|Origin||pubic symphysis and pubic crest|
|Nerve||Subcostal nerve (T12)|
|Actions||tensing the linea alba|
|Anatomical terms of muscle|
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.
The Pyramidalis muscle 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 also extend higher than the usual level.
The muscle is innervated by the ventral portion of T12.
The inferior and superior epigastric arteries are responsible for supplying blood to this muscle.
While making the longitudinal inscision for a classical caesarean section the pyramidalis is used to determine midline and location of the linea alba.
- Keith Lean Moore; Arthur F. Dalley (1999). Anatomy. Lippincott Williams & Wilkins. p. 180. ISBN 978-0-683-06141-3. Retrieved 1 December 2012.
- -1241120688 at GPnotebook
- Origin, insertion and nerve supply of the muscle at Loyola University Chicago Stritch School of Medicine
- Anatomy photo:35:11-0100 at the SUNY Downstate Medical Center - "Anterior Abdominal Wall: The Pyramidalis Muscle"
- Anatomy image:7283 at the SUNY Downstate Medical Center
- Cross section image: pelvis/pelvis-female-17 - Plastination Laboratory at the Medical University of Vienna
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