Below the arcuate line of the rectus sheath, the posterior wall of the sheath is deficient. What lies directly posterior to the rectus abdominis muscle at this level?

• A Transversus abdominis aponeurosis
• B Internal oblique aponeurosis
• C Transversalis fascia and extraperitoneal fat ✓
• D Parietal peritoneum alone

Explanation

Below the arcuate line (at the level midway between umbilicus and pubis), all three flat muscle aponeuroses pass anterior to the rectus, leaving only transversalis fascia, extraperitoneal fat and parietal peritoneum behind the muscle. Option D is tempting but omits the transversalis fascia, which is precisely the layer pierced by the inferior epigastric vessels entering this region.

Reference: Gray's Anatomy for Students, 4th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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