Supraspinal Motor Systems: Pyramidal System Flashcards
Corticalbulbar tract
Starts at _____
PRojects to ______
Motor cortex to cranial nerve nuclei
Corticalspinal tract
Starts at _____
PRojects to ______
Motor cortex to spinal cord
Most corticospinal/pyramidal tract originate from:
Primary motor cortex
Lower limbs are in which area of motor and sensory homunculi?
A. Medial
B. Dorsal
C. Lateral
D. Rostral
A. Medial
The face is in which area of motor and sensory homunculi?
A. Medial
B. Dorsal
C. Lateral
D. Rostral
C. Lateral
Which corticospinal tract decussates and continues on contralateral side of body?
Lateral corticospinal tract
Which corticospinal tract does not decussate and continues on ipsalateral side of body
Ventral/anterior corticospinal tract
Where does lateral corticospinal tract decussate?
Caudal medulla
Lateral corticospinal tract fibers that end in higher segment are typographically located:
A. Most lateral
B. Most ventral
C. Most medial
D. Most caudal
C. Most medial
Lateral corticospinal tract fibers that end in lower segment are typographically located:
A. Most lateral
B. Most ventral
C. Most medial
D. Most caudal
A. Most lateral
True or false: The vast majority of corticospinal fibers do NOT decussate
False, the vast majority DO decussate (80-90%)
The majority (55%) of pyramidal/corticospinal fibers end in the ________ spinal cord?
A. Thoracic
B. Lumbar
C. Sacral
D. Cervical
D. Cervical spinal cord
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
B. Hands
In the pyramidal system
Upper motors neurons consist of __________
Lower motor neurons consist of _______
Upper motors neurons consist of Corticospinal tract (pyramidal cells)
Lower motor neurons consist of alpha motor neurons (ventral horn cells)
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
A. Upper motor corticospinal lesion
Abnormal activation of intact brain stem and spinal pathways
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
C. Lower motor neuron corticospinal
Loss of alpha motor innervation to muscle
What is a positive Babinski sign?
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
Spasticity explanation
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
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
C. Above red nucleus
A lesion here would cause hyperactivity of red nucleus which would cause abnormal flexion of upper extremities
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
B. Below red nucleus
Lesion here would cause hyperactivity of vestibular nuclei which causes excessive extension
In the corticobulbar tract,
Upper motor neurons are in __________
Lower motor neurons are in ________
Upper motor neurons are in the cerebral cortex
Lower motor neurons are in cranial nuclei
Patient suffered from a stroke what would you typically see in this patient? What type of lesion is it?
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
Patient was diagnosed with Bell’s palsy, what would you typically see in this patient? What type of lesion is it?
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
Why does stroke only have paralysis of lower contralateral face?
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
Why does bell-s palsy affect ipsalateral upper and lower face?
Lower motor neuron (facial n) lesion affects motor neurons after decussation. Facial nerve innerv upper and lower ipsalateral face
Bell’s palsy and stroke affects which tract?
A. Corticospinal
B. Corticobulbar
C. Corticopontine
D. Corticorubral
B. Corticobulbar
THese affect facial nerve and facial nerve nucleus
Corticobulbar tract projects from cerebral cortex to cranial nerve nuclei
