Chapter 7 : Tracts of the Spinal Cord (4) Flashcards
- The ability to recognize an unseen familiar 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 unseen familiar object is called stereognosis. This is an important function of the dorsal column–medial lemniscus system.
- The spinal tract involved with the control of trunk muscles is the (A) cuneocerebellar (B) vestibulospinal (C) ventral corticospinal (D) lateral corticospinal (E) ventral spinocerebellar
2–C. The ventral corticospinal tract is concerned with the control of axial muscles, including the muscles of the trunk and head.
- The sensation produced by a wisp of cotton on one’s fingertip is mediated by the (A) cuneocerebellar tract (B) dorsal column–medial lemniscus pathway (C) ventral spinocerebellar tract (D) ventral corticospinal tract (E) ventral spinothalamic tract
3–E. The ventral spinothalamic tract is concerned with light touch, the sensation produced by stroking glabrous skin with a wisp of cotton.
- First-order neurons of the ventral spinocerebellar tract (A) are found in dorsal root ganglia at all levels (B) provide the afferent limb for muscle stretch reflexes (C) project axons into the medial root entry zone (D) give rise to the fasciculus cuneatus (E) project axons via the tract of Lissauer
4–B. First-order neurons of the ventral spino cerebellar tract provide the afferent limb for muscle stretch reflexes. They are found in the dorsal root ganglia from L1 to S2 and synapse on spinal border cell. First-order neurons of the ventral spinothalamic and dorsal spinocerebellar tracts project axons into the medial root entry zone; first-order neurons of the dorsal column–medial lemniscus pathway give rise to the fasciculus gracilis and cuneatus; and first-order neurons of the lateral spinothalamic tract project axons via the dorsolateral tract of Lissauer.
- Acute-stage upper motor neuron lesions result in (A) hypertonia (B) spastic paresis (C) flaccid paralysis (D) extensor toe response (E) clonus
5–C. Acute-stage upper motor neuron lesions result in transient spinal shock, which includes flaccid paralysis, areflexia, and hypotonia. Chronic-stage lesions result in spastic paresis, hypertonia, reduction or loss of superficial abdominal and cremasteric reflexes and extensor toe response, and clonus.
The response options for items 6 to 10 are the same. 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 appropriate spinal cord tract. 6. Contains axons from the giant cells of Deiters
6–G. The vestibulospinal tract arises from the giant cells of Deiters found in the ipsilateral lateral vestibular nucleus of the pons. The vestibulospinal tract facilitates extensor muscle tone.
The response options for items 6 to 10 are the same. 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 appropriate spinal cord 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 to 10 are the same. 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 appropriate spinal cord 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 to 10 are the same. 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 appropriate spinal cord tract. 9. Contains axons from the giant cells of Betz
9–D. The lateral corticospinal tract contains axons from the giant cells of Betz. The giant pyramidal cells of Betz are found in the precentral gyrus and in the anterior paracentral lobule.
The response options for items 6 to 10 are the same. 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 appropriate spinal cord tract. 10. Contains ipsilateral pain fibers that have their second-order neurons in the dorsal horn
10–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 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 pain and temperature sensation.
13–E. The lateral corticospinal tract has its cells of origin in the premotor, motor, and sensory cortices. The precentral gyrus and the anterior paracentral lobule are motor cortices and contain the motor homunculus. The lateral corticospinal gives rise to one-third of the fibers of the corticospinal (pyramidal) tract.
14–F. The fasciculus cuneatus mediates two-point tactile discrimination from the hand.
15–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.
16–E. Transection of the lateral corticospinal tract results in spastic paresis (exaggerated MSRs and clonus).
17–D. The vestibulospinal (lateral) tract, found ventral to the ventral horn, plays a role in regulating extensor tone.
