Ascending tracts

Question 1

Name the conscious ascending tracts

Answer 1

Anterolateral Spinothalamic

Dorsal column

Question 2

Name the unconscious ascending tracts

Answer 2

Spinocerebellar

Question 3

What are the modalities of the Dorsal tract?

Answer 3

Conscious proprioception

Fine touch

Question 4

What are the modalities of the Anterolateral Spinothalamic tracts?

Answer 4

Crude touch
Pain
Temperature
Pressure

Question 5

What are the modalities of the Spinocerebellar tracts?

Answer 5

Unconscious proprioception

Question 6

Which part of the Dorsal column do signals from the upper limb travel in?

Answer 6

Fasciculus cuneatus (Outer part of tract)

Question 7

Which part of the Dorsal column do signals from the lower limb travel in?

Answer 7

Fasciculus gracilis (Inner part of tract)

Question 8

Where do first order neurones of the fasciculus cuneatus synapse?

Answer 8

In the cuneate nucleus of the medulla

Question 9

Where do first order neurones of the fasciculus gracilis synapse?

Answer 9

In the gracile nucleus of the medulla

Question 10

What is the route of second order neurones in the dorsal tracts?

Answer 10

Leave nucleus in medulla
Decussate in medulla oblongata
Insert on contralateral side of the Thalamus

Question 11

What is the route of third order neurones in the dorsal tracts?

Answer 11

Leave VPL nucleus of thalamus

Enter somatosensory cortex

Question 12

Briefly, what is the route of the Dorsal tract?

Answer 12

Enter spinal cord with cell body in Dorsal root ganglion
Stay on ipsilateral side and travel up to nucleus in medulla
Synapse and decussate in medulla oblongata
Travel up to contralateral side of thalamus
Synapse and leave VPL nucleus of thalamus to go to somatosensory cortex

Question 13

What is the route of the first order neurones in the Anterolateral spinothalamic tracts?

Answer 13

Arise at receptors and rise 1-2 levels then synapse in the dorsal horn (substantia gelatinosa)

Question 14

What is the route of the second order neurons in the Anterolateral spinothalamic tracts?

Answer 14

Leave substantia gelatinosa and decussate
Split into anterior and lateral columns and ascend in the contralateral side of the spinal cord (Still run alongside each other)
Synapse in contralateral side of the thalamus

Question 15

What is the route of the third order neurones in the Anterolateral spinothalamic tracts?

Answer 15

Leave VPL nucleus in thalamus and go to somatosensory cortex

Question 16

How many neurones are in the spinocerebellar tract?

Answer 16

Two - There is no third order neurone as it does not go to the cortex!

Question 17

Where do the first order neurones of the spinocerebellar tract synpase?

Answer 17

Dependent on which fibres of the tract;

• Neurones that remain ipsilateral synapse in Clarke’s nucleus
• Neurones that decussate synapse in the Dorsal horn

Question 18

What do some fibres of the spinocerebellar tracts do?

Answer 18

Decussate twice - once just below the cerebellum (Superior cerebellar peduncle) and then again in the cerebellum

Question 19

All fibres of the spinocerebellar tract insert into the cerebellum on the ipsilateral side. True/False?

Answer 19

True

Some remain ipsilateral the whole time, other decussate but then decussate again so end up ipsilateral.

Question 20

What can cause a lesion in the spinal cord of the Dorsal column tract?

Answer 20

Vitamin B12 deficiency
Tabes Dorsalis (Neurological issue seen in late stage syphillis)

Question 21

What pattern of sensory loss will be seen with a lesion in the spinal cord of the Dorsal column tract?

Answer 21

Ipsilateral loss of conscious proprioception and fine touch (As decussation in medulla oblongata)

Question 22

What is the pattern of sensory loss if damage to the Anterolateral Spinothalamic tract occurs?

Answer 22

Contralateral loss of pain and temperature as well as crude touch and pressure (As decussate in the spinal cord)

Question 23

What is the injury in Brown-Séquard syndrome?

Answer 23

Hemisection of the spinal cord (One sided lesion) affecting the Dorsal column tract and the Anterolateral Spinothalamic tract. Most often due to trauma

Question 24

What is the pattern of sensory loss in Brown-Séquard syndrome?

Answer 24

Ipsilateral loss of fine touch and conscious proprioception (As dorsal column tract damaged)
Contralateral loss of pain and temperature (As Anterolateral Spinothalamic tract damaged)
Will also have damage to the descending tracts causing ipsilateral hemiparesis

Question 25

What is the defect when damage to the Spinocerebellar tract occurs?

Answer 25

Ipsilateral loss of muscle co-ordination (due to loss of unconscious proprioception)
Rarely occurs in isolation, usually involes the descending tracts so may have muscle weakness/paralysis