Pyramidalis

A small, triangular muscle located in the lower abdominal region.

The pyramidalis is a muscle found in the anterior wall of the abdomen. It originates from the pubic crest and pubic symphysis, and it inserts into the linea alba, a fibrous structure that runs down the midline of the abdomen. This muscle is typically small, and its size can vary among individuals.

Terminologia Anatomica

pyramidalis

System

Muscular system

Function

The primary function of the pyramidalis muscle is to tense the linea alba, aiding in the stabilization of the abdominal wall. While it is not as prominent in action as other abdominal muscles, such as the rectus abdominis or the obliques, it serves a role in abdominal contraction and facilitating movements that require stabilization of the trunk. Its contraction may assist in posture and support during activities that involve the core, particularly in processes such as lifting, bending, or even during respiration, where abdominal pressure changes.

Location

The pyramidalis muscle is situated in the lower anterior part of the abdomen. It lies in front of the rectus abdominis muscle, and its relatively small size allows it to blend seamlessly into the anterior sheath. Positioned at the midpoint between the pubic bone and the umbilicus, it is anchored at the pubic symphysis, extending upward to insert into the linea alba, which runs vertically along the center of the abdomen. This anatomical positioning allows it to contribute effectively to core stability.

Did You Know?

Not everyone has a pyramidalis muscle; it is absent in approximately 20-30% of individuals.
The muscle can vary in size and strength depending on a person's genetics.
The pyramidalis is often a focus in surgical procedures involving the abdominal wall, as its presence can influence techniques.