Human Movement Science & Functional Anatomy of the:

Rectus Abdominis (and Pyramidalis)

by Brent Brookbush DPT, PT, COMT, MS, PES, CES, CSCS, ACSM H/FS

 Image of a cadaver with rectus abdominis highlighted in purple. Rectus Abdominis

What’s in a name?

  • Rectus Abdominis

    • Rectus – rectify (v.) c.1400, from Old French rectifier, literally “to make straight” (14c.), from Late Latin rectificare “make right,” from Latin rectus “straight” (see right (adj.1)) + root of facere “to make” (see factitious). Related: Rectified; rectifying. (Etymology Online)
    • Abdominis – abdomen (n.) 1540s, “belly fat,” from Latin abdomen “belly,” which is of unknown origin, perhaps from abdere “conceal,” with a sense of “concealment of the viscera,” or else “what is concealed” by proper dress. (Etymology Online)

      • "the straight muscle that conceals the abdominal viscera"

  • Pyramidialis

    • pyramid (n.) - 1550s (earlier in Latin form piramis, late 14c.), from French pyramide (Old French piramide "obelisk, stela," 12c.), from Latin pyramides, plural of pyramis "one of the pyramids of Egypt," from Greek pyramis (plural pyramides) "a pyramid," apparently an alteration of Egyptian pimar "pyramid." Financial sense is from 1911. Related: Pyramidal. (Etymology Online)
    • -al (1) suffix forming adjectives from nouns or other adjectives, "of, like, related to, pertaining to," Middle English -al, -el, from French or directly from Latin -alis (see -al (2)). (Etymology Online)

      • A muscle shaped like a pyramid

Cadaver disection with professor tracing the pyramidalis muscle just medial to the lowest portion of the rectus abdominis. Pyramidalis (being traced with surgical tool in image) - https://academic.amc.edu/martino/grossanatomy/site/medical/lab%20manual/gastrointestinal/Dissections/Anterior%20Abd%20Wall/Anterior%20Abd%20Wall%2034.html

Attachments and Innervation

Rectus Abdominis

  • Origin: The tendons of each individual rectus abdominis attach to