Which leaves the pelvis ?
**Core Concept**
The question requires knowledge of pelvic anatomy, specifically the structures that exit the pelvic cavity. This involves understanding the boundaries and openings of the pelvis, including the greater and lesser sciatic foramina.
**Why the Correct Answer is Right**
The correct answer is related to the anatomical pathways that allow nerves and vessels to exit the pelvis. The **obturator nerve** and **vessels** exit the pelvis through the **obturator canal**, but the question seems to be about which option directly leaves the pelvis, implying a structure that passes through one of the pelvic openings.
**Why Each Wrong Option is Incorrect**
**Option A:** This choice is incorrect because it does not accurately describe a structure that leaves the pelvis in the context provided.
**Option B:** Similarly, this option does not fit the criteria of leaving the pelvis through one of its defined anatomical pathways.
**Option C:** This choice is also incorrect as it does not correspond with the known anatomical structures that exit the pelvis.
**Clinical Pearl / High-Yield Fact**
A key point to remember is that the **sciatic nerve** exits the pelvis through the **greater sciatic foramen**, below the **piriformis muscle**. This is crucial for understanding the anatomy relevant to the question.
**Correct Answer:** D. The pudendal nerve and internal pudendal vessels temporarily leave the pelvis between the piriformis and ischial spine to re-enter through the lesser sciatic foramen.