Spinal Cord

Question 1

Where does the spinal cord extend from in adults?

Answer 1

The spinal cord extends down the vertebral canal from the medulla oblongata (the inferior portion of the brain stem) to the level of the L1-2 vertebra

Question 2

How does the length of the spinal cord compare to the vertebral column?

Answer 2

The spinal cord is shorter than the vertebral column.

Question 3

What is the name of the tapered end of the spinal cord?

Answer 3

Its caudal end tapers to a point called the conus medullaris.

Question 4

What extends inferiorly from the conus medullaris?

Answer 4

Extending inferiorly from this point is the filum terminale, a strand of fibrous tissue that anchors the spinal cord to the coccyx.

Question 5

which level does the spinal cord normally end?

Answer 5

L1-2 vertebra

Question 6

What are the two regions of increased diameter in the spinal cord?

Answer 6

Cervical enlargement (C4-T1 vertebrae) – Gives rise to the spinal nerves that innervate the upper limbs

Lumbar enlargement (T9-T12 vertebrae) – Gives rise to the spinal nerves that innervate the lower limbs

Question 7

How many segments is the spinal cord divided into?

Answer 7

The spinal cord is divided into 31 segments, each giving rise to a pair of spinal nerves.

Question 8

What is the function of plexuses in the spinal cord?

Answer 8

Plexuses have peripheral nerve branches that supply sensory and motor innervation to the upper and lower limbs.

Question 9

What is the arrangement of white and grey matter in the spinal cord cross-section?

Answer 9

When looked at in cross-section, the spinal cord has a ring of white matter surrounding a core of grey matter.

Question 10

How is the spinal cord divided into left and right sides?

Answer 10

There are two grooves that extend into the white matter and separate the spinal cord into left and right sides.

Question 11

What is found in the center of the grey matter of the spinal cord?

Answer 11

In the center of the grey matter is a central canal, which runs the length of the spinal cord and is filled with cerebrospinal fluid (CSF).

Question 12

How is the grey matter on each side of the spinal cord divided?

Answer 12

On each side of the spinal cord, the grey matter can be separated into two or three regions, depending on the level of the spinal cord.

Question 13

What is the anterior protrusion of grey matter called and what does it contain?

Answer 13

The anterior protrusion of grey matter is called the anterior or ventral horn, which contains the cell bodies of neurons involved with the somatic motor pathways.

Question 14

What is the posterior protrusion of grey matter called and what does it contain?

Answer 14

The posterior protrusion of grey matter is called the posterior or dorsal horn, which contains the cell bodies of neurons involved with the somatic sensory pathways.

Question 15

In which segments of the spinal cord is there a lateral protrusion of grey matter, and what is it called?

Answer 15

In the T1 to L2 and S2 to S4 spinal cord segments, there is a lateral protrusion of grey matter called the lateral horn, which contains the cell bodies of neurons involved in the autonomic motor pathways.

Question 16

what do each of the columns in the spinal cord contain?

Answer 16

ascending (sensory) tracts and/0r descending (motor) tracts.

Question 17

How many regions can the white matter on each side of the spinal cord be separated into?

Answer 17

The white matter on each side of the spinal cord can be separated into three regions: anterior, posterior, and lateral columns.

Question 18

What effectively separates the anterior and lateral columns of the white matter?

Answer 18

The anterior horn effectively separates the anterior and lateral columns of the white matter.

Question 19

What are tracts in the context of the spinal cord?

Answer 19

Tracts are bundles of axons that transmit signals in one direction, either up or down the spinal cord.

Question 20

How are sensory and motor signals classified in the spinal cord?

Answer 20

Signals travelling up the spinal cord are classified as sensory signals, while those travelling down the spinal cord are classified as motor signals.

Question 21

How many pairs of cervical spinal nerves are there and what are their designations?

Answer 21

There are 8 pairs of cervical spinal nerves, designated as C1-C8.

Question 22

How many pairs of thoracic spinal nerves are there and what are their designations?

Answer 22

There are 12 pairs of thoracic spinal nerves, designated as T1-T12.

Question 23

How many pairs of lumbar spinal nerves are there and what are their designations?

Answer 23

There are 5 pairs of lumbar spinal nerves, designated as L1-L5.

Question 24

How many pairs of sacral spinal nerves are there and what are their designations?

Answer 24

There are 5 pairs of sacral spinal nerves, designated as S1-S5.

Question 25

How many pairs of coccygeal spinal nerves are there and what is their designation?

Answer 25

There is 1 pair of coccygeal spinal nerves, designated as Co1.

Question 26

Where does the anterior or ventral root emerge from and what does it contain?

Answer 26

The anterior or ventral root emerges from the anterolateral spinal cord and contains the axons of motor neurons whose cell bodies are in the anterior and lateral horns of the spinal cord.

Question 27

Where does the posterior or dorsal root emerge from and what does it contain?

Answer 27

The posterior or dorsal root emerges from the posterolateral spinal cord and contains the axons of sensory neurons whose cell bodies are in a ganglion that bulges out from the root.

