Remove with great care the levator ani and iliocaudalis of one side, by
cutting first the attachment to the symphysis and the ilium, turning the
muscle mediad, then cutting the attachment to the tail. There are thus
exposed on the lateral wall of the thorax the medial surface of the
obturator internus, craniad of it the pyriformis, caudad of it the
quadratus femoris. Dorsad of these is the abductor caudæ internus.