Nervous System - Spinal Cord

Question 1

Gray Matter

Answer 1

• shaped like a butterfly
• primary contains neuronal cell bodies (nuclei)
• contains ventral and dorsal horns
• lateral horns located in thoracic and sacral section of the spinal cord

Question 2

Lateral Horns

Answer 2

• part of gray matter in spinal cord only located in the thoracic and sacral regions of the spinal cord

Question 3

White Matter

Answer 3

• surrounds gray matter in the spinal cord
• primarily contains neuron axons (tracts)

Question 4

Nuclei

Answer 4

• cell bodies in the CNS
• gray matter in the spinal cord

Question 5

Tracts

Answer 5

• axons in the CNS
• located primarily in the white matter

Question 6

Vertebral Canal

Answer 6

• the channel through the center of the vertebral column
• formed by successful vertebral foramina“stacked” on top of one another

Question 7

Sacrum

Answer 7

• sacral region of the vertebral column
• five sacral vertebrae fused to form the sacrum

Question 8

Coccyx

Answer 8

• the inferior structure of the vetebral column
• formed by the fusion of 3-4 coccygeal vertebrae

Question 9

Intervertebral Disc

Answer 9

• the joint between two vertebral bodies - a symphysis (two bones connected by cartilage)
• the symphysis that connects the vertebrae in the spinal column

Outer Layer - Anulus Fibrosis (fibrocartilage)

Inner Layer - Nucleus Pulposis (gelatinous core)

• act as shock absorbers and allow movement of the vertebral column

Question 10

Anulus Fibrosis

Answer 10

• the other layer of the intervertebral disc
• made of fibrocartilage

Question 11

Nucleus Pulposis

Answer 11

• the inner core of the intervertebral disc
• gelatenous
• slips past the anulus fibrosis when one has a slipped disc

Question 12

Intervertebral Foramina

Answer 12

• openings on the lateral aspect of the vertebral column that permits passage of vessels and nerves into or out of the vertebral canal
• formed by superior and inferior vertebral notches of the adjacent vertebrae

Question 13

Vertebral Foramina

Answer 13

• the space located within the vertebra where the spinal cord passes through

Question 14

Conus Medullaris

Answer 14

• the terminal (most inferior) part of the spinal cord
• located at approximately the L2 vertebral level in adults (and as far as L3 in infants)

Question 15

Location of an LP or spinal tap

Answer 15

Between L3 and L5 so as to access CNS but not hit the spinal cord (which ends at L2 at the conus medullaris)

Question 16

Spinal Cord Enlargements

Answer 16

• two swellings in the spinal cord
• reflect the large number of neurons pressent in those areas (generally that innervate the limbs/extremities
• Cervical and Lumbar

Question 17

Cervical Enlargement

Answer 17

• found bw C5-T1
• neruons found here innervate the upper extremities

Question 18

Lumbar Enlargement

Answer 18

• found bw L1-S3
• neruons here innervate the lower extremity

Question 19

Meninges

Answer 19

• the layers of connective tissue that surround the brain and spinal cord

Question 20

Dura Mater

Answer 20

• the thick outermost layer of the meninges

Question 21

Arachnoid Mater

Answer 21

• the middle layer of the meninges that resembles a spider web
• lies up against the dura mater

Question 22

Pia Mater

Answer 22

• the innermost layer of the meninges
• intimately applied to the spinal cord
• the most delicate membrane enclosing the brain and spinal cord

Question 23

Epidural Space

Answer 23

• aka extradural space
• the area between the dura mater and the vertebral canal
• filled with fat and also contains the internal vertebral venous plexus
• begins at the foramen magnum and ends inferiorly at the sacral hiatus
• often local anasthesia injected in order to anesthetize the nerve roots (i.e. epidural)

Question 24

Dural Sac

Answer 24

• aka thecal sac
• a tube/sac formed by the dura mater around the spinal cord
• sac begins at the foramen magnum where it is continuous with the dura mater around the brain
• extends approximately to the S2 vertebral level (varies bw S1-S3) –> continuous with the outer part of the external filum terminale (coccygeal ligament)
• has sleeve-like projections that surround the spinal nerve roots as they exit the vertebral canal

Question 25

**Internal Filum Terminale**

Answer 25

- a thin strand of pia mater that continues inferiorly passed the conus medullaris - becomes invested in the dura mater at the inferior limit of the dural sac

Question 26

**External Filum Terminale**

Answer 26

- at the end of the dural sac where the internal filum terminale becomes invested in the dura mater - essentially the pia mater + dura mater - aka **coccygeal ligament** - anchors the spinal cord inferiorly by passing through the sacral hiatus and attaching to the coccyz

Question 27

**Subdural Space**

Answer 27

- potential space between the dural mater and the arachnoid mater

Question 28

**Subarachnoid Space**

Answer 28

- located bw the arachnoid mater and the pia mater - contains CSF (cerebrospinal fluid) - extends to the end of the dural sac (S2) thus allowing CSF to be sampled without puncturing the spinal cord - continuous with the subarachnoid space of the brain

Question 29

**Denticulate Ligaments**

Answer 29

- lateral tooth-shaped extensios of the _pia mater_ that penetrate the arachnoid and fuse to the dura mater to help anchor the spinal cord within the vertebral canal

Question 30

Answer 30

Question 31

Answer 31

Question 32

**Vertebral Column**

Answer 32

- 33 stacked vertebrae 7 Cervical 12 Thoracic 5 Lumbar 5 Sacral 4 Coccygeal

Question 33

Fill in the meninges

Answer 33