Spinal Cord and Spinal Nerves 16

Cervical Part

is the superior most region of the spinal cord. It is continuous with the medulla oblongata. The cervical part contains motor neurons whose axons contribute to the cervical spinal nerves and receives input from sensory neurons through.

Thoracic part

lies inferior to the cervical part. It contains the neurons for the thoracic spinal nerves.

Lumbar part

is a shorter segment of the spinal cord that contains the neurons for the lumbar spinal nerves.

Sacral part

lies inferior to the lumbar part and contains the neurons for the sacral spinal nerves.

Coccygeal part

is the most inferior tip of the spinal cord. (Some texts consider the coccygeal part a portion of the sacral part of the spinal cord.)

Conus Medullaris

is the inferior end of the spinal cord (usually at the level of the first lumbar vertebra).

Cauda equina

Nerve roots collectively called this; project inferiorly from the spinal cord. These nerve roots are so named because they resemble a horse’s tail.

Filum Terminale

Within the cauda equina is this. The filum terminale is a thin strand of pia mater that helps anchor the conus medullaris to the coccyx.

Posterior Median Sulcus

A narrow groove; dips internally on the posterior surface, and a slightly wider groove.

Anterior Median Fissure

is viewed on the anterior surface.

Cervical Enlargement

located in the inferior cervical part of the spinal cord, contains the neurons that innervate the upper limbs.

Lumbosacral enlargement

extends through the lumbar and sacral parts of the spinal cord and innervates the lower limbs.

Spinal Cord Meninges

The spinal cord is protected and encapsulated by this; which are continuous, spaces between some of the meninges have clinical significance.

Epidural space

lies between the dura mater and the periosteum covering the inner walls of the vertebra, and houses areolar connective tissue, blood vessels, and adipose connective tissue.

Dura Mater

Deep to the epidural space is the outermost of the meninges, is this; consists of a single meningeal layer.

Subdural Space; Arachnoid Mater

in most anatomic and histologic preparations, a narrow this; separates the dura mater from this,

Subarachnoid Space

Deep to the arachnoid matter is ___, which is a real space filled with cerebrospinal fluid.

Pia mater

deep to the subarachnoid space, is a delicate, innermost meningeal layer composed of elastic and collagen fibers.

Denticulate Ligaments

are paired, lateral triangular extensions of the spinal pia mater that attach to the dura mater. These ligaments help suspend and anchor the spinal cord laterally to the dura mater.

Gray matter

in the spinal cord is centrally located, and its shape resembles a letter H or a butterfly. The gray matter may be subdivided into the following components: anterior horns, lateral horns, posterior horns, and the gray commissure

Anterior horns

are the left and right anterior masses of gray matter. The anterior horns primarily house the cell bodies of somatic motor neurons, which innervate skeletal muscle.

Lateral Horns

occur in the T1

Posterior Horns

are the left and right posterior masses of gray matter. The axons of sensory neurons and the cell bodies of interneurons are located in the posterior horns. (The cell bodies of these sensory neurons are not found in the __; rather, they are located in the posterior root ganglia.)

Gray commissure; Central Canal

is a horizontal bar of gray matter that surrounds a narrow

Nuclei

Within these regions of gray matter are various functional groups of neuron cell bodies called

Funiculus

White matter on each side of the cord is also partitioned into three regions, each called a _

Posterior funiculus

lies between the posterior gray horns on the posterior side of the cord and the posterior median sulcus.

Lateral Funiculus

is the laterally

Anterior Funiculas

is composed of tracts of white matter that occupy the space on each anterior side of the cord between the anterior gray horns and anterior median fissure.

White commissure

The anterior funiculi are interconnected by the .

Tracts

The axons within each white matter funiculus are organized into smaller structural units called __.

Fasciculi

Individual tracts conduct either sensory impulses (ascending tracts from the spinal cord to the brain) or motor commands (descending tracts from the brain to the spinal cord) only.