Question 28

What is a ganglion and where is it located in relation to the central nervous system?

Answer 28

A ganglion is a cluster of cell bodies located outside the central nervous system.

Question 29

How do motor signals leave the spinal cord and how do sensory signals enter the spinal cord?

Answer 29

Any motor signals leaving the spinal cord do so via the anterior root, while any sensory signals entering the spinal cord do so via the posterior root.

Question 30

What types of neurons’ axons does the spinal nerve contain?

Answer 30

Since the spinal nerve is formed from the union of the anterior and posterior spinal nerve roots, it contains the axons of both sensory and motor neurons.

Question 31

Posterior (dorsal) root

Answer 31

Made up of axons of sensory neurons

Cell bodies are within a posterior (dorsal) root ganglion

Question 32

what are Spinal nerves made up of?

Answer 32

Made up of sensory & motor axons (“mixed”)

Question 33

what is the Anterior (ventral) root made up of and where are the cell bodies located?

Answer 33

Made up of axons of motor neurons
Cell bodies are within the anterior and lateral horns of the spinal cord

Question 34

How do the spinal nerves emerge from the vertebral column?

Answer 34

The spinal nerves emerge from the vertebral column between adjacent vertebrae through the intervertebral foramina (IVF).

Question 35

how do the C1-C7 spinal nerves exit in relation to their corresponding vertebrae?

Answer 35

C1-C7 spinal nerves exit superior to their corresponding vertebrae.

Question 36

Where does the C8 spinal nerve exit in relation to the vertebrae?

Answer 36

The C8 spinal nerve exits between C7 and T1.

Question 37

Where do the thoracic and lumbar spinal nerves exit in relation to their corresponding vertebrae?

Answer 37

Thoracic and lumbar spinal nerves exit inferior to their corresponding vertebrae.

Question 38

Through which structure does each spinal nerve exit the vertebral canal?

Answer 38

Each spinal nerve exits the vertebral canal via one of the intervertebral foramina located between each pair of vertebrae along the length of the vertebral column.

Question 39

How do C1-C7 spinal nerves exit in relation to their corresponding vertebrae?

Answer 39

C1-C7 spinal nerves exit superior to their corresponding vertebrae

Question 40

provide an example as to how the C6 spinal nerve exits:

Answer 40

the C6 spinal nerves exit superior to the C6 vertebra in the intervertebral foramina between C5 and C6.

Question 41

How do thoracic and lumbar spinal nerves exit in relation to their corresponding vertebrae?

Answer 41

Thoracic and lumbar spinal nerves exit inferior to their corresponding vertebrae

Question 42

provide an example as to how the T6 spinal nerves exit in relation to its corresponding vertebrae

Answer 42

the T6 nerves exit inferior to the T6 vertebra in the intervertebral foramina between T6 and T7.

Question 43

Why do most spinal nerve roots angle inferiorly before joining within their respective intervertebral foramina (IVFs)?

Answer 43

Most spinal nerve roots angle inferiorly before joining within their respective IVFs because the spinal cord is shorter than the vertebral column.

Question 44

Where do the nerve roots of the L2-Co1 spinal segments extend from, and where do they emerge from the vertebral canal?

Answer 44

The nerve roots of the L2-Co1 spinal segments extend caudally from the conus medullaris (along with the filum terminale) until they emerge from the vertebral canal at their respective levels.

Question 45

What is the term used to refer to the collection of fibers formed by the nerve roots of the L2-Co1 spinal segments?

Answer 45

This collection of fibers is referred to as the cauda equina because it resembles a horse’s tail.

Question 46

What is the filum terminale?

Answer 46

a strand of fibrous tissue that extends inferiorly from the conus medullaris, the tapered end of the spinal cord. It anchors the spinal cord to the coccyx, providing stability and support.

Question 47

What is the conus medullaris?

Answer 47

The conus medullaris is the tapered or cone-shaped end of the spinal cord. It marks the termination point of the spinal cord proper, typically occurring at the level of the first or second lumbar vertebra (L1 or L2).

Question 48

What is cauda equina syndrome?

Answer 48

Cauda equina syndrome is characterized by compression of the cauda equina, typically caused by a space-occupying lesion such as an intervertebral disc herniation or tumor, located in the vertebral canal below the conus medullaris.

Question 49

What are the signs and symptoms of cauda equina syndrome?

Answer 49

Signs and symptoms of cauda equina syndrome include weakness and/or pain in the lower limbs (usually bilateral), “saddle anesthesia” (numbness in the genitals, buttocks, and inner thighs), urinary and/or fecal incontinence, and sexual dysfunction.

Question 50

How is cauda equina syndrome usually treated?

Answer 50

cauda equina syndrome is usually treated with surgical decompression, involving the removal of the space-occupying lesion causing the compression.

Question 51

Why is early recognition and treatment of cauda equina syndrome vital?

Answer 51

to prevent long-term or permanent damage to the affected nerves or nerve roots.