Origin: Spine of the ischium
Insertion: Obturator internus tendon
Nerve: Sacral plexus (S1, S2, S3)
Action: Rotates laterally thigh
The Gemelli are two small muscular fasciculi, accessories to the tendon of the Obturator internus which is received into a groove between them.
The Gemellus superior, the smaller of the two, arises from the outer surface of the spine of the ischium, blends with the upper part of the tendon of the Obturator internus, and isinserted with it into the medial surface of the greater trochanter. It is sometimes wanting.