pyramidalis /piram′idā″lis/ , one of a pair of anterolateral muscles of the abdomen, contained in the lower end of the sheath of the rectus abdominis, which arises from the crest of the pubis and is inserted into the linea alba upward about halfway to the navel. It is innervated by a branch of the twelfth thoracic nerve and functions to tense the linea alba. Compare rectus abdominis, transversus abdominis.
