Spinal Cord

Question 1

What are the sensory paths called?

Answer 1

Dorsal column= Gracile fasciculus and cuneate fasciculus

Spinocerebellar tracts= anterior and posterior spinocerebellar tracts

Spinothalamic= anterior and lateral tracts

Question 2

What are the motor pathways called?

Answer 2

Pyramidal tracts = anterior and lateral corticospinal tracts

Extrapyramidal tracts=
Vestibulospinal 
Rubrospinal
Reticulospinal 
Olivospinal

Question 3

Dorsal columns

Answer 3

Carry sensory information up spinal cord to sensory cortex at front of parietal lobe

Question 4

Spinocerebellar

Answer 4

Anterior and posterior, sensory info goes through lateral spinal cord to the cerebellum

Question 5

Spinothalamic

Answer 5

Anterior and lateral carries sensory info up anterolateral side spinal cord to thalamus.

Question 6

Pyramidal tracts

Answer 6

Lateral and anterior corticospinal

Motor info from motor cortex at back of frontal lobe down anterior and lateral sides of spinal cord

Question 7

Extrapyramidal tracts

Answer 7

Rubrospinal- Red nucleus in brain stem and transmits info down spinal cord

Reticulospinal- Reticular formation in brain stem down spinal cord

Vestibulospinal- vestibular formation I’m brain stem and down spinal cord

Question 8

DORSAL COLUMNS DETAIL

Answer 8

Made of gracile fasciculus and cuneate fasciculus

Carries sensory info from skin receptors (touch), joint and muscle receptors (position sense, weight discrimination , vibration etc).

It’s pathway:
A first order neurone brings sensory information from receptors

Synapses with second neurone at spinal cord

Second order neurone goes up to medulla, crosses contralaterally then to the thalamus

Synapses with third neurone at thalamus and this goes to sensory cortex at front of parietal lobe

This is a crossed tract

Question 9

Spinothalamic tract

Answer 9

Anterior and lateral spinothalamic

Lateral spinothalamic - pain and temp

Anterior spinothalamic- itch, tickle, pressure, vibrations, crude sensations

Pathway:
First order neurone brings info from sensory receptor and synapses immediately at spinal cord

Second order neurone crossses spinal cord and up to thalamus

Synapses with third neurone at thalamus

Third neurone goes up to sensory cortex at front of parietal lobe

Question 10

Spinocerebellar tract

Answer 10

Spinal cord to cerebellum

Anterior and posterior spinocerebellar tracts

Posterior spinocerebellar = Fibres do not cross at all. Enters the cerebellum via inferior cerebellum peduncle.

Anterior spinocerebellar= Most fibres cross at spinal cord entry level then cross back before entering superior cerebellar peduncle. Ones that do not cross rise ipsilaterally into superior cerebellar peduncle.

UNCROSSED PATHS

Question 11

Corticospinal tracts

Answer 11

anterior and lateral corticospinal tracts

From motor cortex and down spinal cord anteriorly and laterally.

Lateral corticospinal tract- info to control extremities like muscles. Involved in fine motor movements.

Anterior corticospinal tract- info for control of muscles in axial skeleton

So technically lateral corticospinal controls appendicular muscles and anterior corticospinal controls axial muscles

Pathway:
Cell bodies in pre and motor cortexes and axons down spinal cord

Axons descend ipsilaterally at cerebellar peduncle + become axon bundles at medulla

80-90% fibres cross to contra lateral side of medulla and descend down lateral corticospinal tract in spinal cord

10-20% descend down anterior corticospinal tract and cross over at respective spinal cord level

SO CROSSED TRACT

Question 12

Reticulospinal tract detail

Answer 12

Lateral and medial reticulospinal tract

From reticular formation of brain stem down spinal cord

Lateral reticulospinal tract= facilitates flexor reflexes and inhibits extensors

Medial reticulospinal tract= facilitates extensor reflexes and inhibits flexor reflexes

Question 13

Vestibulospinal tract

Answer 13

Vestibular nucleus of brain stem down spinal cord

Controls head and neck, axial skeleton and extremities
MODULATION of reflex activities and balance

Uncrossed tract

Question 14

Tectospinal tract

Answer 14

Superior colliculus of brain stem

Provides control of muscles in response to visual stimuli

Question 15

Rubrospinal tract

Answer 15

Red nucleus of midbrain down spinal cord

Fine motor control movements
Some of the fastest conducting fibres (120m/s)

Question 16

Spinal lesion

Answer 16

Impairs motor, sensory and autonomic functions

84% spinal lesions are traumatic

Causes of non-traumatic lesions:
(Don’t see the idea very delicately)

Degenerative disc disease and spinal canal stenosis 
Spinal infarct 
Tumour 
Inflammation of spinal cord 
Viral infection 
Development / congenital disorders

Question 17

What are proportions for traumatic spinal cord lesions

Answer 17

45% road traffic

34% industrial or domestic injuries

15% sports injuries

6% self harm

Question 18

Vulnerable vertebrae

Answer 18

Cervical spine (C5-C7) is 55% all spinal cord injuries. Can usual,t manage in electric wheelchair and help to change positions. 
If above C3/C4, needs ventilation. 

Thoracolumbar typically T12- if incomplete, patient can do some movements

Mid thoracic (T4-T7)

Most traumatic cases = due to fracture dislocation of vertebrae and compresses spinal cord

Sympathetic NS from thoracic and lumbar
Parasympathetic NS from cervical and sacral areas

Question 19

Tetraplegia / quadriplegia

Answer 19

Impairment or loss of motor and sensory function in cervical segments of spinal cord.

Affects all 4 limbs

Question 20

Paraplegia

Answer 20

Impairment or loss of sensory and motor functions of thoracic, lumbar and sacral segments of spinal cord.

Trunk, legs and pelvis may be involved

Question 21

Complete vs incomplete spinal cord lesions

Answer 21

Complete = Total loss of function below point of injury - no sensory info into spinal cord and no motor information out of spinal cord
Outcome more predictable

Incomplete= Some sparing of neural material below the level of lesion (some sensory and motor info).
55-65% of spinal cord lesions.
Outcome less predictable

Example: lesion in cervical spine but still have sensation In bowel and bladder would be incomplete tetraplegia