Structure passing through both greater and lesser sciatic foramen is ?
**Core Concept**
The question is testing knowledge of the anatomy of the sciatic foramina, specifically the structures that pass through both greater and lesser sciatic foramina. The sciatic foramina are two openings in the pelvis through which nerves and vessels pass.
**Why the Correct Answer is Right**
The correct answer is the pudendal nerve, which originates from the sacral nerve roots (S2-S4) and passes through the greater sciatic foramen, then re-enters the pelvis through the lesser sciatic foramen to supply the perineal region. The pudendal nerve is responsible for controlling the muscles of the pelvic floor, including the external anal sphincter and the external urethral sphincter.
**Why Each Wrong Option is Incorrect**
* **Option A:** The sciatic nerve is a major nerve that passes through the greater sciatic foramen, but it does not re-enter the pelvis through the lesser sciatic foramen.
* **Option B:** The obturator nerve passes through the obturator canal, which is a separate opening in the pelvis, and does not pass through both sciatic foramina.
* **Option D:** The ilioinguinal nerve passes through the inguinal canal, which is a separate opening in the abdominal wall, and does not pass through both sciatic foramina.
**Clinical Pearl / High-Yield Fact**
The pudendal nerve is often tested on exams because of its unique course through the sciatic foramina, making it a key structure to know in pelvic anatomy.
**Correct Answer:** C.