Formative

Question 1

Spinal tracts are broadly divided into which two categories?

Answer 1

• Ascending.

- Descending.

Question 2

Descending spinal tracts are divided into which two categories?

Answer 2

• Extrapyramidal.

- Pyramidal.

Question 3

Pyramidal tracts are divided into which two categories?

Answer 3

• Corticospinal.

- Corticobulbar.

Question 4

Origin of the corticospinal tract?

Answer 4

Primary motor cortex in precentral gyrus.

Question 5

Corticospinal tract made up of which two parts?

Answer 5

• Lateral corticospinal.

- Anterior corticospinal.

Question 6

Describe decussation of lateral corticospinal tract.

Answer 6

Pyramidal decussation.

Question 7

Describe decussation of anterior corticospinal tract.

Answer 7

Segmental decussation.

Question 8

Function of lateral corticospinal tract?

Answer 8

• Voluntary motor control of limbs and digits.

Question 9

Function of anterior corticospinal tract?

Answer 9

• Voluntary motor control of trunk and maintenance of posture.

Question 10

Origin of corticobulbar tracts?

Answer 10

Primary motor cortex of precentral gyrus.

Question 11

Function of corticobulbar tracts?

Answer 11

• Control of muscles of face, head and neck (contains UMNs of CNs).

Question 12

Corticobulbar tracts are responsible for bilateral innervation to CN nuclei, with the exception of?

Answer 12

• CN XII (hypoglossal).

- Lower part of CN VII (facial).

Question 13

A peripheral lesion of CN VII will cause what condition with what signs?

Answer 13

Bell’s palsy.

• NO forehead sparing.
• > Forehead and lip droop.

Question 14

A central lesion of CN VII will cause what signs, and may be caused by what condition?

Answer 14

Stroke.

• Forehead sparing.
• > Lip droop.

Question 15

What are the two categories of extrapyramidal tracts?

Answer 15

• Rubrospinal tract.

- Reticulospinal tract.

Question 16

Describe the origin of the rubrospinal tract.

Answer 16

Originates from the red nucleus in the midbrain.

Question 17

Function of the rubrospinal tract.

Answer 17

In the upper body:

• Excites flexor muscles.
• Inhibits extensor muscles.

Question 18

Describe the origin of the reticulospinal tract.

Answer 18

Originates in the pons/medulla.

Question 19

Function of the reticulospinal tract?

Answer 19

• Excite extensors.

Question 20

Describe decorticate rigidity.

Answer 20

• Flexed wrists and fingers.
• Adducted shoulders.
• Flexed elbows.
• Internally rotated thighs.
• Plantar flexion.

Question 21

Describe decerebrate rigidity.

Answer 21

• Adducted shoulders.
• Extended elbows.
• Pronated forearms.
• Flexed wrists and fingers.
• Plantar flexion.

Question 22

Ascending spinal tracts are divided into which two tracts?

Answer 22

• DCML pathway.

- Spinothalamic tract.