The Pyramidalis is a paired, triangular muscle located on the anterior abdominal wall, situated superficial to the Rectus Abdominis muscle. It is responsible for tensing the Linea Alba.
The pyramidalis originates from the pubic crest and pubic symphyse before inserting onto the Linea Alba.
The pyramidalis serves to tense the Linea Alba, maintaining the integrity of the abdominal wall.
The pyramidalis muscle is innervated by the Subcostal Nerve (T12).
The pyramidalis muscle is supplied by the Inferior Epigastric Artery.
The pyramidalis muscle is a small and relatively unimportant muscle of the abdominal wall. It serves to tense the the Linea Alba, a structure important for maintaining tension between the left and right side of the abdominal wall. When looking at a patient’s abdomen it can be difficult to differentiate the pyramidalis muscle from other muscles, given its small size. The pyramidalis muscle is typically not a primary site of pathology, but a number of conditions including hernias, diverticulitis, and ascites can cause the muscle to become strained, inflamed, and/or swollen. In rare instances, the pyramidalis muscle can be totally absent; an absence may be congenital or caused by prior surgical trauma.
It is important to recognize the pyramidalis muscle for its unusual attachments, actions, and its role in maintaining the tension of the abdominal wall. Knowledge of this muscle’s anatomy and function can be useful to clinicians when evaluating the abdominal wall for abnormalities.
