THE SPINAL CHORD

Question 1

How many of each vertebrae is there?

Answer 1

8 cervical
12 thoracic
5 lumbar 
5 sacral
1 coccygeal

Question 2

give the three layers of meninges starting at the innermost layer

Answer 2

pia mater
arachnoid mater
dura mater

Question 3

what tract does discriminative touch and proprioception use?

Answer 3

dorsal columns
sensory from ipsilateral lower limbs- fasciculus gracilis
sensory from ipsilateral upper limbs- fasciculus cuteatus

Question 4

what tract does pain and temperature use?

Answer 4

spinothalamic tract

Question 5

describe the spinothalamic pathway

what is it for?

Answer 5

Pain and temperature

sensory neurones from the stimulus synapse in the spinal ganglion
the sensory neurone enters the dorsal horn and may travel 1-2 levels of the lissaeur tract before synapsing in the nucleus proprius and crossing over
the secondary neurone travels up the spinal chord on the contralateral side, passing through the medulla
it then synapses in the thalamus and the tertiary neurone travels tot the cerebral cortex.

Question 6

describe the dorsal horn pathway

what is it for?

Answer 6

touch discrimination, proprioception and vibration

sensory neurones enter the dorsal horn in the spinal column
the neurone does not synapse and travels up the ipsilateral side of the spinal chord to the medulla
the neurone synapses in the medulla to the secondary neurone which crosses over to the contralateral side of the spinal chord
the neurone travels up to the thalamus where it synapses for a second time and the tertiary neurone travels to the cerebral cortex

Question 7

at what level does the spinal chord end?

Answer 7

L2

Question 8

what factors affect the severity of a spinal lesion?

Answer 8

vertebral level of lesion (the higher the greater the disability)
loss of neural tissue (usually more if metastases or degenerative disease)
transvers plane

Question 9

what are the two stages to paralysis is the lesion is in the corticospinal tract?

Answer 9

STAGE 1: loss of reflexes below the lesion. weeks/months. flaccid paralysis

STAGE 2: return of reflexes. hyperrexlexia and/or spasticity. rigid paralysis