M2-C2-L26 --> Upper Motor Neurons I

Front 1

In terms of paralysis, describe the difference btw the LMN and UMN lesions.

Back 1

LMN is flaccid paralysis

UMN is spastic paralysis

Front 2

Which motor neurons does ALS attack?

Back 2

both

Front 3

UMN have projection neurons going from where?

Back 3

Layer V of cerebral cortex

Front 4

What are the pathways of the UMN?

Back 4

Pyramidal

and

Extrapyramidal

Front 5

What type of movement is UMN responsible for?

Back 5

Voluntary

Front 6

Where are most UMN located?

Back 6

Motor/Premotor cortex

Front 7

How does UMN control LMN?

Back 7

Via interneurons in the intermediate zone

Front 8

What type of Pyramidal UMNs (in the Motor cortex) bypass the intermediate zone, allowing for direct connections with LMN?

What does this mechanism control?

Back 8

Betz cells

Hand movement

Front 9

What are the components of the pyramidal tracts?

Back 9

Corticobulbar tract

Corticospinal tract

Front 10

In the midbrain, the majority of pyramidal tract crosses over where?

Back 10

Caudal Medulla

Front 11

In the corticospinal tract, what is the major pathway for voluntary muscle?

Back 11

Lateral Corticospinal tract.

Front 12

What does the lateral corticospinal tract have exclusive control over? and how?

Back 12

Intrinsic muscles of hand.

Via UNN-LMN connection (no interneurons)

Front 13

Is the lateral corticospinal tract a crossed pathway?

Back 13

Yes

Front 14

Is the anterior corticospinal tract a crossed pathway?

Back 14

Yes, but it is also uncrossed too.

Front 15

What does the anterior corticospinal tract control?

Back 15

Proximal musculature on the ipsilateral and contralteral side, chiefly in the upper body

Front 16

Where in the spine does the corticobulbar cross over?

Back 16

Never goes into spine.

Just pons and medulla.

Front 17

Is the corticobulbar tract crossed?

Back 17

Majority is crossed, but some uncrossed also.

Front 18

What areas does the corticobulbar tract control?

Back 18

Face and Oral Cavity

Front 19

Where do corticobulbar neurons cross usually?

Back 19

At the level of the cranial nerve nucleus being innervated.

Front 20

Which portions controls the lower part of the face?

Back 20

Only the CROSSED over portions of the corticobulbar

Front 21

The majority of corticobulbar axons control LMN in which cranial nerves?

Back 21

Facial (CN VII - facial expression)

Vagus (CN X)

Hypoglossal (CN XII - speech)

Front 22

What are the components of the extrapyramidal pathways?

Back 22

Rubrospinal tract

Reticulospinal tract (medial/lateral)

Front 23

Is the rubrospinal a crossed pathway?

Back 23

Yes

Front 24

What does the rubrospinal tract control?

Back 24

Strong EXCITATORY effect on PROXIMAL flexors of the upper extremity.

Front 25

Is the medial reticulospinal tract crossed?

Back 25

Yes, but also uncrossed too.

Front 26

What is the Major Alternate Pathway, and what does it control?

Back 26

Medial reticulospinal tract.

Controls axial and proximal musculature.

Front 27

What pathway has a strong excitatory effect on anti-gravity musculature (axial and extensor musculature)?

Back 27

Medial reticulospinal tract.

Front 28

Is the lateral reticulospinal tract crossed?

Back 28

Yes, but also uncrossed too.

Front 29

What does the lateral reticulospinal tract control?

Back 29

Variety of excitatory and inhibitory movements on axial and proximal limb muscles.

Front 30

Where does the lateral reticulospinal tract cross over?

Back 30

Spinal cord

Front 31

Unilateral lesions may result in incomplete paralysis. Why?

Back 31

Due to pathways being crossed and uncrossed.

Also, due to the Major Alternative Pathway

Front 32

Describe the motor cortex's evocation of muscle.

Back 32

Evokes movement of individual muscles

based on homonculus

Front 33

Describe the threshold for the M1 (Motor Cortex)

Back 33

Low

Front 34

Describe the threshold for the M2 (Premotor Cortex)

Back 34

High

Front 35

Describe the Premotor cortex's evocation of muscle.

Back 35

Evokes mass muscle movements

involving postural adjustments

ipsilaterally and contralaterally

Front 36

What is the supplementary motor cortex?

Back 36

The medial surface of M2

Front 37

Most axons of the pyramidal tract originate where?

Back 37

Motor Cortex

Front 38

Most axons of the extrapyramidal tract originate where?

Back 38

Premotor cortex

Front 39

Lesions in the M2 usually leads to what?

Back 39

Contralateral spasticity of antigravity muscles

due to loss of inhibition by UMN

Front 40

The supplementary motor area evokes what type of movement?

Back 40

Bilateral and sequencing of motor activity

Front 41

What are the possible lesion sites for the UMN?

Back 41

Cerebrum
Internal capsule
Brainstem
Spinal cord

Front 42

UMN lesions usually result in what type of symptoms?

Back 42

1. Spastic paralysis (hemiplegic/hemiparesis)

2. Muscle weakness with Pronator drift (on paretic side)

3. Abnormal reflexes

4. Loss of speed and agility (on paretic side)

5. Loss (complete) of control over distal muscle (intrinsic hand muscles)

Front 43

List the abnormal reflexes associated with UMN lesions.

Back 43

1. Clonus
2. Hoffman's sign
3. Increased DTR
4. Clasp-Knife reflex
5. Babinski sign
6. Superficial reflexes lost.

Front 44

Describe the effects of UMN lesions to the Lower Extremity.

Back 44

Extensor Hypertonia

Gait: stiff, spastic, with circumduction at hip joint.

Front 45

Describe the effects of UMN lesions to the Upper Extremity.

Back 45

Flexor hypertonia

with paralysis of intrinsic hand muscles,

but grasping movement may be spared.

Front 46

A DTR of 0 would indicate a lesion where?

Back 46

LMN

Front 47

A DTR of +1 would indicate a lesion where?

Back 47

LMN and Cerebellar

Front 48

A DTR of +2 would indicate a lesion where?

Back 48

none. it is normal

Front 49

A DTR of +3 would indicate a lesion where?

Back 49

UMN

Front 50

A DTR of +4 would indicate a lesion where?

Back 50

UMN

Front 51

Describe a DTR of +4

Back 51

Hyper reflex with clonus

Front 52

A babinski sign would indicate a lesion in which tract?

Back 52

Pyramidal - Lateral Corticospinal tract.