Pyramidalis innervation is supplied by which nerve?

Pyramidalis innervation is supplied by which nerve?

• A. Subcostal nerve
• B. Iliohypogastric nerve
• C. Ilioinguinal nerve
• D. Genitofemoral nerve

Answer: (A)

The pyramidalis is a small muscle on the front wall of the abdomen, and its motor supply comes from the subcostal nerve, the T12 ventral ramus. This nerve travels along the lower border of the 12th rib and provides muscular branches to the pyramidalis as well as nearby abdominal wall muscles. The other nerves listed—iliohypogastric and ilioinguinal (both L1) supply internal oblique and transversus abdominis and provide cutaneous innervation to the lower abdomen and groin, while the genitofemoral nerve (L1–L2) mainly innervates the cremaster and skin of the anterior thigh. Thus, the subcostal nerve best fits as the innervation of pyramidalis.

The pyramidalis is a small muscle on the front wall of the abdomen, and its motor supply comes from the subcostal nerve, the T12 ventral ramus. This nerve travels along the lower border of the 12th rib and provides muscular branches to the pyramidalis as well as nearby abdominal wall muscles. The other nerves listed—iliohypogastric and ilioinguinal (both L1) supply internal oblique and transversus abdominis and provide cutaneous innervation to the lower abdomen and groin, while the genitofemoral nerve (L1–L2) mainly innervates the cremaster and skin of the anterior thigh. Thus, the subcostal nerve best fits as the innervation of pyramidalis.