Chapter 6 : Spinal Cord (2)

Question 1

1. All of the following statements concerning the substantia gelatinosa are correct EXCEPT
   (A) it is found at all spinal cord levels
   (B) it is a sensory nucleus
   (C) it plays a role in mediating pain and temperature
   (D) it is homologous to the spinal trigeminal nucleus
   (E) it is greatly reduced in size at sacral levels

Answer 1

l-E. The substantia gelatinosa is greatly enlarged at sacral levels. It is a sensory nucleus found at all cord levels. It mediates pain and temperature and is homologous to the spinal trigeminal nucleus.

Question 2

2. Which statement concerning the dorsal root ganglion is FALSE?
   (A) It contains pseudounipolar neurons
   (B) It is located within the intervertebral foramen
   (C) It contains neurons of neural crest origin
   (D) It usually is missing at CI
   (E) It lies within the subarachnoid space

Answer 2

2-E. The dorsal root ganglion contains large (proprioception) and small (pain and temperature)
pseudounipolar neurons of neural crest origin and lies within the intervertebral foramen. It usually is absent in the first cervical nerve and in the coccygeal nerve.

Question 3

3. Which statement concerning the lateral horn is FALSE?
   (A) It receives viscerosensory input
   (B) It is found at the level of the phrenic nucleus
   (C) It is coextensive with the nucleus dorsalis of Clarke
   (D) It contains a visceromotor nucleus
   (E) It corresponds to Rexed lamina VII

Answer 3

3-B. The lateral horn extends from (C8) Tl to L3. The phrenic nucleus extends from C3 to C6.
The nucleus dorsalis of Clarke is coextensive with the lateral horn and its intermediolateral nucleus or cell column. Rexed lamina VII (lamina intermedia) includes the sympathetic intermediolateral nucleus, the parasympathetic sacral nucleus (S2-S4), and the nucleus dorsalis of Clarke.

Question 4

4. All of the following statements concerning the spinal cord are correct EXCEPT
   (A) it represents 2% of brain weight
   (B) it terminates in the adult at VL1-VL2
   (C) it lies within the subarachnoid space
   (D) it terminates in the newborn at VS2
   (E) it contains 31 pairs of spinal nerves

Answer 4

4-D. In the newborn, the spinal cord ends at the level of the third lumbar vertebra (VL3). In the adult, the spinal cord ends at the level of the interspace between the first and second lumbar vertebrae (VL1-VL2). In the adult, the dural cul-de-sac ends at the level of the second sacral vertebra (VS2).

Question 5

5. All of the following statements concerning spinal nerves are correct EXCEPT
   (A) dorsal roots contain sensory input
   (B) ventral roots contain motor output
   (C) all spinal nerves have gray communicating rami
   (D) all spinal nerves have white communicating rami
   (E) the first cervical nerves frequently have no dorsal roots

Answer 5

5-D. White communicating rami are found only at thoracolumbar levels of the spinal cord (T1-L3); they contain myelinated preganglionic sympathetic fibers and myelinated GVA fibers (from splanchnic nerves). Gray communicating rami contain unmyelinated postganglionic sympathetic fibers and contribute to all spinal nerves. The first cervical nerve and the coccygeal nerve usually have no dorsal (sensory) roots.

Question 6

6. All of the following statements concerning the cauda equina are correct EXCEPT
   (A) it contains motor fibers
   (B) it contains sensory fibers
   (C) it is found in the subarachnoid space
   (D) it is derived from the pia
   (E) it is found below the first lumbar vertebra

Answer 6

6-D. The cauda equina consists of lumbosacral nerve roots that descend below the level of the
conus medullaris, within the subarachnoid space, to exit through their respective intervertebral
or sacral foramina. Dorsad roots contain sensory fibers; ventral roots contain motor fibers.The cauda equina syndrome affects the lumbosacral nerve roots, producing both sensory and motor symptoms.

Question 7

7. All of the following statements concerning the myotatic reflex are correct EXCEPT
   (A) it is a monosynaptic and ipsilateral reflex
   (B) it is a muscle stretch reflex
   (C) it includes a muscle spindle
   (D) it includes a ventral horn motor neuron
   (E) the cell body of afferent nerve fiber is found in the dorsal horn

Answer 7

7-E. The myotatic reflex is a monosynaptic and ipsilateral muscle stretch reflex (MSR;incorrectly
called a deep tendon reflex). The afferent limb consists of a muscle spindle (receptor) and a la fiber (axon) of a dorsal root ganglion neuron; the efferent limb consists of the axon of a ventral horn alpha motor neuron and the innervated striated muscle fibers (effector). The quadriceps (patellar) and triceps surae (ankle) muscle stretch reflexes are examples of myotatic reflexes.

Question 8

Match each of the statements below to the structure most closely associated with it.
(A) Dorsal intermediate septum
(B) Ventral lateral sulcus
(C) Dorsal median sulcus
(D) Dorsal lateral sulcus
(E) Ventral median fissure

8. Contains the sulcal branch of an artery

Answer 8

8-E. The ventral median fissure contains the sulcal branch of the ventral (anterior) spinal artery.

Question 9

Match each of the statements below to the structure most closely associated with it.
(A) Dorsal intermediate septum
(B) Ventral lateral sulcus
(C) Dorsal median sulcus
(D) Dorsal lateral sulcus
(E) Ventral median fissure

9. Receives dorsal roots

Answer 9

9-D. The dorsal lateral sulcus receives the dorsal roots.

