Innominate bone

From this second junction or plexus beneath the gluteus maximum muscle, are given usually three cutaneous nerves to the integument of the buttock: all these perforate the gluteus; one being found near the posterior superior spine of the innominate bone, another, the largest, near the end of the sacrum, and the remaining one being intermediate between the other two.

On its sides, in the upper two-thirds of its extent, the sacrum is closely united to the two pelvic or innominate''' bones, which, together with it, enclose a basin or cavity, called the pelvis. Examined in early life, each innominate bone is seen to consist of three parts, which meet at the articular cup, called the acetabulum, for the head of the thigh bone.

A partial innominate bone (Z8623) is known from the original collections[…], but it was probably from a juvenile individual, since the sutures between the ischium and iliac portions of the innominate are not completely fused up; the suture is unfused even within the acetabulum.