Human Movement Science & Functional Anatomy of the:
by Brent Brookbush MS, PES, CES, CSCS, ACSM H/FS
What's in a name?
- Iliacus - Derivation of the latin root "Ilia" referencing flanks or entrails. The medical or anatomical reference is a more modern derivation of this root, specifically referring to structures related to, or in proximity of the "Ilium" or "Iliac" - in the case of the Iliacus, the bone of origin.
- The "iliacus" and "psoas" are often referred to as a singular structure known as the "iliopsoas" - likely due to their common tendon and insertion. However, this article will address some stark differences, suggesting that these muscles should be considered separately.
- Origin: Superior 2/3 or the iliac fossa, internal lip of the iliac crest, iliolumbar and ventral sacroiliac ligaments and ala of the sacrum (11).
- Insertion: Lateral side of the psoas tendon investing with fibers inserting just Lateral and distal to those of the psoas on the lesser trochanter of the femur (11).
- The iliacus is bordered posteriorly by the ilium, as the "iliac fossa" referenced above is a mild depression that encompasses nearly the entirety of the internal face of the ilium. Anteriorly, the psoas borders the medial portion of the iliacus, the Lateral fibers abut the perotineum. As the muscle courses inferiorly it passes just anterior the pubic ramus at the iliopectineal eminence, posterior to the inguinal ligament and