons only

spinal nerve

where the ventral root joins the dorsal root

what does the spinal nerve divide into

ventral and dorsal rami

ventral ramus

• larger

• supplies the entire anterior trunk

• contains motor and sensory neurons

dorsal ramus

• smaller

• supplies structures of the back( deep back and skin of back)

• contains motor and sensory neurons

sensory neuron

• also called afferent neurons

• carry impulses towards the brain and spinal cord

interneuron neuron

courses between other neurons

motor neuron

• also called efferent neurons

• carry impulses away from the brain and spinal cord

spinal cord

• long cylindrical mass of nervous tissue

• takes up upper 2/3 of the vertebral canal

• connected to the brain superiorly, then is continuous with medulla oblongata

conus medullaris

lower end of the spinal cord with a conical shape

cervical enlargement

located from C5- T1

lumbosacral enlargement

located from L1-S3

cauda equina

• below LV2

• occupies the vertebral canal

• consists of long roots of spinal nerves and filum terminale

how many pairs of spinal nerves

31

cervical region

number of nerve pairs: 8

nerve names: C1- C8

Thoracic region

number of nerve pairs: 12

nerve names: T1-T12

Lumbar region

number of nerve pairs: 5

nerve names:L1-L5

sacral region

number of nerve pairs:5

nerve names:S1-S5

coccygeal

number of nerve pairs:1

nerve names:Cx1

arteries supplying the spinal cord

• 1 anterior spinal

• 2 posterior spinal

meninges

connective tissue that surrounds brain and spinal cord

meninges consist of

from external to internal

• dura mater

• arachnoid mater

• pia mater

dura mater

• outermost meninx

• made of dense, tough, fibrous connective tissue

epidural space

• space external to the spinal dura mater

• contains adipose tissue in the form of globules of fat, and also vertebral venous plexus(batson’s veins)

arachnoid mater

• middle meninx

• delicate, loose, net-like material

• courses and extends through foramen magnum

subanachnoid space

• separates anachnoid and pia mater

• contains cerebrospinal fluid

pia mater

• innermost meninx

• delicate connective tissue that adheres to brain and spinal cord

• extends from foramen magnum

denticulate ligament

paired, triangular extensions of the spinal pia mater that securely anchor the spinal cord to the dura mater within the vertebral column

filum terminale

fibrous connective tissue that extends posteriorly from the end of the spinal cord (the conus medullaris) to anchor the spinal cord to the coccyx