Spinal Cord Key Facts

Question 1

Conus medularis

Answer 1

Termination of spinal cord

Question 2

Cauda Equina

Answer 2

Inferior to conus medullaris
Downward bundle of spinal nerves which eventually exit inferiorly to corresponding vertebral segment

Question 3

Filum terminale

Answer 3

Modification of pia mater
Fibrous tissue extending from CONUS MEDULLARIS to the COCCYX

Question 4

Processes of vertebrae

Answer 4

Spinous - attachment of muscle and ligaments
Transverse - attachment of ribs

Question 5

Intervertebral foramen?

Answer 5

Formed by superior vertebral and inferior vertebral notch of adjacent vertebra

Spinal nerves enter and exit here

Question 6

Appearance of cervical vertebra

Answer 6

Large amount of white matter
Enlarged ventral horns
Largest section of spinal cord

Question 7

Appearance of thoracic vertebra

Answer 7

Largest amount of white matter
Lateral horn present from T1-L2

Question 8

Appearance of lumbar vertebra

Answer 8

Ventral horn enlarged
Broader dorsal horn than cervical
Large amounts of grey matter

Question 9

Appearance of sacral

Answer 9

Lots of grey matter. Little white.

Question 10

Two enlargements in spinal cord

Answer 10

1. Cervical enlargement - origin of brachial plexus
2. Lumbar enlargement - origin of umbra an sacral plexus

Question 11

Ascending tracts

Answer 11

Sensory info from body to brain via DORSAL HORN

Question 12

Descending tracts?

Answer 12

Motor info effectors via VENTRAL HORN

Question 13

How many vertebra?

Answer 13

33
7 cervical
12 thoracic
5 lumbar
5 fused sacral
4 fused coccyx

Question 14

How many pairs of spinal nerves

Answer 14

31

8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal

Question 15

Where is conus medullaris?

Answer 15

L1-L2 VERTEBRAE

Question 16

Dorsal root

Answer 16

Ascending tract
Sensory info
Afferent fibres

Question 17

Ventral root

Answer 17

Descending tract
Motor info
Efferent fibres

Question 18

What are rami?

Answer 18

Each spinal nerve divides into dorsal/ ventral/ meningeal rami

Question 19

Dorsal rami?

Answer 19

carries autonomic efferent, somatic efferent & afferent neurones
to and from the skin and deep muscles of back

Question 20

Ventral rami?

Answer 20

carriers autonomic efferent, somatic efferent & afferent
neurones to and from the antero-lateral part of the torso and the upper and lower limbs

Question 21

Meningeal rami?

Answer 21

re-enters via the intervertebral foramen - afferent neurones
supply ligaments, dura matter, BVs, IV discs, facet joints & periosteum of the vertebrae

Question 22

Myotome?

Answer 22

Group of muscles innervated by a single spinal nerve root

Question 23

Dermatome?

Answer 23

Area of skin hat is supplied by a single spinal nerve

Question 24

Clinical significance of dermatome

Answer 24

Symptoms that follow a dermatome, such as pain or a rash, may indicate a pathology that involves the related nerve root.

Question 25

What is a plexus?

Answer 25

Network of interconnecting nerves formed from ventral rami of multiple spinal nerves
Contain fibres from various spinal nerves which carried together to same target location

Question 26

Major plexuses? 3

Answer 26

1. Cervical
2. Brachial
3. Lumbar and sacral

Question 27

Brachial plexus?

Answer 27

The brachial plexus supplies the skin and musculature of the upper limb.

Plexus is formed by the ventral rami of C5, C6, C7, C8 and T1.

The brachial plexus is divided into five parts; roots, trunks, divisions, cords and
branches (a good mnemonic for this is Read That Damn Cadaver Book).