Lec 13: Review of Anatomy, Physiology and Motor Exam

Question 1

Where are most of the upper motor neurons located?

Answer 1

precentral gyrus (Brodmann area 4)

Question 2

What are the tracts connected to the cortical motor neurons?

Answer 2

corticospinal, corticobulbar, corticorubrospinal, corticoreticulospinal, corticovestibulospinal, corticotectospinal

Question 3

Where are lower motor neurons located in the corticospinal tract?

Answer 3

anterior horn of the spinal cord (composed of alpha motor neurons and projections to muscles)

Question 4

Where are lower motor neurons located in the corticobulbar tract?

Answer 4

cranial nerve motor nuclei of motor and mixed CNs along with projections to the muscles of the face, head, and neck

Question 5

Why is denervation atrophy more pronounced in LMN paralysis?

Answer 5

in an UMN paralysis, there is still stimulation from the LMN

Question 6

What causes spasticity and hyperreflexia in UMN paralysis?

Answer 6

lack of inhibition from the UMNs causes the LMN to function primitively and without inhibition

Question 7

(T/F) An abnormal EMG-NCV is reflective of both UMN and LMN dysfunction.

Answer 7

F

Question 8

What are the direct activation pathways?

Answer 8

corticospinal and corticobulbar tracts

Question 9

What is the function of direct activation pathways?

Answer 9

make muscles move and give strength (gross movement

)

Question 10

What are the control circuits?

Answer 10

basal ganglia, cerebellum, and thalamus

Question 11

What are the indirect activation pathways?

Answer 11

rubrospinal, vestibulospinal, reticulospinal, and tectospinal

Question 12

What is the only part of the body with Betz (giant pyramidal cells) cells?

Answer 12

corticospinal tract

Question 13

What are the components of the final common pathway?

Answer 13

LMN with muscle that it innervates

Question 14

What are the different types of movement?

Answer 14

reflex, voluntary movement, rhythmic motor patterns

Question 15

What is the main neurotransmitter of DAPs?

Answer 15

glutamate

Question 16

How can you differentiate a supratentorial from an infratentorial lesion based on primary gaze?

Answer 16

supratentorial - towards lesion

infratentorial - away from lesion

Question 17

Where does decussation occur for the fibers of the corticospinal tract?

Answer 17

medullary pyramids

Question 18

What is the order of the innervating fibers of the corticospinal tract when passing through the posterior limb of the internal capsule?

Answer 18

leg -> arm -> trunk -> head (lateral to medial)

Question 19

What is the order of the innervating fibers of the corticospinal tract when passing through the lateral funiculus?

Answer 19

sacral -> lumbar -> thoracic -> cervical (lateral to medial)

Question 20

Which CNs do not have corticobulbar tracts fibers?

Answer 20

CN I, II, VIII (purely sensory)

Question 21

Which is more medial? corticospinal or corticobulbar tract fibers?

Answer 21

corticobulbar

Question 22

How can you differentiate a central facial palsy from a peripheral facial palsy?

Answer 22

CFP - contralateral paralysis of the LOWER half of the face

PFP - ipsilateral hemiparalysis

Question 23

What is the neurotransmitter used in the final common pathway?

Answer 23

acetylcholine

Question 24

What are the two types of sensory receptors in muscles?

Answer 24

muscle spindle - conveys stretch sensation

golgi tendon organ - senses muscle tension

Question 25

What types of afferent fibers regulate the golgi tendon and stretch reflexes?

Answer 25

stretch - IA

GT - IB