Spinal Cord And Spinal Nerve

Front 1

What does the spinal cord extend from?

Back 1

From the foramen magnum of the skull to the disc opposite L1 and L2

Front 2

Where is the cervical enlargement?

Back 2

From C4 to T1. Need additional neurons for innervation of upper limbs

Front 3

Where is the lumbosacral enlargement?

Back 3

From L2 to S3. Additional neurons needed for innervation of lower limbs

Front 4

What is the conus medullaris?

Back 4

Very end of spinal cord. The tapered end of the spinal cord which includes sacral spinal cord segments

Front 5

How many spinal cord segments are there?

Back 5

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

31 pairs of spinal nerves; each segment gives rise to a pair of spinal nerves

Front 6

What kind of nerves are in the lateral horn? in the intermediate gray?

Back 6

Lateral horn has autonomic motor while intermediate gray has interneurons

Front 7

What are the three layers of the meninges?

Back 7

Dura mater, Arachnoid, Pia mater

Front 8

Describe the dura mater

Back 8

The outermost later.
-composed of dense connective tissue
-2 layers: periosteal layer (attaches to vertebrae) and meningeal layer (envelopes spinal cord)
-Between the periosteal and meningeal layers in an epidural space (fat filled and has a venous plexus)
-Between the meningeal layer and Arachnoid is a subdural space which is just a potential space

Front 9

Describe the Arachnoid

Back 9

-Located deep to the dura
-Is avascular (no vessels)
-tissue is thin and transparent
-deep to arachnoid is the subarachnoid space (filled with CSF)

Front 10

What is a lumbar cistern?

Back 10

-inferior part of the subarachnoid space
-located in lumbar region
-region where samples of CSF can be taken from
-ends inferiorly to at S2 vertebral level

Front 11

Describe Pia Mater

Back 11

-Deepest meningeal layer
-Firmly attached to surface of spinal cord
-Cannot be dissected grossly

Front 12

What is the filium Terminale?

Back 12

-threadlike strand of the pia mater that leaves the conus medullaris and descends among the nerve roots of the cauda equina.
-Courses inferiorly through the middle of the lumbar cistern and is surrounded by the cauda equina (bundle of spinal roots)
-Becomes covered by the arachnoid and dura inferior to the S2 vertebral level to form the coccygeal ligament

Front 13

What is the coccygeal ligament?

Back 13

This ligament anchors the spinal cord and meninges inferiorly to the coccyx

Front 14

What is the spinal nerve made of?

Back 14

Union of dorsal and ventral roots.
-contains both sensory and motor axons.
-leaves vertebral column via intervertebral foramen
-distal to the intervertebral foramen, it divides into two braches (rami)

Front 15

What is the dorsal primary ramus?

Back 15

-different from dorsal root
-has both sensory and motor fibers
-innervates skin and deep muscles of the back

Front 16

What is the ventral primary ramus?

Back 16

-bigger than dorsal ramus
-innervates upper and lower limbs, and anterolateral trunk
-innervates superficial and intermediate muscles of the back
-contains both sensory and motor fibers
-contributes to major plexuses in the body (brachial plexus)

Front 17

What are communicating rami?

Back 17

White communicating rami contains myelinated axons of preganglionic symp. neurons and afferent axons from visceral organs

Gray communicating ramus contains postganglionic symp. axons

Front 18

What is the cauda equina?

Back 18

-bundle of spinal nerve roots in the subarachnoid space caudal of the termination of the spinal cord
-dorsal and ventral roots of lower lumbar and sacral spinal nerves
-sacral end of spinal cord (conus medullaris) is opposite the disc between L1 and L2
-lower spinal nerve roots must travel within the lumbar cistern to reach their respective intervertebral foramina
-within the lumbar cistern, they surround the filium terminale

Front 19

What are dermatomes?

Back 19

-specific skin segments innervated by a specific spinal nerve
-dermatome segments tend to overlap

Front 20

What are myotomes?

Back 20

-specific muscles that receive innervation by a particular spinal nerve
-muscles are usually innervated by two or more spinal nerves

Front 21

What is a plexus?

Back 21

The mixing and sorting of specific spinal nerves for distribution to muscles and skin in the periphery

Front 22

What is the brachial plexus?

Back 22

-formed by the ventral primary rami of spinal nerve segments C5 to T1
-nerves that innervate the upper limb