The Spinal Cord

Question 1

Where do the C1 and C2 nerve roots exit the vertebral column?

Answer 1

• C1 exits above the atlas

- C2 exits below the atlas

Question 2

Where do the spinal nerves below C2 exit the vertebral column?

Answer 2

Below the named vertebra

Question 3

Why is the spinal cord enlarged at the level of the plexuses?

Answer 3

There are more neuron bodies.

Question 4

Which plexus causes the greatest enlargement in the spinal cord?

Answer 4

• The cervical plexus

Question 5

At what levels does the thoracolumbar enlargment occur?

Answer 5

From T11 until its greatest circumference at L1.

Question 6

What is the termination of the spinal cord named?

Answer 6

Conus medularis.

Question 7

What is the continuation of axons pass the conus medaliaris termed?

Answer 7

The cauda equina.

Question 8

What are the 3 protective layers about the spinal cord from outer to inner?

Answer 8

• Dura mater
• Arachnoid mater
• Pia mater

Question 9

Where is the subdural space found?

Answer 9

Between the dura and arachnoid mater. (This is a potential space that can fill with fluid)

Question 10

Where is the subarachnoid space found?

Answer 10

• Between the arachnoid mater and pia mater.

Question 11

What is found with in the aubarachnoid space?

Answer 11

CSF.

Question 12

What are the 2 mechanical stabilizations of the spinal cord?

Answer 12

• Filum Terminal/ Terminal Ligament

- Denticulate Ligaments

Question 13

What is the filum terminal?

Answer 13

• An extension of pia mater that attaches from the caudal portion of the spinal cord to the sacrum, anchoring the cord.

Question 14

What are the denticulate ligaments?

Answer 14

• An extension of the pia mater that extends laterally from the spinal cord and attaches to the arachnoid, and dura matter, which is attached to bone.

Question 15

What is the major non-mechanical stabilizer of the spinal cord?

Answer 15

• Cerebrospinal fluid within the subarachnoid that cannot be compressed

Question 16

What protective coverings of the spinal cord extend with the cauda equina from L1 to the coccyx?

Answer 16

• The arachnoid and dura mater

Question 17

How is the ventral horn organized in terms of distal/ proximal innervations?

Answer 17

• Lateral portions innervate more distal body parts

- Medial portions innervate more proximal muscles

Question 18

How is the ventral horn organized in terms of flexors/ extensors?

Answer 18

• Dorsal portion innervates flexors

- Ventral portion innervates extensors

Question 19

What is the organizing of neurons in the ventral horn according to function called?

Answer 19

• Somatotopic arrangement

Question 20

What are 2 methods of organization of the neurons within the gray matter of the spinal cord?

Answer 20

• Nuclei arrangements

- Rex laminae arrangements

Question 21

Which horn works well with a nuclei arrangement? Which horn works well with Rex laminae arrangments?

Answer 21

Ventral: Nuclei
Dorsal: Rex laminae

Question 22

Which rex lamina make up the dorsal horn?

Answer 22

1 - 6

Question 23

Which rex lamina make up the venral horn?

Answer 23

7 - 12

Question 24

Which rex lamina are the cell pools of the ventral horn?

Answer 24

IX

Question 25

Which rex lamina is intermediate gray?

Answer 25

VII

Question 26

Which rex lamina is interneurons of the ventral horns?

Answer 26

VIII

Question 27

Which rex lamina is the commisure of the spinal cord gray matter?

Answer 27

X

Question 28

Which rex lamina is the substantia gelatinosa?

Answer 28

Lamina II

Question 29

Which rex lamina is the marginal zone?

Answer 29

Lamina I

Question 30

Which rex lamina is the nucleus proprius?

Answer 30

Laminae III and IV

Question 31

What is another name for the marginal zone/ lamina I?

Answer 31

- Posteromarginal nucleus

Question 32

What are the 2 functions of the 1st rex lamina?

Answer 32

- Sensory relay for: Pain and Temperature | - Contributes some fibers to LSTT (??? what is this ???)

Question 33

What are the 3 functions of the 2nd rex lamina?

Answer 33

- Receives afferent information from unmyelinated & thinly myelinated fibers - Receives information from higher centers (brain stem) - Modulation of function (especially pain)

Question 34

What are the 3 functions of the 3rd and 4th rex laminae?

Answer 34

- Sensory processing - Penetrated by dendrites of large neurons in lamina V - The same functions as lamina II, but also receives information from touch afferents

Question 35

What are the 2 functions of 5th rex lamina?

Answer 35

- Receives afferent fibers and interneurons from II, III & IV - Receives fibers from corticospinal & rubrospinal tracts

Question 36

What is the function of the 6th rex lamina?

Answer 36

- Receives 1st degree proprioceptive input from muscles and tendons

Question 37

What is the function of the 9th rex lamina?

Answer 37

- The motor nuclei that innervate skeletal muscles

Question 38

What type of neurons are found in the 9th rex lamina?

Answer 38

- Alpha and gamma motorneurons