Lecture 18/19 Problem solving 1

Question 1

Where is dermatome C3, T4/5, T10 and L1

Answer 1

C3: neck
T4/5: nipple
T10: umbilicus
L1: inguinal ligament

Question 2

What does lesion on one side of the spinal cord cause

Answer 2

Dissociated sensory loss: discriminative sensation from one side, pain and temperature on the other lost

Question 3

What does a lesion on one side of the brain stem cause

Answer 3

Associated sensory loss: loss of discriminative and pain and temperature from the same (opposite) side

Question 4

What happens when you have a lesion to an Upper motor neuron at 3 different places along the tract

Answer 4

Spastic paralysis.

1. Before decussation at medullary pyramid : spastic paralysis opposite side of lesion
2. Top of the spinal cord (eg. C3): upper and lower body spastic paralysis, same side as lesion
3. Bottom of spinal cord (T10) lower body spastic paralysis, same side as lesion

LMN will not get information from the cortex.

• The muscle tone will be increased- increased tendon reflexes
• movements will be exaggerated/crude.
• Muscle power will be reduced- muscle wasting
• Plantar response: extensor

Question 5

What happens when you have a lesion to an Lower motor neuron - eg. trauma, polio killing them off

Answer 5

Flaccid paralysis:

• Normal or decreased tone- no more tendon reflexes
• Reduced muscle power
• Flexor plantar response

Question 6

What type of information is carried by the Dorsal spinocerebellar tract and where is it going

Answer 6

• Proprioceptive information from golgi tendon organs that stay on the same side of the body. Synpase at the DNC before continuing to the Cerebellum via inf cerebellar peduncle.
• Other fibres carrying conscious proprioceptive information to the cortex that were actually from the dorsal column pathway also run in this tract.

Question 7

How many segments of the spinal cord have to be damaged before there is an effect on LMN functioning

Answer 7

Two or 3 because 2 or 3 LMN innervate the same muscle

Question 8

Where does the spinal cord nerves end vs the bony vertebrae levels

Answer 8

The official spinal cord nerves of the adult ends at L1 level. This coincides more with the T 11 bony vertebra.

Only higher up the bony vertebrae C3 is close to the C3 nerve.

Question 9

How does loss of pain and temperature sensation affect a small band of skin (4-5 cm) around the body at the level T10?

Answer 9

Pain temperature fibres cross over at the ant white commissure: near the Central canal filled with CSF, lined by ependymal cells (which also line the ventricular system).

Rarely they form a tumour: Ependymoma which causes pressure on these crossing over fibres at the segment level it is growing