The following structures pass through the greater sciatic foramen except?

NHM UP Staff Nurse - 2016

Applied Anatomy

Easy

Appeared in: NHM UP Staff Nurse - 2016

Explanation

The obturator internus tendon is the correct answer because it is the only structure listed that does not pass through the greater sciatic foramen.
It passes through the lesser sciatic foramen to insert on the greater trochanter of the femur, acting as a lateral rotator of the hip.
The greater sciatic foramen serves as a major conduit for structures traveling from the true pelvis into the gluteal region.

Option A: This is incorrect because the superior gluteal artery is a key structure that passes through the greater sciatic foramen, superior to the piriformis muscle, to supply the gluteal muscles.
Option B: This is incorrect because the sciatic nerve, the largest nerve in the body, famously passes through the greater sciatic foramen, inferior to the piriformis muscle, to enter the posterior thigh.
Option D: This is incorrect because the pudendal nerve does pass through the greater sciatic foramen as it exits the pelvis. It then loops around the ischial spine to re-enter the perineum via the lesser sciatic foramen.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Anatomy of the gluteal region, specifically the structures passing through the greater and lesser sciatic foramina as background academic context rather than a clinical decision trigger.
Precise knowledge of the structures passing through the greater sciatic foramen is critical for administering intramuscular (IM) injections in the dorsogluteal site. Injections must be given in the upper outer quadrant to avoid injury to the sciatic nerve.
The path of the pudendal nerve through the greater and lesser sciatic foramina is the anatomical basis for a pudendal nerve block, a local anesthetic procedure used to provide pain relief during the second stage of labor and for perineal repairs.
What if the question asked which structure passes through both the greater and lesser sciatic foramina? The answer would include the pudendal nerve, internal pudendal vessels, and the nerve to the obturator internus.

How to Approach the Question

First, identify the negative framing of the question by spotting the word 'except'. This means you are looking for the one option that does not fit the condition described.
The core of the question is anatomical recall: What structures pass through the greater sciatic foramen?
Systematically review each option against your knowledge of pelvic anatomy.
Recall that the superior gluteal artery and sciatic nerve are classic structures that pass through the greater sciatic foramen.
Remember the unique path of the pudendal nerve, which exits through the greater foramen and re-enters through the lesser foramen. Since it does pass through the greater foramen, it's not the exception.
Identify the obturator internus tendon as the structure that passes through the lesser sciatic foramen, making it the correct answer to this 'except' question.

Concept Tested & Keywords

Concept Tested: Anatomy of the gluteal region, specifically the structures passing through the greater and lesser sciatic foramina.
Stem keywords: greater sciatic foramen, structures, pass through
Lead-in keywords: except
Negative lead-in flag: The question asks for the structure that is an EXCEPTION.

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E6 Anatomy BDChaurasia V2 10e Part 1 pp. 97-99, 98-100

E6 Gynecology Williams p. 381-394