Chapter 7 : Tracts of the Spinal Cord (3) Flashcards
- The ability to recognize an unseen familiar Questions 6-10 object placed in the hand depends on the integrity of which pathway? (A) Spinospinal tract (B) Dorsal column (C) Dorsal spinocerebellar tract (D) Spino-olivary tract . (E) Spinothalamic tract
1-B. The ability to recognize the form and texture of an ungeen familiar object is called stereognosis. This is an important function of the dorsal column-medial lemniscus system.
- All of the following statements concerning the corticospinal tracts are correct EXCEPT (A) they arise from lamina V of the cerebral cortex (B) they arise from upper motor neurons (UMNs) (C) they descend through the anterior limb of the internal capsule (D) they undergo a 90% decussation in the caudal medulla (E) they descend through the base of the pons
2-C. The corticospinal tracts arise from upper motor neurons (UMNs) found in lamina V of the cerebral cortex.They descend through the posterior limb ofth(‘ internal capsule. the middl8 third of the crus cerebri (basis pedunculi) of the midbrain, and the base of the pons and consti tute the medullary pyramids. Ninety percent of the corticospinal fibers decussate in the caudal medulla as the pyramidal decussation.
- Destruction of the ventral horn results in all of the following deficits EXCEPT (A) loss of muscle stretch reflexes (MSRs) (B) loss of muscle bulk (C) flaccid paralysis (D) Babinski sign (E) loss of superficial abdominal reflexes
3-D. Destruction of ventral horn motor neurons results in a lower motor neuron (LMN) lesion and is characterized by flaccid paralysis, muscle atrophy (loss of muscle bulk), and areflexia (loss of muscle stretch and superficial abdominal reflexes). The Babinski sign is not seen in LMN disease.
- All of the following tracts decussate in the ventral white commissure EXCEPT the (A) lateral spinothalamic tract (B) ventral spinocerebellar tract (C) ventral corticospinal tract (D) dorsal spinocerebellar tract (E) ventral spinothalamic tract
4-D. The dorsal spinocerebellar tract is an uncrossed tract.
- The corticospinal tracts receive contribu¬tions from all of the following areas EXCEPT the (A) prcfrontnl cortex (B) premotor cortex (C) motor cortex (D) somatesthetic cortex (E) paracentral lobule
5-A. The corticospinal (pyramidal) tracts receive contributions from the premotor (area 6), motor (area 4), and the sensory or somatesthetic (areas 3, 1, and 2) cortices. They receive approximately one-third of their axons from each of these cortical arcus. The puracentrallobule represents a continuation of the motor and somatesthetic cortics onto the medial aspect of the hemisphere. The prefrontal cortex lies rostral to the premotor cortex.
The response options for items 6-10 are the same. You will be required to select one answer for each item in the set. (A) Cuneocerebellar tract (B) Cuneate fasciculus (C) Dorsal spinocerebellar tract (D) Lateral corticospinal tract (E) Lateral spinothalamic tract (F) Lissauer tract (G) Vestibulospinal tract Match each statement below with the appro¬priate spinal cord tract_ 6. Contains axons from the giantcells of Deiters
6-G. The vestibulospinal tract arises from the giant cells of Deiters found in the ipsilaterallateral vestibular nucleus of the pons. The vestibulospinal tract facilitates extensor muscle tone.
The response options for items 6-10 are the same. You will be required to select one answer for each item in the set. (A) Cuneocerebellar tract (B) Cuneate fasciculus (C) Dorsal spinocerebellar tract (D) Lateral corticospinal tract (E) Lateral spinothalamic tract (F) Lissauer tract (G) Vestibulospinal tract 7. Is the upper extremity equivalent of a tract that arises from the cells of Clarke column
7-A. The cuneocerebellar tract is the upper extremity equivalent of the dorsal spinocerebellar tract, which arises from the cells of the Clarke column. The cuneocerebellar tract arises from cells of the accessory cuneate nucleus. a homolog of the nucleus of Clarke.
The response options for items 6-10 are the same. You will be required to select one answer for each item in the set. (A) Cuneocerebellar tract (B) Cuneate fasciculus (C) Dorsal spinocerebellar tract (D) Lateral corticospinal tract (E) Lateral spinothalamic tract (F) Lissauer tract (G) Vestibulospinal tract 8. Conveys nociceptive input from the contralateral side of the body
8-E. The lateral spinothalamic tract conveys nociceptive input from the contralateral side of the body.
The response options for items 6-10 are the same. You will be required to select one answer for each item in the set. (A) Cuneocerebellar tract (B) Cuneate fasciculus (C) Dorsal spinocerebellar tract (D) Lateral corticospinal tract (E) Lateral spinothalamic tract (F) Lissauer tract (G) Vestibulospinal tract 9. Contains axons from the giant cells of Betz.
9-D. The lateral corticospinal tract contuins uxons from the giant cells of Betz. ‘rhe I,
The response options for items 6-10 are the same. You will be required to select one answer for each item in the set. (A) Cuneocerebellar tract (B) Cuneate fasciculus (C) Dorsal spinocerebellar tract (D) Lateral corticospinal tract (E) Lateral spinothalamic tract (F) Lissauer tract (G) Vestibulospinal tract 10. Contains ipsilateral pain fibers that have their second-order neurons in the dorsal horn
IO-F. The dorsolateral tract of Lissauer contains ipsilateral pain fibers that have their secondorder neurons in the dorsal horn.
11-B. The dorsal spinocerebellar tract projects unconscious proprioceptive information [muscle spindles and Golgi tendon organs (GTOs)) to the cerebellum via the inferior cerebellar peduncle.
12-C.· The lateral spinothalamic tract lies between the ventral spinocerebellar tract and the ventral horn. It mediates pail. and temperature sensation
I3-E. The lateral corticospinal tract has its cells of origin in the premotor, motor, and sensory cortices. The precentral gyrus l\I1d the anterior pllracentrallobule are motor cortices and contain the motor homunculus. It gives rise to one· third of the fibers of the corticospinal (pyramidal) tract.
I4-F. The fasciculus cuneatus mediates two-point tactile discrimination from the hand.
I5-E. The corticospinal (pyramidal) tracts are not fully myelinated until the end of the second year. For this reason, the Babinski sign may be elicited in young children.
I6-E. Transection ofthe lateral corticospinal tract results in spastic paresis [exaggerated muscle stretch reflexes (MSRs) and clonus].
I7-D. The vestibulospinal (lateral) tract, found ventral to the ventral horn, plays a role in regulating extensor tone.
