Pyramidalis muscle

This Kenhub tutorial discusses the pyramidalis muscle, an anterior abdominal muscle involved in tensing the abdominal wall. It covers the muscle's anatomy, including its triangular shape, location, and innervation by the subcostal nerve. The tutorial also touches on the evolutionary aspect of the pyramidalis, noting its rudimentary nature and its presence in some monotremes and marsupials. The video concludes by encouraging viewers to explore more resources on Kenhub for a comprehensive understanding of human anatomy.

Explain the evolutionary significance of the pyramidalis muscle in mammals.

Why might the pyramidalis muscle not be present in all humans?