spinal cord tracts

Question 1

What sensory modalities are carried by the dorsal column-medial lemniscus pathway?

Answer 1

fine touch, vibration and proprioception

Question 2

In which tract do upper limb fine touch, vibration and proprioception fibres travel in?

Answer 2

cuneate fasciculus of dorsal columns

Question 3

in which tract to lower limb fine touch, vibration and proprioception fibres travel in?

Answer 3

gracile fasciculus of dorsal column

Question 4

where do the dorsal column fibres decussate?

Answer 4

medulla

Question 5

describe the levels of first order, second order and third order neurones of the dorsal column-medial lemniscus pathway

Answer 5

1st order: carry information from spinal cord to medulla
2nd order: carry info from medulla (specifically the gracile and cuneate nuclei) to the thalamus
3rd order: thalamus to the primary sensory cortex of the brain (post-central gyrus)

Question 6

What does the spinothalamic tract carry?

Answer 6

crude touch, pressure, pain and temperature

Question 7

Where do spinothalamic fibres decussate?

Answer 7

In the spinal cord, 1-2 levels up or down from the level of entry of the fibres

Question 8

Describe the levels of the 1st, 2nd and 3rd order neurons

Answer 8

1st order: sensory receptors from the periphery enter the spinal cord, travel up or down 1-2 levels and synapse in the substantial gelatinosa of the dorsal horn
2nd order: from substantial gelatinosa, decussate and travel to the thalamus
3rd order: thalamus to primary sensory cortex