Test 1

Question 1

Paresis =

Answer 1

Weakness (partial)

Question 2

Plegia =

Answer 2

No voluntary movement

Question 3

Paralysis =

Answer 3

No voluntary movement

Question 4

Palsy =

Answer 4

Weakness or no movement

Question 5

Hemi-

Answer 5

One side of body

Question 6

Para-

Answer 6

Both legs

Question 7

Mono-

Answer 7

One limb

Question 8

Di-

Answer 8

Both sides of body equally affected

Question 9

Quadra- or Tetra-

Answer 9

All four limbs

Question 10

UMN cell bodies are located in the…

Answer 10

Cell bodies in motor cortex or brainstem.

Question 11

LMN cell bodies are located in the…

Answer 11

Spinal cord and brainstem.

Question 12

UMN project to…

Answer 12

Projections descend within the CNS to govern activity of lower motor neuron cell bodies.

Question 13

LMN project to…

Answer 13

Project to muscles in the periphery.

Question 14

Can you have damage to the CNS if you only damage a LMN?

Answer 14

Yes! This is due to the LMN cell bodies residing in the spinal cord and brainstem.

Question 15

What is the most common type of LMN and what is their target?

Answer 15

Alpha motor neuron; skeletal muscle.

Question 16

UMNs are divided into…

Answer 16

Medial and lateral motor systems

Question 17

Difference between Lateral Motor System vs Medial Motor System.

Answer 17

Lateral motor system descends in the lateral column of the spinal cord and synapses on lateral ventral horn motor neurons and interneurons. These are going to control DISTAL limb muscles. Medial motor system descends in the medial column of the spinal cord and synapse on medial ventral horn and interneurons. These control PROXIMAL axial muscles.

Question 18

What does somatotopic mean?

Answer 18

How the cortex is organized by brain regions.

Question 19

True or False: Medial motor systems only synapse ipsilaterally.

Answer 19

False: Medial motor systems can synapse both ipsilaterally and bilaterally.

Question 20

What are the tracts that make up the lateral motor system?

Answer 20

Lateral corticospinal tract and rubrospinal tract.

Question 21

What are the tracts that make up the medial motor system?

Answer 21

Anterior corticospinal tract, vestibulospinal tracts (medial and lateral), reticulospinal tracts, and tectospinal tract.

Question 22

Why are all the descending motor pathways tracts?

Answer 22

They only consist of a single UMN with no synapses.

Question 23

The two lateral motor systems descend in the CONTRALATERAL or IPSILATERAL lateral spinal cord. The two lateral motor systems control the CONTRALATERAL or IPSILATERAL extremities.

Answer 23

Contralateral, contralateral.

Question 24

Descending motor systems are functionally organized into what two types of tracts?

Answer 24

Pyramidal tracts and extrapyramidal tracts.

Question 25

What are pyramidal tracts? What tracts are included?

Answer 25

They originate in the cortex and control VOLUNTARY movement. They terminate on LMN cell bodies in the brainstem and spinal cord. The corticobulbar and corticospinal tracts are included.

Question 26

What are extrapyramidal tracts? What tracts are included?

Answer 26

They originate in the brainstem and control INVOLUNTARY and AUTOMATIC movement. Tracts include the rubrospinal, vestibulospinal, reticulospinal, and tectospinal.

Question 27

How are tracts named?

Answer 27

Based on their origin-destination.

Question 28

Will you see direct UMN signs when you damage pyramidal tracts? Extrapyramidal?

Answer 28

If you damage the pyramidal tract, you will present with UMN signs. If you damage the extrapyramidal tract, you will not see DIRECT UMN signs.

Question 29

Lateral Corticospinal Tract:
Origin-
Decussation-
Level of termination-
Function-

Answer 29

Origin- primary motor cortex
Decussation- decussation of pyramids
Level of termination- lateral ventral horn, entire cord
Function- voluntary movement of contralateral limbs

Question 30

At the decussation of pyramids, what happens to the fibers of the lateral corticospinal tract?

Answer 30

85% of the fibers cross, others continue as anterior corticospinal tract.

Question 31

Somatotopic organization in the cortex for the arms and legs? All other levels?

Answer 31

Cortex: legs medial, arms lateral
All other levels: legs lateral, arms medial

Question 32

What cranial nerves cross at the level of the cranial nerve nuclei? How are these different compared to the rest of the corticobulbar fibers?

Answer 32

CN V - trigeminal, muscles of mastication: upper pons
CN VII - facial, lower facial muscles - lower pons
CN XII - hypoglossal, tongue protrusion: medulla
The rest of the corticobulbar fibers will affect the left and right fibers. If we damage the fibers on the left, we may see nothing because the fibers on the right can compensate and “hide” the symptoms.

Question 33

Rubrospinal tract:
Origin-
Decussation-
Level of termination-
Function-

Answer 33

Origin- red nucleus
Decussation- ventral tegmental decussation (midbrain)
Level of termination- lateral ventral horn and intermediate zone, cervical cord
Function- movement of contralateral upper limb

Question 34

Anterior Corticospinal tract:
Origin-
Decussation-
Level of termination-
Function-

Answer 34

Origin- primary motor cortex
Decussation- some remain ipsilateral, some cross in the ventral white commissure of the spinal cord
Level of termination- cervical and upper thoracic cord
Function- bilateral axial and girdle muscles

Question 35

Medial Vestibulospinal tract:
Origin-
Decussation-
Level of termination-
Function-

Answer 35

Origin- medial and inferior vestibular nuclei
Decussation- descends bilaterally
Level of termination- cervical and upper thoracic cord
Function- positioning of the head and neck

Question 36

Lateral Vestibulospinal tract:
Origin-
Decussation-
Level of termination-
Function-

Answer 36

Origin- lateral vestibular nucleus
Decussation- does not cross
Level of termination- entire cord
Function- balance