Tracts

Question 1

What are the descending pyramidal tracts

Answer 1

corticospinal and corticobulbar

Question 2

What type of tract is the corticospinal tract

Answer 2

Descending motor pyramidal tract

Question 3

What does the corticospinal tract do

Answer 3

Conscious motor control of skeletal muscles

Question 4

What are the two parts of the corticospinal tract and what is their function

Answer 4

Lateral = limb control 
Anterior = axil muscle control

Question 5

What is the pathway of the corticospinal tract

Answer 5

From the pyramidal cells of the cerebral cortex, through the posterior limb of the internal capsule, through the cerebral peduncle, to the brainstem and anterior medulla, form medullary pyramids, decussation of the pyramids, form lateral and anterior tracts down to spinal cord

Question 6

Where does the corticospinal tract decussate

Answer 6

85% in the medulla (lateral)

15% remain ipsilateral until reach white matter of spinal cord at the level of exit (anterior)

Question 7

What happens if there is damage to the corticospinal tract

Answer 7

Contralateral symptoms

Upper motor neuron syndrome

• Hypertonia
• Hyperreflexia
• Clonus
• Babinski sign
• Muscle weakness

Question 8

What type of tract is the corticobulbar tract

Answer 8

Descending motor pyramidal tract

Question 9

What does the corticobulbar tract do

Answer 9

Movement of muscles of the head 
Swallowing 
Phonation 
Movements of tongue 
Facial expression

Question 10

What does the corticobulbar tract do in terms of decussation

Answer 10

Most don’t decussate (remain ipsilateral)
Except the hypoglossal nerve
And the facial nerve that supplies the lower half of the face

Question 11

Which nuclei does the corticobulbar tract supply

Answer 11

Trigeminal
Facial 
Vagus 
Accessory 
Hypoglossal

Question 12

What happens if the corticobulbar tract is damaged

Answer 12

If unilateral damage - mild muscle weakness

Hypoglossal - spastic paralysis of contralateral tongue muscles, deviation of tongue to contralateral side

Facial - spastic paralysis of muscles of contralateral quadrant of the face (lower face)

Question 13

What is the path of the corticobulbar tract

Answer 13

From the ventral motor cortex, to the internal capsule, to the midbrain/pons/medulla

Question 14

What is the function of the extrapyramidal tracts

Answer 14

Involuntary and autonomic control of all musculature

Question 15

What is the role of the vestibulospinal tract and what is it’s pathway and is it ipsilateral/contralateral

Answer 15

Balance and coordination

From vestibular nuclei to spinal cord

Ipsilateral

Question 16

What is the role of the reticulospinal tract/ what is it’s pathway and is it ipsilateral/contralateral

Answer 16

Medial - from pons to spinal cord, contralateral, facilitates voluntary movement and increases muscle tone

Lateral - from the medulla to the spinal cord, contralateral, inhibits voluntary movement and reduces muscle tone

Question 17

What is the role of the rubrospinal tract/what is it’s pathway and is it ipsilateral/contralateral

Answer 17

Fine control of motor hand movements

red nucleus to spinal cord

contralateral

Question 18

What is the role of the tectospinal tract, what is it’s pathway and is it ipsilateral/contralateral

Answer 18

Visual reflexes

from superior colliculi of midbrain to spinal cord

contralateral

Question 19

What are the ascending sensory tracts

Answer 19

Dorsal-column medial lemniscus

Anterolateral system (spinothalamic)

spinocerebellar

Question 20

What is the function of the dorsal column tract

Answer 20

Fine touch, vibration and proprioception

Question 21

What are the two parts of the dorsal column pathway and what is their role

Answer 21

Lateral - fasciculus cuneatus = upper limb

medial - fasciculus gracilis = lower limb

Question 22

Where does the dorsal column decussate

Answer 22

Medulla

Question 23

What is the pathway of the dorsal column pathway

Answer 23

From the lower/upper limb to the nucleus gracilis/cuneatus, through the medulla (decussates), travel up as the medial lemniscus, to the thalamus, to the primary sensory cortex

Question 24

What happens if you damage the dorsal column pathway

Answer 24

Loss of fine touch, vibration and proprioception

If in spinal cord, loss is ipsilateral

Question 25

What are the two tracts of the anterolateral (spinothalamic) system and their function s

Answer 25

Anterior - crude touch and pressure

lateral - pain and temperature

Question 26

What is the pathway of the spinothalamic tracts

Answer 26

From the sensory receptors in the periphery, up 1-2 vertebral levels, synapse in the substantia gelatinosa in the top of the dorsal horn, decussate within the spinal cord, travel up as the lateral and anterior pathways to the thalamus, through the internal capsule to the primary sensory cortex

Question 27

Where do the spinothalamic tracts decussate

Answer 27

In the spinal cord

Question 28

What happens if the spinothalamic tracts are damaged

Answer 28

Contralateral loss

Brown-sequard syndrome

• Hemisection of spinal cord
• Damage to both pathways
• Damage to descending motor pathway
• Hemiparesis (motor and sensory)

Question 29

What is the function of the spinocerebellar tracts

Answer 29

Unconscious proprioceptive information from the lower limbs

Question 30

What is the pathway of the spinocerebellar tract

Answer 30

Muscles to cerebellum

Question 31

What are the 4 tracts of the spinocerebellar tract

Answer 31

• Posterior (ipsilateral)
• Anterior (ipsilateral - decussates twice)
• Cuneocerebellar (ipsilateral - decussates twice)
• Rostral (ipsilateral)

Question 32

What happens it the spinocerebellar tracts are damaged

Answer 32

Unilateral loss of muscle coordination