Cross-Sectional Anatomy of the Spinal Cord

Question 1

The Ventral (anterior) median fissure separates what?

Answer 1

It separates the ventral funiculi (white matter tract regions)

Question 2

The Dorsal (posterior) median sulcus divides what?

Answer 2

It divides dorsal funiculi (white matter tract regions)

Question 3

What does gray matter consist of?

Answer 3

Soma, unmyelinated processes and neuroglia

Question 4

What does Gray commissure connect?

Answer 4

The Gray commissure connects R/L massesof gray matter

& encloses central canal

Question 5

Dorsal horns within Gray Matter columns consist of:

Answer 5

Interneurons

(therefore a sensory synapse will occure here)

Question 6

Ventral horns within Gray Matter Columns consist of:

Answer 6

Somatic (voluntary) motor neurons & some interneurons

Question 7

Lateral horns within Gray Matter Columns contain:

Answer 7

Sympathetic motor fibers

& this column is present in T_1-L₂ only

Question 8

Spinal Roots consist of:

Answer 8

Dorsal half

&

Ventral Half

Question 9

Describe the Dorsal half of the Spinal Root

Answer 9

dorsal root ganglion (sensory nerve cell bodies) lead to dorsal roots

which expand into rootlets before entering the spinal cord

Question 10

Where do the dorsal rootlets synapse?

Answer 10

May synapse at a dorsal horn interneuron or continue via axons

in the white matter columns towards the brain

Question 11

Describe the Ventral half of the Spinal Roots

Answer 11

Motor rootlets join to form motor roots

Question 12

How do dorsal and ventral roots fuse?

Answer 12

Dorsal and ventral roots fuse laterally to form short spinal nerves

Question 13

Describe Gray Matter Somatotopy

Answer 13

Body representations in four zones (maintain spatial relationships)

Question 14

What are the two visceral representations on the internal aspect?

Answer 14

visceral sensory (VS)

&

visceral motor (VM)

Question 15

What are the two somatic representations on the external aspect?

Answer 15

somatic sensory (SS)

&

somatic motor (SM)

Question 16

Describe White Matter Columns

Answer 16

• White matter columns are fibers that run in three directions - ascending, descending, and transversely
• Divided into three columns (funiculi) -dorsal, ventral, lateral
• Each white matter column contains several fiber tracts

Question 17

What are the three directions that fibers run within White Matter Columns?

Answer 17

ascending

descending

transversely

Question 18

What are the three columns (funiculi) that White Matter Columns are divided into?

Answer 18

dorsal

ventral

lateral

Question 19

What doe the fiber tracts within White Matter Columns reveal?

Answer 19

Fiber tract names reveal their origin and destination

Question 20

What are fiber tracts within White Matter Columns composed of?

Answer 20

Fiber tracts are composed of bundled axons with similar sensory functions