| 词条 | Pyramidalis muscle | |
| 释义 |
| Name = Pyramidalis muscle | Latin = musculus pyramidalis | Image = Gray397.png | Caption = Muscles at the front of the abdomen, showing the pyramidalis at the bottom centre. | Origin = pubic symphysis and pubic crest | Insertion = linea alba | Blood = Inferior and superior epigastric arteries | Nerve = Subcostal nerve (T12) | Action = tensing the linea alba }} The pyramidalis is a small triangular muscle, anterior to the rectus abdominis muscle, and contained in the rectus sheath. StructureInferiorly, the pyramidalis attaches to the pelvis in two places: the pubic symphysis and pubic crest, arising by tendinous fibers from the anterior part of the pubis and the anterior pubic ligament. Superiorly, the fleshy portion of the pyramidalis 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. Nerve supplyThe pyramidalis is innervated by the ventral portion of T12. Blood supplyThe inferior and superior epigastric arteries supply blood to this muscle. VariationThe pyramidalis muscle is present in 80% of human population.[1] 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. FunctionThe pyramidalis, when contracting, tenses the linea alba. Clinical significanceWhile making the longitudinal inscision for a classical caesarean section, the pyramidalis is used to determine midline and location of the linea alba. Additional imagesReferences1. ^{{Cite web|url=https://www.britannica.com/list/7-vestigial-features-of-the-human-body|title=7 Vestigial Features of the Human Body|website=Encyclopedia Britannica|language=en|access-date=2017-11-09}} External links
1 : Muscles of the torso |
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