Internal obturator muscle it surrounds the greater part of the obturator foramen, being attached to the inferior pubic ramus and ischium, and at the side to the inner surface of the hip bone below and behind the pelvic brim, reaching from the upper part of the greater sciatic foramen above and behind to the obturator foramen below and in front. It also arises from the pelvic surface of the obturator membrane except in the posterior part, from the tendinous arch which completes the canal for the passage of the obturator vessels and nerve, and to a slight extent from the obturator fascia, which
Mastoid part of the temporal bone the innermost of the mastoid cells by a very thin lamina of bone, and even this may be partly deficient. The "superior border" of the mastoid part is broad and serrated, for articulation with the mastoid angle of the parietal. The "posterior border", also serrated, articulates with the inferior border of the occipital between the lateral angle and jugular process. Anteriorly the mastoid portion is fused with the descending process of the squama above; below it enters into the formation of the ear canal and the tympanic cavity. A section of the mastoid process shows it to be hollowed out