Motor pathways

Question 1

Lateral Corticospinal - function

Answer 1

Upper and lower limb voluntary control

Question 2

Anterior corticospinal - function

Answer 2

Axial and trunk muscle voluntary control

Question 3

Lateral corticospinal - pathway

Answer 3

Originates in the motor cortex
Comprises 90% of corticospinal fibres
Decussate at the pyramidal decussation
Descend in the lateral funiculus
Terminates at C5-T1 and L1-S3 spinal levels
Target alpha motoneurons in lateral motoneuron pools

Question 4

Anterior corticospinal -pathway

Answer 4

Originates in the motor cortex
Comprises 10% pf corticospinal fibres
Do not decussate at pyramidal decussation
Descend in anterior funiculus
Decussate at different spinal cord levels
Terminate at C1-C4 and T2-T12 spinal cord levels
Target alpha motoneurons in medial motoneuron pools

Question 5

Rubrospinal - function

Answer 5

Regulate muscle tone of flexor muscles of the contralateral upper limb

Question 6

Rubrospinal - pathway

Answer 6

Originates in red nucleus
Decussates at midbrain
Descends through lateral funiculus
Projects to interneurons in cervical spinal cord

Question 7

Tectospinal - function

Answer 7

Innervates the neck muscles that move the head to position the visual axis in response to external stimuli

Question 8

Tectospinal - pathway

Answer 8

Originates in the superior colliculus
Decussates at the midbrain
Descends through the anterior funiculus
Terminates at the cervical spinal cord

Question 9

Reticulospinal - function

Answer 9

Initiates locomotion and maintains upright body posture

Question 10

Reticulospinal - pathway

Answer 10

Originates in caudal pontine and rostral medullary reticular formations
Some fibres decussate in the anterior white commissure of the spinal cord
Descends in the anterior funiculus
Terminates at all spinal cord levels

Question 11

Lateral vestibulospinal - function

Answer 11

Generates muscle tone in deep back and limb extensors in response to gravity

Question 12

Lateral vestibulospinal - pathway

Answer 12

Originates in the lateral vestibular nuclei at the junction between the pons and medulla
Stay ipsilateral
Descends in anterior funiculus
Terminates at all levels of the spinal cord

Question 13

Medial vestibulospinal - function

Answer 13

Keeps the head upright and stabilises head during movement

Coordinates head and eye movements

Question 14

Medial vestibulospinal - pathway

Answer 14

Originates in the medial vestibular nuclei in the medulla
Some fibres decussate via the anterior white commissure
Terminates at cervical spinal cord segments