A & P - Nervous System, Spinal Cord, Spinal Meninges, And Nerve Roots

Front 1

Name the wide groove on the anterior (ventral) side of the spinal cord.

Back 1

Anterior median fissure

Front 2

Name the narrow furrow on the posterior (dorsal) side of the spinal cord.

Back 2

Posterior median sulcus

Front 3

What is the name of the crossbar of the H of gray matter?

Back 3

Gray commisure

Front 4

What is the Gray commisure?

Back 4

Crossbar of the H of gray matter.

Front 5

Give the name of the small space within the gray commisure that extends the entire length of the spinal cord and is filled with cerebrospinal fluid.

Back 5

Central canal

Front 6

What is the central canal?

Back 6

Small space within the gray commisure that extends the entire length of the spinal cord and is filled with CSF

Front 7

What are the horns of the spinal cord?

Back 7

The horns are the legs of the gray matter H of the spinal cord.

There are posterior horns, anterior horns, and smaller lateral horns.

Front 8

What lies within the anterior horns?

Back 8

Somatic motor nuclei

Front 9

What lies within the lateral horns?

Back 9

Cell bodies of autonomic motor nuclei

Front 10

What lies within the posterior horns?

Back 10

1) Cell bodies and axons of interneurons

2) Axons of incoming sensory neurons

Front 11

What is a tract?

What is a nerve?

Back 11

Tracts are bundles of axons in the CNS

Nerves are bundles of axons in the PNS

Front 12

What is the name for a bundle of nerves in the CNS?

In the PNS?

Back 12

CNS - Tract

PNS - Nerve

Front 13

Where do the cell bodies of somatic motor neurons lie?

Back 13

Anterior horn

Front 14

Where do the cell bodies of autonomic motor neurons lie?

Back 14

Lateral horn

Front 15

Where do the cell bodies of somatic sensory neurons lie?

Back 15

Posterior root ganglion

Front 16

Name the two tracts that carry somatic sensory information to the brain.

Back 16

1) Posterior column-medial lemniscus pathway

2) Anterolateral or Spinothalamic pathway

Front 17

Which somatic sensory modalities are carried along the posterior column-medial lemniscus pathway?

Back 17

Vibration and proprioception

Front 18

Where do neurons carrying vibration and proprioception decussate?

Back 18

In the medulla

In other words, vibration and proprioception travel up the ipsilateral side of the cord

Front 19

Which somatic sensory modalities are carried along the anterolateral (spinothalamic) pathway?

Where is this pathway located?

Back 19

Pain, temperature

Located anterior to the anterior horn (anterolateral)

Front 20

Where do neurons carrying pain and temperature decussate?

Back 20

Right away upon entering the spinal cord

In other words, pain and temperature are travel up the contralateral side of the spinal cord.

Front 21

A man presents with unilateral loss of vibration and proprioception on the right side below the level of the nipple line.

Where is the lesion?

Back 21

Right posterior column of the spinal cord

Front 22

A woman presents with unilateral pain and temperature sensation on the left side below the level of the nipple line.

Where is the lesion?

Back 22

Right anterolateral/spinothalamic tract of spinal cord.

Front 23

What is the singular of meninges?

What is the etymology of this word?

Back 23

Meninx

Greek for membrane

The meninges therefore are the membranes.

Front 24

Name the three spinal meninges from superficial to deep.

Back 24

1) Dura mater
-below the dura mater lies the thin subdural space
-the arachnoid mater lies practically just underneath the dura

2) Arachnoid mater
-below the arachnoid mater lies the wider subarachnoid space

3) Pia mater

Front 25

What lies within the posterior (dorsal) root?

Back 25

The posterior root ganglion, which contains cell bodies of somatic sensory neurons.

Front 26

What lies within the anterior (ventral) root?

Back 26

There is no ganglion here as there is in the posterior root, only the axons of somatic motor nerves.

Front 27

How many sets of paired spinal nerves are there?

Back 27

31 sets of spinal nerves

8 cervical
12 thoracic
5 lumbar
5 sacral
1 coccygeal

Front 28

Where do spinal nerves exit the spinal canal?

Back 28

Spinal nerves C1-C7 exit through the intervertebral foramen ABOVE their correspondingly-numbered vertebra.

For example, C3 exits the intervertebral foramen between C2 and C3.

Spinal nerve C8 is exceptional in that their is no vertebra C8. This spinal nerve passes through the intervertebral foramen between C8 and T1.

From T1 down, the spinal nerves exit through the intervertebral foramen BELOW the correspondingly-numbered vertebra.

For example, T11 exits the intervertebral foramen between T11 and T12.

Front 29

Characterize the length of the spinal cord relative to the length of the vertebral column.

What is the reason for this discrepancy?

Back 29

The spinal cord is much shorter than the vertebral column, ending at the the level of the intervertebral foramen between L1 and L2.

The reason is that the spinal cord stops growing at around age 4 while growth of the vertebral column continues.

Front 30

What is the cauda equina?

Back 30

The cauda equina is the grouping of nerve roots for L1-C1 that angle inferiorly in the vertebral canal from the end of the spinal cord until they exit through the appropriate intervetebral foramen.

Front 31

Where does spinal nerve C4 exit the spinal canal?

Back 31

Intervertebral foramen between C3 and C4

Front 32

Where does spinal nerve C8 exit the spinal canal?

Back 32

Intervertebral foramen between C8 and T1

Front 33

Where does spinal nerve T5 exit the spinal canal?

Back 33

Intervertebral foramen between T5 and T6

Front 34

Where does spinal nerve L4 exit the spinal canal?

Back 34

Intervertebral foramen between L4 and L5

Front 35

Which nerve roots/spinal nerves comprise the cauda equina?

Back 35

L1-L5

S1-S5

C1

Front 36

Which is the last spinal nerve to come off the spinal cord?

Back 36

Trick question: they all come off the spinal cord!

The so-called cauda equina is a group of nerves that descend through the spinal canal until they can exit at their appropriate foramen, but they're still all attached to the spinal cord at the superior end.