INTRODUCTION. Iliocapsularis is a variation of the iliacus muscle reported as originating from the ASIS and inserting into the lesser trochanter of the femur. While the function of this muscle is undecided, it has been hypothesized to be a dynamic stabilizer of the hip.

RESOURCES. Twenty-four cadaveric hips were dissected at Philadelphia College of Osteopathic Medicine-GA Campus’ Anatomy Lab. To preserve any possible iliocapsularis muscles, the dissection was performed with a lateral-medial incision from 1 inch above the ASIS across the iliac fossa cutting both the iliacus and psoas. The inferior portion of the iliacus and psoas muscles were reflected from the ilium allowing access to the hip joint capsule.

DESCRIPTION. Of the 24 hips dissected only three iliocapsularis muscles were discovered. Each iliocapsularis was positioned under the iliopsoas within a separate fascial compartment from the iliacus muscle. The attachments of two of the iliocapsularis muscles were not consistent with the documented literature. Variation one originated from between the ASIS and AIIS, blended into the iliacus muscle, and inserted into the lesser trochanter of the femur. Variation two originated from the ilium inferior and medial to the ASIS and bifurcated into two bands with the lateral band inserting into the vastus intermedius muscle and the medial band inserting into the shaft of the femur and lesser trochanter.

SIGNIFICANCE. Finding three iliocapsularis muscles out of 24 hips confirm that this muscle is not a commonality in all individuals, contradicting literature declaring it as such. Knowledge of hip anatomical variations can be helpful in differential diagnosis of anterior hip dysfunctions. Since dynamic hip stabilization will be altered in the presence or absence of the iliocapsularis muscle, as well as by variations in origin, insertion, and line of pull of this muscle; the iliocapsularis should be considered when assessing hip stability.