The pyramidalis muscle is a small triangular muscle located superficially to the rectus abdominis muscle.

It is located inferiorly in the anterior abdominal wall with its base on the pubic bone, and the apex of the triangle attached to the linea alba.

Origin: pubic crest and pubic symphysis.

Insertion: linea alba - in midway between the umbilicus and pubic bone.

Action: tenses the linea alba.

Innervation: ventral ramus of the spinal nerve T12 (subcostal nerve).

Blood supply: inferior epigastric artery.

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Pyramidalis muscle