Topographical anatomy of the albino rat's ischiotrochanteric muscle group

The obturator internus, gemelli, and quadratus femoris muscles are thought to be postural muscles. Thus, they are in the focus of research. Although these muscles are described in other species, detailed descriptions are still lacking for the albino rat. We hypothesized that the rat's ischiotrochanteric muscle group is comparable to that of humans. We aimed to provide a detailed description, and to compare the rat's condition with other species including humans. Both hind limbs of 30 adult male formalin-fixed albino rats were carefully dissected and photo documented. Our results were then compared with data for other species and descriptions of human anatomy. The gemellus muscle was one single muscle mass, originating from the lesser sciatic notch and an unnamed groove on the dorsal aspect of the ischium. The obturator internus muscle arose from the inner aspect of the tabula of ischium. Both muscles formed a continuum and inserted as one complex on the medial aspect of the greater trochanter. The quadratus femoris muscle originated from the outer aspect of the tabula of ischium and inserted on the distal portion of the intertrochanteric crest, and the dorsal aspect of the lesser trochanter. Despite minor differences, the topographical conditions of these muscles are comparable between rats and other mammals including humans.