Supraspinal Motor Systems: Pyramidal System

Question 1

Corticalbulbar tract

Starts at _____
PRojects to ______

Answer 1

Motor cortex to cranial nerve nuclei

Question 2

Corticalspinal tract

Starts at _____
PRojects to ______

Answer 2

Motor cortex to spinal cord

Question 3

Most corticospinal/pyramidal tract originate from:

Answer 3

Primary motor cortex

Question 4

Lower limbs are in which area of motor and sensory homunculi?

A. Medial
B. Dorsal
C. Lateral
D. Rostral

Answer 4

A. Medial

Question 5

The face is in which area of motor and sensory homunculi?

A. Medial
B. Dorsal
C. Lateral
D. Rostral

Answer 5

C. Lateral

Question 6

Which corticospinal tract decussates and continues on contralateral side of body?

Answer 6

Lateral corticospinal tract

Question 7

Which corticospinal tract does not decussate and continues on ipsalateral side of body

Answer 7

Ventral/anterior corticospinal tract

Question 8

Where does lateral corticospinal tract decussate?

Answer 8

Caudal medulla

Question 9

Lateral corticospinal tract fibers that end in higher segment are typographically located:

A. Most lateral
B. Most ventral
C. Most medial
D. Most caudal

Answer 9

C. Most medial

Question 10

Lateral corticospinal tract fibers that end in lower segment are typographically located:

A. Most lateral
B. Most ventral
C. Most medial
D. Most caudal

Answer 10

A. Most lateral

Question 11

True or false: The vast majority of corticospinal fibers do NOT decussate

Answer 11

False, the vast majority DO decussate (80-90%)

Question 12

The majority (55%) of pyramidal/corticospinal fibers end in the ________ spinal cord?

A. Thoracic
B. Lumbar
C. Sacral
D. Cervical

Answer 12

D. Cervical spinal cord

Question 13

Fibers going to which body structures are typically the corticospinal fibers that directly synapse with motor neurons and do NOT synapse with interneurons first?

A. Eyes
B. Hands
C. Legs
D. Back

Answer 13

B. Hands

Question 14

In the pyramidal system

Upper motors neurons consist of __________

Lower motor neurons consist of _______

Answer 14

Upper motors neurons consist of Corticospinal tract (pyramidal cells)

Lower motor neurons consist of alpha motor neurons (ventral horn cells)

Question 15

A patient presents with loss of voluntary movements, exaggerated deep tendon reflexes, clonus, muscle spasticity, loss of speed and agility, and Positive Babinski sign. What type of lesion is most likely in this pt?

A. Upper motor corticospinal lesion
B. Lower motor neuron DCML lesion
C. Lower motor neuron corticospinal lesion
D. Both upper and lower motor corticospinal lesions

Answer 15

A. Upper motor corticospinal lesion

Abnormal activation of intact brain stem and spinal pathways

Question 16

A patient presents with loss of muscle tone, loss of deep tendon reflexes, atrophy of muscle, and loss of voluntary movement of leg muscles. What type of lesion is most likely in this pt?

A. Upper motor corticospinal lesion
B. Lower motor neuron DCML lesion
C. Lower motor neuron corticospinal lesion
D. Both upper and lower motor corticospinal lesions

Answer 16

C. Lower motor neuron corticospinal

Loss of alpha motor innervation to muscle

Question 17

What is a positive Babinski sign?

Answer 17

Stroke bottom of foot should cause plantar flexion (- Babinski)

If stroke bottom of foot and yield dorsiflexion (+ Babinski)…this is an abnormal plantar reflex and is typical of an upper motor neuron lesion in corticospinal tract

Question 18

Spasticity explanation

Answer 18

Abnormal synergy
Tying to raise arm but arm flexes in and wrist flexes

Unable to reflexively resist passive movements

Difficulty initiating and controlling muscular movements

Question 19

Patient presents with decorticate rigidity characterized by abnormally flexed upper extremities and abnormally extended lower extremities. Where is the lesion likely to be?

A. Corticospinal tract
B. Below red nucleus
C. Above red nucleus
D. Lower motor neurons

Answer 19

C. Above red nucleus

A lesion here would cause hyperactivity of red nucleus which would cause abnormal flexion of upper extremities

Question 20

Patient presents with decerebrate rigidity characterized by abnormally flexed upper extremities and abnormally extended lower extremities. Where is the lesion likely to be?

A. Corticospinal tract
B. Below red nucleus
C. Above red nucleus
D. Lower motor neurons

Answer 20

B. Below red nucleus

Lesion here would cause hyperactivity of vestibular nuclei which causes excessive extension

Question 21

In the corticobulbar tract,

Upper motor neurons are in __________

Lower motor neurons are in ________

Answer 21

Upper motor neurons are in the cerebral cortex

Lower motor neurons are in cranial nuclei

Question 22

Patient suffered from a stroke what would you typically see in this patient? What type of lesion is it?

Answer 22

Unilateral upper motor neuron lesion resulting in paralysis of muscles of facial expression in lower 1/2 of contralateral face, but ability to raise eye brows and close eye lid B/L

Question 23

Patient was diagnosed with Bell’s palsy, what would you typically see in this patient? What type of lesion is it?

Answer 23

Unilateral lower motor neuron lesion (facial n) resulting in paralysis of muscles of facial expression in ipsalateral side of face, and no ability to raise eye brows and close eye lid on ipsalateral side

Question 24

Why does stroke only have paralysis of lower contralateral face?

Answer 24

Upper face is innervated from B/L upper motor neurons. Stroke almost always affects only one side of brain…so still get innervation from other side of brain

Question 25

Why does bell-s palsy affect ipsalateral upper and lower face?

Answer 25

Lower motor neuron (facial n) lesion affects motor neurons after decussation. Facial nerve innerv upper and lower ipsalateral face

Question 26

Bell’s palsy and stroke affects which tract?

A. Corticospinal
B. Corticobulbar
C. Corticopontine
D. Corticorubral

Answer 26

B. Corticobulbar

THese affect facial nerve and facial nerve nucleus

Corticobulbar tract projects from cerebral cortex to cranial nerve nuclei