MOTOR SYSTEM UMN

Question 1

upper motor neuron may arise from the

Answer 1

brainstem or cerebral cortex

Question 2

lower motor neuron is found in the

Answer 2

Brain stem & spinal cord

Question 3

Tracts from the cortex

Answer 3

● Corticospinal tract
● Corticobulbar tract

Question 4

Tracts from the brain stem (anteriomedial pathway)

Answer 4

● Vestibulospinal tract (Lat and Med)
● Reticulospinal tract (pontine & medullary)
● Rubroospinal tract
● Tectospinal tract

control axial muscles, posture and balance

Question 5

Corticospinal fibers are essential for
corticobulbar fibers innervate

Answer 5

fine and voluntary movements, mainly of the distal extremities (lateral corticospinal fibers) & proximal extremities (anterior corticospinal fibers)
cranial nerves motor nuclei and head and neck region

upper motor neurons thus serve as
the anatomical substrate for voluntary
control of the muscles of facial expression,
eye movements, jaw opening and closing,
and movements of the tongue.

Question 6

corticospinal tract pathway starts from

Answer 6

Internal pyramidal layer (Layer 5 of cerebral cortex ) of M1(primary mortor cortex ), PMC (premotor cortex), SMA (supplementary motor area), S1(primary somatosensory receiving area)

Question 7

Primary moter cortex, M1 (Occupies precentral gyrus, may be marked as M1 or B4
(Brodmann 4)

Medial portion
Lateral portion

Answer 7

The medial and superior portions control the muscles of the feet and legs
The lateral portions control the muscles of the thorax, arms and head.

Each primary motor cortex controls the muscles on the opposite side of t

Question 8

Anteriorly to the PMC is the Brodmann area 6

Answer 8

Supplementary motor area, SMA (medially)
Premotor cortex, PMC (laterally)

Question 9

Cortex which anticipates and plans movements based on external sensory
cues, such as responses to events that are seen or heard.

Answer 9

premotor cortex

Question 10

Area that selects and plans complex movements involving both sides of the body based on internal cues, such as thoughts or memory.

Answer 10

supplementary motor area

Question 11

posterior parietal cortex (or Brodmann
areas 5 and 7) function

Answer 11

It receives and integrates visual, auditory,
and somatosensory (sense of body) inputs
from other brain areas.

From these inputs, it produces information
about the position of the bod

Question 12

posterior parietal cortex lesion causes

Answer 12

apraxia

Question 13

lesions of the SMA (or/and PMC) display

Answer 13

Apraxia - the inability to initiate specific, purposeful movements, even though the sensory and motor pathways for the execution of the movement remain intact.

Question 14

inability to execute a movement upon request.

Answer 14

Ideomotor apraxia

patient to be able to brush his or her hair or tie

Question 15

inability to conceptualize the movements, and the patient is unable to identify the
sequences of movements that are necessary for carrying out the response in question.

Answer 15

Ideational apraxia

Commonly, the apraxia becomes evident when the patient is asked to perform, simultaneously, different
movements of both arms.

Question 16

lesions of the PMC,

Answer 16

patient is unable to coordinate the movement of both arms at the same time.

loss of strength in the proximal muscles of the contralateral arm or leg & difficulty in raising or abducting that limb.

Question 17

posterioir parietal cortex PPC

Answer 17

coordiantes movements or in preparation for a goal-directed response such as reaching out to grab an object.

Question 18

lesions of the right PPC show two types of disorders:

Answer 18

1. Apraxia (smilar to SMA and PMC apraxia)
2. Sensory neglect (or anosognosia)

Question 19

Corticobulbar tract run lateral to the PMC

Answer 19

Descends through the genu of the internal
capsule

Question 20

Most corticobulbar fibers

directed toward cranial nerve motor nuclei innervate these neurons bilaterally. Exception:

Answer 20

CN 7 & CN 12

Contralateral innervation of ventral cell
groups of the motor nucleus of cranial
nerve (CN) VII (supplies muscles of the
lower quadrants of the face (below the
eyes).

Question 21

Stroke vs bell’s palsy

Answer 21

Stroke - unilateral UMN with lower face paralysis (forehead sparing)

Bell’s palsy - unilateral LMN lesion of the CN7 nucleus with no forehead sparing

Question 22

Rubrospinal tract

Receptors is - Red nucleus in rostral half of midbrain tegmentum

Answer 22

facilitate flexor motor neurons and inhibit extensor motor neurons

Question 23

lesion on the rubrospinal tract

Answer 23

C/L motor disturbances (trmors, choreiform activity, ataxia, )

due to involvement of axons arising from basal ganglia

Question 24

Tectospinal tract

receptor is in superioir colliculus

Answer 24

Direct head and neck movement in response to visual and auditory stimulus

Question 25

Lateral vestibulospinal tract

Receptor: Lateral vestibulospinal nucleus (border of the pons and medulla)

Answer 25

I/L extensor alpha motor neurons (extensor muscles of the trunk) and associated gamma motor neurons (I/L limb)

Question 26

Lesion of vestibulospinal tract

Answer 26

disturbances in maintaining balance and posture

Question 27

Medial vestibulospinal tract

Receptor : I/L and C/L Medial vestibular nuclei

Answer 27

adjust head position in response to changes in posture (e.g keeping head stable when walking)

Question 28

lesion of medial vestibulospinal tract

Answer 28

Disturbances in head positioning when body position is afected

Question 29

Reticulospinal tract

Answer 29

Receptors in medulla- inhibits extensor spinal reflex
Recptors in pons-facilitates extensor spinal reflex

Question 30

Lesion of reticulospinal tract

Answer 30

in medulla- contribute to spacicity in UMN paralysis
in pons -loss of extensor muscle tone

Question 31

vascular supply of the primary motor cortex

Answer 31

middle cerebral artery and anterioir cerebral artery

Question 32

Middle cerebral artery supplies

Answer 32

Lateral convexity of the hemisphere:
broca’s and wernicke’s speech area
face and arm area of the motor & sensory cortices
Frontal eye field
post. limb of internal capsule

Question 33

The lateral striate arteries (branches of the MCA) supply

Answer 33

internal capsule, caudate nucleus, putamen and globus pallidus

Question 34

Arteries of stroke are the

Answer 34

Lateral striate arteries (Penetrating branches of MCA)

Question 35

Homonymous hemianopia (loss of half of the visual field in both eyes) is due to damage

Answer 35

to visual cortex

Question 36

infarcts of the lenticulostriate arteries of internal capsule (supplying superior internal capsule) cause

Answer 36

PURE MOTOR STROKE - C/L hemiparesis (coricospinal fibers) and lower face droop (corticobulbar fibers)

Question 37

inferior portion of the internal capsule is supplied by

Answer 37

Anterior choroidal artery