Question 10

Match each of the statements below to the structure most closely associated with it.
(A) Dorsal intermediate septum
(B) Ventral lateral sulcus
(C) Dorsal median sulcus
(D) Dorsal lateral sulcus
(E) Ventral median fissure

10. Is not found at lumbar levels

Answer 10

10-A. The dorsal intermediate septum extends from CI to T6. It is diagnostic for cervical and
upper thoracic cord segments.

Question 11

Match each of the statements below to the structure most closely associated with it.
(A) Dorsal intermediate septum
(B) Ventral lateral sulcus
(C) Dorsal median sulcus
(D) Dorsal lateral sulcus
(E) Ventral median fissure

11. Is located between the fasciculus gracilis and the fasciculus cuneatus

Answer 11

11-A. The dorsal intermediate septum separates the fasciculus gracilis from the fasciculus cuneatus. It is indicative of the cervical and upper thoracic cord.

Question 12

Match each of the statements below to the structure most closely associated with it.
(A) Dorsal intermediate septum
(B) Ventral lateral sulcus
(C) Dorsal median sulcus
(D) Dorsal lateral sulcus
(E) Ventral median fissure

12. Is the zone of emergence for ventral roots

Answer 12

12-B. The ventral lateral sulcus is the zone of emergence for the ventral roots.

Question 13

Match each characteristic below with the spinal cord level it best describes.
(A) Cervical cord
(B) Upper thoracic cord
(C) Lumbar cord
(D) Lower thoracic cord
(E) Coccygeal cord
(F) Sacral cord

13. Contains preganglionic parasympathetic neurons

Answer 13

13-F. The sacral cord contains the sacral parasympathetic nucleus (S2-S4); this gives rise to
preganglionic fibers that synapse in the intramural ganglia of the pelvic viscera

Question 14

Match each characteristic below with the spinal cord level it best describes.
(A) Cervical cord
(B) Upper thoracic cord
(C) Lumbar cord
(D) Lower thoracic cord
(E) Coccygeal cord
(F) Sacral cord

14. Contains massive ventral horns and dorsal intermediate sulcus

Answer 14

14-A. The cervical cord contains massive ventral horns, which give rise to the brachial plexus (C5-C8). The dorsal intermediate sulcus and septum are also indicative of cervical cord levels.

Question 15

Match each characteristic below with the spinal cord level it best describes.
(A) Cervical cord
(B) Upper thoracic cord
(C) Lumbar cord
(D) Lower thoracic cord
(E) Coccygeal cord
(F) Sacral cord

15. Has a ciliospinal center of Budge

Answer 15

15-B. The ciliospinal center of Budge is found in the lateral horn at Tl. This sympathetic nucleus innervates the radial muscle of the iris (dilatator pupillae) and the nonstriated superior and inferior tarsal (Miiller) muscles

Question 16

Match the spinal cord segments (levels) below with the appropriate spinal cord nuclei.
(A) Ciliospinal nucleus of Budge
(B) Cooper-Sherrington border cells
(C) Intermediolateral nucleus
(D) Parasympathetic nucleus
(E) Phrenic nucleus
(F) Spinal accessory nucleus
(G) Substantia gelatinosa

16. Found at all spinal cord levels

Answer 16

16-G. The substantia gelatinosa is found at all spinal cord levels; it plays a role in pain transmission.

Question 17

Match the spinal cord segments (levels) below with the appropriate spinal cord nuclei.
(A) Ciliospinal nucleus of Budge
(B) Cooper-Sherrington border cells
(C) Intermediolateral nucleus
(D) Parasympathetic nucleus
(E) Phrenic nucleus
(F) Spinal accessory nucleus
(G) Substantia gelatinosa

17. Found only in the sacral segments of the spinal cord

Answer 17

17-D. The parasympathetic nucleus of the spinal cord is found in sacral segments S2 to S4.

Question 18

Match the spinal cord segments (levels) below with the appropriate spinal cord nuclei.
(A) Ciliospinal nucleus of Budge
(B) Cooper-Sherrington border cells
(C) Intermediolateral nucleus
(D) Parasympathetic nucleus
(E) Phrenic nucleus
(F) Spinal accessory nucleus
(G) Substantia gelatinosa

18. Extends from CI to C6

Answer 18

18-F. The spinal accessory nucleus extends from CI to C6.

Question 19

Match the spinal cord segments (levels) below with the appropriate spinal cord nuclei.
(A) Ciliospinal nucleus of Budge
(B) Cooper-Sherrington border cells
(C) Intermediolateral nucleus
(D) Parasympathetic nucleus
(E) Phrenic nucleus
(F) Spinal accessory nucleus
(G) Substantia gelatinosa

19. Found only in upper thoracic segments

Answer 19

19-A. The ciliospinal nucleus (center) of Budge provides the sympathetic innervation of the eye and is found at Tl and T2.

Question 20

Match the spinal cord segments (levels) below with the appropriate spinal cord nuclei.
(A) Ciliospinal nucleus of Budge
(B) Cooper-Sherrington border cells
(C) Intermediolateral nucleus
(D) Parasympathetic nucleus
(E) Phrenic nucleus
(F) Spinal accessory nucleus
(G) Substantia gelatinosa

20. Found within the entire extent of the lateral horn

Answer 20

20-C. The intermediolateral nucleus is found within the entire extent of the lateral horn (C8-L3). It contains all of the preganglionic sympathetic neurons of the sympathetic nervous system.