Spinal cord

Question 1

Describe the Spinal Cord

Answer 1

Roughly cylindrical (about 45 cm long)
Continuous: Above with medulla oblongata – at the level of foramen magnum
Tapers below into conus medullaris – at the level of the lower border of L1

Question 2

What is the Cervical Enlargement of the Spinal Cord?

Answer 2

• Contains Roots C5- T1
• Forms the brachial plexus
• opposite vertebra

Question 3

What is the Lumbosacral enlargement of the spinal cord?

Answer 3

• Roots L2 to S3
• Lumbar and sacral plexus
• T9 to L1

Question 4

Spinal Cord at 3rd month of fetal life

Answer 4

occupies the full extent of the vertebral canal (S2)

Question 5

Spinal Cord at Birth

Answer 5

reach the level of L3 (due to rapid growth of vertebral and dura mater than the spinal cord)

Question 6

Spinal cord by adolescence

Answer 6

reach a definitive position approximately at the level of the disc between L1 and L2 (due to further differential growth)

Question 7

What is the Filum Terminal?

Answer 7

At the apex of conus medullaris – the prolongation of pia mater is known as Filum terminal
it extends among the roots of the cauda equina

Question 8

What is a Lumbar Punture?

Answer 8

A Lumbar tap (puncture) is carried out to obtain a sample of CSF for examination
subarachnoidal space (CSF space) is used to inject antibiotics, chemotherapeutic agents, and anesthetics.

Question 9

What is the Anatomical basis for the lumbar puncture?

Answer 9

Spinal cord ends at the lower border of L1 Subarachnoid space extends to the lower border of S2

Question 10

What is the ideal site for a lumbar puncture?

Answer 10

below the 1st lumbar vertebra
between L4 and L5
in the lateral flexed position

Question 11

List the structures pierced when performing a lumbar puncture.

Answer 11

1. Skin
2. Superficial Fascia
3. Supraspinous ligament
4. Interspinous ligament
5. Ligamentum flavum
6. Areolar tissue containing internal vertebral venous plexus
7. Dura Mater

Question 12

Why is only a small volume aspirated in a lumbar puncture?

Answer 12

can lead to herniation of the brain matter
especially in case of high intracranial pressure

Question 13

What is regarded as a spinal segment?

Answer 13

A region of the spinal cord that gives rise to a single spinal nerve.

Question 14

What forms a spinal nerve?

Answer 14

A number of rootlets arising from the spinal cord
Within the subarachnoid space

Question 15

How many pairs of spinal nerves from the spinal cord?

Answer 15

31

Question 16

Components of a basic spinal nerve.

Answer 16

Ventral/ anterior root – motor/ efferent root
Dorsal/ posterior root – Sensory/ afferent root

Question 17

Where do the ventral and dorsal roots of a spinal cord unite?

Answer 17

they pass through the subarachnoid space
unite in the intervertebral formaina

Question 18

Where doe the posterior root ganglion lie?

Answer 18

intervertebral foramen

Question 19

The general internal structure of the spinal cord.

Answer 19

The inner core of grey matter (surrounding the central canal)
Enclosed by an outer covering of white matter
almost divided into two halves by the anterior median fissure and the posterior median sulcus

Question 20

What is spinal grey matter?

Answer 20

H-shaped pillar:
Dorsal/ Posterior grey horn
Ventral/ Anterior grey horn
Connected by Grey rami communicants

Question 21

How is the spinal grey matter different in the thoracic and lumbar regions?

Answer 21

A small lateral horn is present

Question 22

What are the 4 nerve cell groups in the dorsal grey horn?

Answer 22

1. Substantia Gelatinosa
2. Nucleus Propria
3. Nucleus Dosalis (Clarke Column)
4. Visceral afferent nucleus

Question 23

The 2 nerve cell groups that are present throughout the spinal cord.

Answer 23

Substantia Gelatinosa
Nucleus Propria (Main cell bulk)

Question 24

Where is the Nucleus dorsalis?

Answer 24

C8 -L4

Question 25

Where is the Visceral Afferent Nucleus?

Answer 25

T1-L3

Question 26

Sensation received by substantia gelatinosa

Answer 26

Pain
Temperature
touch

Question 27

Sensation received by Nucleus Propria

Answer 27

Proprioception
2 Point Discrimination
Vibration

Question 28

Sensation received by the Nucleus Dorsalis

Answer 28

proprioception

Question 29

sensation received by the Visceral Afferent Nucleus

Answer 29

Visceral afferent information