Parasympathetic preganglionic neurons originate in which spinal segments?

Parasympathetic preganglionic neurons originate in which spinal segments?

• A. T1-L2
• B. S2-S4
• C. C1-C4
• D. L4-L5

Answer: (B)

Parasympathetic preganglionic neurons originate from brainstem and sacral spinal cord, with the spinal portion located specifically in segments S2 through S4. In these sacral levels, the cell bodies give rise to the pelvic splanchnic nerves that innervate pelvic and lower abdominal organs, sending preganglionic fibers to nearby (intramural) ganglia where they synapse with postganglionic neurons. This contrasts with the sympathetic outflow, which starts in the thoracic and upper lumbar segments (T1-L2), and with other spinal levels that do not contribute to parasympathetic preganglionic output.

Parasympathetic preganglionic neurons originate from brainstem and sacral spinal cord, with the spinal portion located specifically in segments S2 through S4. In these sacral levels, the cell bodies give rise to the pelvic splanchnic nerves that innervate pelvic and lower abdominal organs, sending preganglionic fibers to nearby (intramural) ganglia where they synapse with postganglionic neurons. This contrasts with the sympathetic outflow, which starts in the thoracic and upper lumbar segments (T1-L2), and with other spinal levels that do not contribute to parasympathetic preganglionic output.