Spinal Cord Function and Dysfunction Flashcards
how many spinal segments
31
how many spinal nerves
31
number of nerves from each segment of the spinal cord?
8 cervical 12 thoracic 5 lumbar 5 sacral 1 coccygeal
How many lumbar vertebrae
5
How many cervical vertebrae
7
How many sacral vertebrae
5
How many coccygeal vertebrae
1
Nerves leave the vertebral column through ….
INTERVERTEBRAL FORAMINA
There are 2 enlargements in the spinal cord for what reason
Innervation of the limbs
Where are the 2 enlargements of the spinal cord
Cervical (C3-T1) enlargement
Lumbar (L1-S3) enlargement
Which vertebrae is the cervical enlargement
C3-T1)
Which vertebrae is the lumbar enlargement
L1-S3
At some point in development, growth of the vertebral column is faster than that of the spinal cord, so the further down the vertebral column you go, what happens?
the further the nerves have to travel downwards to find their respective foramina
What vertebral level does the spinal cord end
L2
What is either side of the epidural space
Dura and vertebral periosteum
Layers of the meninges, out to in?
DAP - dura, arachnoid, pia
Pia is the Xmost layer of the meninges
Innermost
Pia mater adheres tightly to the …
Spinal cord
Arachnoid mater is ballooned up against the …
Dura mater
What is either side of the subarachnoid space
The arachnoid and Pia mater
Epidural nerve block is between what vertebral levels?
L4 and L5
Spinal nerve block is between what vertebral levels? What space is the anaesthetic infected into
between L3 and L4, subarachnoid
Grey matter in the spinal cord contains…
Cell bodies
Spinal matter in the spinal cord contains…
Axon tracts
DERMATOME is defined as:
AREA OF SKIN INNERVATED BY ONE SINGLE SPINAL NERVE OR SPINAL SEGMENT
Muscle nerve fibres will come out of which root of the spinal cord
Anterior
What travels through the dorsal horns of the spinal cord and in what direction
into these go the sensory nerves
What travels through the ventral horns of the spinal cord and in what direction
out of these go the motor neurones
Where is the sulcus in the spinal cord found
Posterolaterally
Where is the fissure found in the spinal cord
Anterolaterally
What type of nerve fibres are in the fasciculus gracilis tract in the spinal cord
Sensory (fine touch, vibration, proprioception) from ipsilateral lower limb
What type of nerve fibres are in the fasciculus cuneatus tract in the spinal cord
Sensory (fine touch, vibration, proprioception) from ipsilateral upper limb
What type of nerve fibres are in the spinocerebellar tract in the spinal cord
Proprioception from limbs to cerebellum
What type of nerve fibres are in the lateral corticospinal tract in the spinal cord
Motor to ipsilateral anterior horn
What type of nerve fibres are in the spinothalamic tract in the spinal cord
Pain temperature fibres from contralateral side of the body
What type of nerve fibres are in the anterior corticospinal tract in the spinal cord
Motor to ipsi and contralateral anterior horn
What happens to nerve fibres in the anterior white commissure in the spinal cord (2)
Pain and temperature fibres and anterior corticospinal tract fibres cross
Which is more medial, fasciculus cuneatus or fasciculus gracilis in the spinal cord
Gracilis
Which is more lateral, fasciculus cuneatus or fasciculus gracilis in the spinal cord
Cuneatus
What tract has fibres: Motor to ipsi and contralateral anterior horn
anterior corticospinal tract
What tract has fibres: Pain temperature fibres from contralateral side of the body
Spinothalamic
What tract has fibres: Motor to ipsilateral anterior horn
Lateral coricospical tract
What tract has fibres: Proprioception from limbs to cerebellum
spinocerebellar
What tract has fibres: Sensory (fine touch, vibration, proprioception) from ipsilateral upper limb
Fasciculus cuneatus
What tract has fibres: Sensory (fine touch, vibration, proprioception) from ipsilateral lower limb
Fasciculus gracilis
CORTICOSPINAL TRACT is the main descending tract for…
Voluntary movement
Main descending pathway for voluntary movement is the …
corticospinal tract
Main sensory pathway for pain/temp is the …
spinothalamic tract
spinothalamic tract is the Main sensory pathway for …
for pain/temp
Dorsal column pathways are the main sensory pathways for ….
touch/proprioception
Sensory system is generally composed of how many neurones
3
What are the 3 neurones in the sensory system
Skin-> spinal cord/medulla
spinal cord/medulla -> thalamus
thalamus -> cortex
Where do dorsal column sensory neurons cross?
After primary neurone synapses with the secondary spinal cord neurone
Where do spinothalamic primary neurons synapse
In the spinal cord the same vertebral level they enter
Where do fasciculus cuneatus/gracilis (dorsal column) primary neurons synapse
Medulla
Secondary neurones tend to become/stay contra or ipsilateral?
Become contralateral
Spasticity is a heightened XX in someone with injury to the Y
XX - reflex pathway
Y - brain
Describe a reflex pathway starting from muscle sensory nerve sensing stretching? (In which way is
muscle sensory nerve senses stretching -> nerve sends signal to the spinal cord where it synapses directly on alpha motor neuron in the anterior horn and an inhibitory interneuron -> alpha motor neuron to the extensor excites, and inhibitory interneuron inhibits antagonist muscle neuron
Describe the corticospinal tract for voluntary movement
voluntary movement will start in the motor cortex. Single neuron in the brain synapses a single neuron in the ventral horn of the spinal cord where it then goes out the ventral root to find its muscle ting.
could also cross over at the medulla
Thoracolumbar is X outflow.
sympathetic
Craniosacral is X outflow.
parasympathetic
FACTORS AFFECTING SEVERITY OF SPINAL LESION: (3)
- Amount of loss of neural tissue
- Vertical level (higher = more serious)
- Transverse plane (how much of the cord is damaged- more tracts = more deficits)
Ways of LOSS OF NEURAL TISSUE: (3)
trauma
metastases
degenerative disease
Most common spinal injuries?
Broken neck/back
Most common cause of spinal injury
road traffic accidents, accidents during sports or recreation or falls (in older people)
2 stages of injury to the lateral corticospinal tract? What type of paralysis in each stage?
1: spinal shock: loss of reflex activity below the lesion lasting for days/weeks = flaccid paralysis
2: return of reflexes: hyperreflexia and/or spasticity =. rigid paralysis
explain Brown-Sequard syndrome?
XXXX
