Pyramidalis muscle

Gray's anatomy image 235

== Pyramidalis muscle ==

The Pyramidalis muscle is a small, triangular muscle located in the lower part of the abdomen. It is situated in front of the rectus abdominis muscle and within the rectus sheath. The muscle is often absent in some individuals, with studies suggesting that it is missing in approximately 20% of the population.

Anatomy

The Pyramidalis muscle originates from the pubic symphysis and the pubic crest. It inserts into the linea alba, a fibrous structure that runs down the midline of the abdomen. The muscle is innervated by the subcostal nerve, which is derived from the twelfth thoracic nerve (T12).

Function

The primary function of the Pyramidalis muscle is to tense the linea alba. This action helps to support the anterior abdominal wall and may assist in the stabilization of the rectus abdominis muscle during movements of the trunk.

Clinical Significance

The Pyramidalis muscle is of minor clinical significance due to its small size and variable presence. However, it can be of interest in certain surgical procedures involving the lower abdomen, such as cesarean sections or hernia repairs. Its presence or absence can also be noted during abdominal imaging studies.

Related Pages

• Rectus abdominis muscle
• Linea alba
• Rectus sheath
• Pubic symphysis
• Subcostal nerve
• Abdominal wall