Week 2: Station 5 - Sections of Spinal Cord

Question 1

Which part of the spinal cord is this from?

Answer 1

Thoracic

• Thin grey and white matter area
• Long dorsal horn

Question 2

What part of the spinal cord is this from?

Answer 2

Cervical

• Note the cervical enlargement of grey matter BUT
• Large amount of white matter too

Question 3

What part of the spinal cord is this from?

Answer 3

Lumbar

• Note the enlarged grey matter from the lumbar enlargement
• Much more grey matter than white matter

Question 4

Question 5

What causes the enlargement of the grey areas in the dorsal horns of the cervical and lumbar areas?

Answer 5

• Limbs
• Dorsal horns are motor fibres

Question 6

What does the dorsal column medial lemnisal pathway carry?

Answer 6

• Fine touch
• Vibration sense
• Proprioreception

Question 7

How many neurones are there in a pathway in the dorsal medial lemniscus pathway?

Answer 7

3

First order

Second order

Third order

Question 8

Where do first order neurones from the upper limb travel in the dorsal medial lemniscus pathway?

Answer 8

The fasciculus cuneatus

Question 9

Where do signals from the first order neurones of the upper limb synapse?

Answer 9

Nucleus cuneatus

Question 10

Where do first order neurone signals from the lower limb travel in the dorsal medial lemniscus column?

Answer 10

Fasciculus gracillis

Question 11

Where do signals from the first order neurones of the lower limb synapse?

Answer 11

Nucleus gracillis

Question 12

What is the pathway of second order neurones in the dorsal column medial lemniscus pathway?

Answer 12

Arise in nucleus gracillis and nucleus cuneate

• Decussate in the medulla
• Travel up in the controlateral medial lemniscus
• They synapse in the posterolateral nuclei in the thalamus

Question 13

Where do third order neurones travel in the DCML?

Answer 13

• arise in posterolateral nuclei of the thalamus
• Travel to the ipsilateral primary somatosensory cortex through the internal capsule to form the sensory homunculus
• Remember they have already crossed over

Question 14

Summary of DCML tract

Question 15

What fibres travel in the antermedial spinothalamic tract?

Answer 15

Sensory

• Crude touch
• Pressure

Question 16

What fibres travel in the lateral spinothalamic tracts?

Answer 16

Pain

Temperature

Question 17

Where do first order neurones travel in the anterior and lateral spinothalamic tracts?

Answer 17

From the area of sensation

• Enter the dorsal horn and synapse in the substantia gelatinosa

Question 18

What happens to the second order neurones in the medial and lateral spinothalamic tracts?

Answer 18

arise from substantia gelatinosa

CROSS OVER at the level of entry

Ascend all the way up to the thalamus where they synapse

Question 19

Course of 3rd order neurones in spinothalamic tracts?

Answer 19

Thalamus to sensory cortex through the internal capsule

Question 20

Summary of spinothalamic tracts