Week 3 content

Question 1

what are the spinal cord regions

Answer 1

lumbar-sacral plexus and sacral plexus.

Question 2

what is the function of the fillium terminale

Answer 2

the fillium terminale is a fibrous band that extends down the posterior side of the spinal cord that functions to stabilize the distal spinal cord during cephalic and causal traction by making sure it stays taut.

Question 3

what is the function of the cauda equina

Answer 3

the bundle of nerve roots located at the lower end of the spinal cord (horsetail that comes after the spinal cord has ended).

function - send and receive messages to and from the lower limbs and pelvic organs.

Question 4

what is the function of the conus medullaris

Answer 4

This structure serves to stabilize the spinal cord by connecting the conus to the coccyx via the coccygeal ligament

he conus medullaris is the bundled, tapered end of the spinal cord nerves

Question 5

what is the function of the ventral, dorsal and lateral horn

Answer 5

grey areas

dorsal horn - processes sensory information.
lateral horn - processes autonomic information (sympathetic T1-L2 and parasympathetic S2-S4 spinal cord segments)
ventral horn - processes motor information.

Question 6

what is the function of the ventral, dorsal and lateral columns

Answer 6

white areas

dorsal column - medial lemniscus system - sacral, lumbar, lower, thoracic, upper thoracic and cervical.

lateral column - lateral corticospinal tract and rubrospinal tract (voluntary)

medial - reticulospinal tract to postural motor neurons, reticulospinal tract to SPG and limb motor neruons, vestibulospinal and medial corticospinal.

Question 7

where does the spinal cord terminate ?

Answer 7

L1/L2 level

Question 8

what are the three layers of meninges

Answer 8

dura mater (outmost)
arachnoid (middle layer)
pia mater (innermost)

Question 9

what are the differences in the spinal cord regions?

Answer 9

cervical - large amount of white matter (because white matter carries sensory info to brain, therefore makes sense that more sensory tracts closer to the brain) and anterior horn at ventral is large.

sacral - white matter is smaller.

thoracic - lateral horn, not as large anterior grey horn.

lumbar - anterior horn is a bit larger.

Question 10

which spinal nerves are sympathetic and parasympathetic

Answer 10

T1-L2 spinal nerves contain sympathetic NS axons.

S2-S4 contain spinal nerves parasympathetic NS axons.

Question 11

what does the dorsal rami contain

Answer 11

sensory and motor axos that innervate deep back muscles, zygopoyseal joints and overlying back skin.

Question 12

what does the ventral rami contain

Answer 12

contain sensory and motor axons that innervate all plexi and trunk overlying skin.

Question 13

what is a paraplegic

Answer 13

patients with thoracic paraplegia will have full upper body movement, with varying degrees of trunk paralysis and complete lower limb paralysis.

Question 14

define quadriplegic or tetraplegia

Answer 14

injury of cervical cord results in quadriplegia.
C1-C3 - paralysis of diaphragm and respiratory muscles.

C5 - strength of deltoid and biceps.

C7 - strength of triceps, wrist flexors and extensors.

Question 15

define anesthesia and analgesia

and paralysis and paresis

Answer 15

anesthesia - loss of all forms of sensation
analgesia - inability to feel pain

paralysis - loss of ability to move
paresis - partial loss of voluntary mvoeemnt.

Question 16

segmental lesion vs vertical lesion

Answer 16

segmental nerve lesion occurs at the horn, root or spinal nerve and may result in
- altered or lost sensation in a dermatome at that level.
- decreased or lost muscle power in a myotome at that level.
- decreased or lost stretch reflex.

vertical tract lesion occurs in the spinal cord vertical tracts and may result in
- altered or lost sensation below the level of that lesion.
- motor tract signs including decrease/loss of muscle power, spasticity, muscle hypertonia
- altered or lost control of BP, bladder, bowel control, thermoregulation.

Question 17

spinal cord vs peripheral lesion

Answer 17

spinal cord - causes altered/lost sensation in a dermatome at that level, decreased or lsot muscle power in a myotome at and below the level of the lesion, decreased or lost stretch reflex, altered lost control of BP, bladder and bowel control and thermoregulation.

peripheral lesion - causes altered/lost sensation in a peripheral nerve distribution, decreased/lost muscle power in the peripheral nerve distribution, no vertical tract signs, decreased or lost stretch reflex.

Question 18

how do we classify spinal cord injuries

Answer 18

complete or incomplete.

Question 19

what is the function of the meninges

Answer 19

to cover and protect the CNS
protect blood vessels on the surface of the CNS
form dural venous sinuses
Meninges provide protection to CNS, has rich blood supply, has CSF which provides nourishment and protection.

Question 20

dura mater

Answer 20

two layered sheet of fibrous connective tissue that forms dural venous sinuses (drains blood from brain and takes to blood)

Question 21

arachnoid mater

Answer 21

loose weblike covering of the brain contains projections (arachnoid granulations) that allow CSF to re-enter the circulation via dural venous sinuses.

superficial to subarachnoid space, which is deep to the arachnoid layer but superficial to the pia mater.

Question 22

pia mater (gentle mother)

Answer 22

delicate layer clinging to the brain tissue
dense rich blood supply of underlying neural tissue
located deep to subarachnoid space.

Question 23

what is the significance of the subarachnoid space

Answer 23

between the arachnoid membrane and the pia mater. It is occupied by delicate connective tissue trabeculae and intercommunicating channels containing cerebrospinal fluid (CSF) as well as branches of the arteries and veins of the brain.

Question 24

what is the significance of the subdural space

Answer 24

is a potential space that can be opened by the separation of the arachnoid mater from the dura mater as the result of trauma, pathologic process.

typically exists only under pathological conditions

Question 25

what is the signifiance of the epidural/extradural space

Answer 25

within the vertebral column and extends from the foramen magnum to the sacral hiatus

helps absorb shock, which protects the other contents in the area, as well as the dura

Question 26

explain the ventricular system circulation

Answer 26

CSF is produced by the choroid plexus, then travels to the third ventricle, through the cerebral aqueduct to the fourth ventricle (where some goes into the spinal cord), majority drains into the median aperture. It is then circulated back up to the arachnoid layer and is pushed into the dura venous sinus.

→ Arachnoid granulations are essential for the drainage of CSF.
→ If somewhere along the circulation pathway there is an impingement, CSF is not drained properly and the brain will swell up.
o This condition is called hydrocephalus – can be found in adult and children.