Pyramidalis muscle
Citation, DOI, disclosures and article data
Citation:
Vasu B, Hacking C, Kang O, et al. Pyramidalis muscle. Reference article, Radiopaedia.org (Accessed on 13 Jan 2025) https://doi.org/10.53347/rID-27059
rID:
27059
Article created:
19 Jan 2014,
Balaji Vasu
Disclosures:
At the time the article was created Balaji Vasu had no recorded disclosures.
View Balaji Vasu's current disclosures
Last revised:
Disclosures:
At the time the article was last revised Craig Hacking had no recorded disclosures.
View Craig Hacking's current disclosures
Revisions:
4 times, by
4 contributors -
see full revision history and disclosures
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Synonyms:
- Pyrimidalis
The pyrimidalis muscle is a small paired triangular muscle of the lower anterior abdominal wall that is rudimentary and variably present in humans.
On this page:
Summary
- origin: pubic symphysis and pubic crest
- insertion: linea alba at the midway point between umbilicus and pubis
- innervation: ventral T12 spinal nerve (variable)
- action: uncertain; thought to tense the linea alba
Gross anatomy
The pyramidalis muscle has its origin from the bony pelvis, where it is attached to the pubic symphysis and pubic crest. The fibers run superiorly and medially to insert into the linea alba at a point midway between umbilicus and pubis.
It lies within the rectus sheath, anterior to the rectus abdominis muscle.
Innervation
The nerve supply to the muscle is from ventral part of T12 spinal segment although this has been reported as being quite variable 3.
Variant anatomy
- absent in ~20% of cases (reported range of absence is 10-70%) 3
- may be present only unilaterally
References
- 1. Gillenwater JY, Grayhack JT, Howards SS et-al. Adult and pediatric urology. Lippincott Williams & Wilkins. ISBN:0781732204. Read it at Google Books - Find it at Amazon
- 2. Greenfield's Surgery: Scientific Principles & Practice. Lippincott Williams & Wilkins. ISBN:1605473553. Read it at Google Books - Find it at Amazon
- 3. Lovering RM, Anderson LD. Architecture and fiber type of the pyramidalis muscle. Anat Sci Int. 2008;83 (4): 294-7. doi:10.1111/j.1447-073X.2007.00226.x - Free text at pubmed - Pubmed citation
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