The preganglionic parasympathetic fibres that supply the distal colon, rectum, and bladder originate from which spinal segments?
- A T1 to L2
- B S2 to S4 ✓
- C L1 to L3
- D S1 to S5
Correct answer: B. S2 to S4
Explanation
The sacral outflow (S2 to S4) gives rise to the pelvic splanchnic nerves, which carry preganglionic parasympathetic fibres to the hindgut structures supplied beyond the splenic flexure, plus the rectum and bladder. The cranial outflow via the vagus reaches only up to the mid-transverse colon. T1 to L2 is the thoracolumbar sympathetic outflow, a common trap.
Reference: Gray's Anatomy for Students, 4th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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