spinal cord function/dysfunction

Question 1

what is rams

Answer 1

Inanatomy, a branch, such as a branch of a blood vessel or nerve

Question 2

what are ascending and descending tracts defined as

Answer 2

Ascending tract – sending info/impulses TO THE BRAIN

Descending tract – sending info/impulses FROM THE BRAIN

Question 3

what are layers of meninges

Answer 3

3 layers:
Tough, outer dura mater
Delicate, thin, middle layer: arachnoid mater
Very thin, inner layer, which closely follows brain surface: pia mater

Question 4

what are the layers of dura matter in brain

Answer 4

2 layers in the brain
Outer periosteal layer
Inner meningeal layer

Question 5

where do layers of dura separate in brain

Answer 5

Dural partitions

Intradural venous sinuses

Question 6

what similarities do spinal and brain meninges have

Answer 6

3 layers; outer dura, middle arachnoid, then a sub-arachnoid space containing CSF, finally pia

Question 7

what differences do spinal and brain meninges have

Answer 7

Only one layer of dura – continuous with the inner meningeal layer of dura at the foramen magnum.

Denticulate ligaments– triangular-shaped extensions of pia which stretch across the sub-arachnoid space
anchoring the cord within the vertebral foramen

Epidural space exists – containing fat and venous plexi.

Question 8

when do meninges end

Answer 8

Spinal cord ends at L2. This is the conus medullaris

Subarachnoid space ends at S2 – so arachnoid and pia mater end at S2

Question 9

where do nerve roots end

Answer 9

The nerve roots continue past meninges. These are named the cauda equina

Question 10

where does Pia end

Answer 10

Pia continues and is anchored to coccyx by the filum terminale

Question 11

where is lumbar puncture performed and what’s it used for

Answer 11

A lumbar puncture is performed after L2

Why perform a lumbar puncture?
Diagnosis
Drug administration

Question 12

In what situation would you avoid a lumbar puncture

Answer 12

in the presence of raised ICP. Why?

Because of coning of the cerebellar tonsils (tonsillar herniation)

Question 13

what are names and locations of enlargements of the spinal cord

Answer 13

There are 2 enlargements to the spinal column
C5-T1: Cervical enlargement – Brachial plexus
L1-S3: Lumbosacral enlargement – LS plexus

Question 14

how does relationship of nerve to vertebrae change down the spinal cord

Answer 14

First 7 nerves in cervical column originate above the vertebrae.
From C8 downwards nerves originate below the vertebrae (C8 nerve origin belowC7)

Question 15

in what level of the spinal cord do vertebrae number and nerve number nit match

Answer 15

Cervical (7 vertebrae, 8 nerves)

Coccygeal (4/5 vertebrae, 1 nerve)

Question 16

what is shape and parts of grey matter in spinal cord

Answer 16

Grey matter is ‘H’ shaped:
Anterior Horn
Dorsal Horn
Intermediate Horn

Question 17

what’s in grey and white matter

Answer 17

Grey matter is where the cell bodies are; white matter is where the axons are

Question 18

what are functions and origins of each part of grey matter

Answer 18

Anterior horn
Cell bodies of the motor neurones
Develops from the basal plate

Dorsal horn
Cell bodies of sensory neurones/ interneurons
Develops from the alar plate

Intermediate horn
Cell bodies of the preganglionic sympathetic neurones
Thoraco-lumbar region of the spinal cord

Question 19

what are 2 major pathways in somatic sensory perception

Answer 19

Dorsal columns-medial lemniscal pathway

Spinothalamic

Question 20

Where do neurones from upper and lower limb synapse

Answer 20

Neurones from the upper limb synapse ascend in the cuneate fasciculus
Neurones from the lower limb ascend in the gracile fasciculus

Question 21

what are 2 neurone types which exit via ventral root

Answer 21

Somatic and autonomic motor neurones

Question 22

where do sympathetic nerves originate from

Answer 22

The intermediate horn

Question 23

what are the two orders of neurones in the corticospinal tract

Answer 23

Upper motor neurone
Cell body in the motor cortex in lamina V
Axons travel in the lateral and ventral corticospinal tracts to synapse with LMN.

Lower motor neurone
Cell body in the ventral horn
Axon travels out of the ventral root to effector

Question 24

describe in detail path of UMNs

Answer 24

UMNs start in the motor cortex:
Pass through the corona radiata
Through the internal capsule
Through the peduncles at the midbrain
To the medullary pyramids
Here, 80% of the UMNs decussate

Question 25

what is the difference between anterior and lateral corticospinal tract

Answer 25

The anterior tract is for axial UMNs
Axial: the muscles of the back and spine
Ie, UMNs supplying information to LMNs which will go on to innervate axial muscles

The lateral tract is for appendicular UMNs
Appendicular: Muscles of the limbs

Question 26

what does the result of lesion in spinal cord depend on

Answer 26

Vertical level
The higher the lesion the more severe the disability
Transverse plane

Complete or partial section; damage to white matter is usually more important because ascending/ descending tracts affected

Loss of neural tissue
If due to trauma, usually small
Metastasis or degenerative diseases large effects

Question 27

Damage to the dorsal columns-medial lemniscus pathway results in

Answer 27

Loss of discriminative touch and conscious proprioception ipsilateral below the level of the lesion

Question 28

Damage to the spinothalamic tract results in:

Answer 28

Loss of temperature, pain and blunt touch contralaterally below the level of the lesion

Question 29

Damage to the corticospinal tract results in:

Answer 29

UMN lesions signs ipsilaterally

Paralysis:
Stage 1: flaccid paralysis
Stage 2: rigid paralysis

Question 30

what is flaccid paralysis

Answer 30

Spinal shock: loss of reflex activity below the lesion, lasting for days or weeks

Question 31

what is rigid paralysis

Answer 31

Return of reflexes: hyperreflexia and/or spasticity

Question 32

what does hemisection of spinal cord result in

Answer 32

Hemisection of the spinal cord results in the distinctive syndrome of ipsilateral paralysis and contralateral pain and temperature loss below the level of the lesion,

known as the Brown-Séquard syndrome.