trochanteric fossa

The width and depth of the trochanteric fossa varies taxonomically.

The posterior border is very prominent and appears as a free, rounded edge, which bounds the back part of the trochanteric fossa.

In these taxa, the trochanteric fossa is the insertion point for the puboischiofemoralis externus muscle.

The trochanteric fossa is a deep depression bounded posteriorly by the intertrochanteric crest on medial surface of the greater trochanter.

Anterior and superior to the trochanteric fossa is a shallower depression known as the Unnamed Fossa.

Obturator externus: originates from the ventral side of the pubis ad ischium, inserts into the trochanteric fossa.

The obturators have their origins on either sides of the obturator foramen and are inserted into the trochanteric fossa on the femur.

Gemellus: a deep muscle that originates on lateral side of the ischium, inserts into the trochanteric fossa and ridge of the ischium.

The obturator internus originates on the pelvis on the obturator foramen and its membrane, passes through the lesser sciatic foramen, and is inserted on the trochanteric fossa of the femur.

In reptiliomorphs such as Seymouria or Diadectes and basal reptiles such as Pareiasaurus, the trochanteric fossa (also known as the intertrochanteric fossa) is a very large depression on the ventral/posterior side of the femur.

The deep branch runs obliquely upward upon the tendon of the obturator externus and in front of the quadratus femoris toward the trochanteric fossa, where it anastomoses with twigs from the superior gluteal artery and inferior gluteal artery.

The fibers converge and pass posterolateral and upward, and end in a tendon which runs across the back of the neck of the femur and lower part of the capsule of the hip joint and is inserted into the trochanteric fossa of the femur.