|The Transversus abdominis, Rectus abdominis, and Pyramidalis. (Pyramidalis labeled at bottom center.)|
|Gray's||subject #118 416|
|Origin||pubic symphysis and pubic crest|
|Nerve:||Subcostal nerve (T12)|
|Action:||tensing the linea alba|
Attachments and actions
Superiorly, the fleshy portion of the muscle passes upward, diminishing in size as it ascends, and ends by a pointed extremity which is inserted into the linea alba, midway between the umbilicus and pubis.
Therefore, when contracting, it has the function of tensing the linea alba.
It is absent in 20% of normal humans.
This muscle may be absent on one or both sides; the lower end of the rectus then becomes proportionately increased in size.
Occasionally it is double on one side, and the muscles of the two sides are sometimes of unequal size.
It may extend higher than the usual level.
The muscle is innervated by the ventral portion of T12.
- -1241120688 at GPnotebook
- LUC pyr
- SUNY Labs 35:11-0100 - "Anterior Abdominal Wall: The Pyramidalis Muscle"
- SUNY Anatomy Image 7283
- Cross section at UV pelvis/pelvis-female-17