OSTEOLOGY. S3 



quadratus luuiborum. Externally gluteus maximus is 

 attached to it, and from its inferior tubercles runs the 

 common tendon of tensor vaginae and gluteus externus. 

 The siqjerior angle is the supero-posterior spinous process, 

 it is elongated, flattened from within outwards, and sujdo- 

 riorly is curled slightly outvvards. To it runs the superior 

 ilio-sacral ligament, from its posterior margin the inferior 

 ilio-sacral ligament. To its inner surface is attached 

 longissimus dorsi, and to its external surface gluteus 

 maximus ; while gluteus externus, in some cases, seems to 

 arise from its summit. The inferior angle becomes rounded 

 in forming the neck, which is convex, and below dilates to 

 form the anterior part of the acetabulum inferiorly, the 

 union with the neck of the ischium, externo- superiorly, the 

 junction with the os pubis antero-internally. The external 

 surface of the ilium is called the dorsum, and is concave, 

 looking upwards, outwards, and backwards. It becomes 

 convex in forming the neck. Superiorly to the upper 

 margin it affords attachment to gluteus maximus, and this 

 muscle is firmly attached to it as far as a crescentic groove, 

 running across its neck where gluteus internus commences, 

 and becomes attached as far down as the acetabulum. The 

 margin connecting the anterior and superior angles is slightly 

 concave, and is rough and thickened. It is termed the 

 crista, and affords firm attachment to the tendinous struc- 

 ture of longissimus dorsi. The anterior 7nargin is concave, 

 and looks downwards and outwards, it is smooth, affords 

 internally attachment to iliacus, externally to the glutei 

 muscles, and inferiorly at the neck becomes widened, 

 forming two roughened fossae separated by a smooth space. 

 To these, one of which is inclined to the dorsum, the other 

 to the venter surface, are attached the two heads of rectus 

 f emoris ; between them is a small quantity of fat. Below this 

 ilio-femoralis arises, above it psoas parvus is inserted. The 

 jposterior margin is divided into three parts. The superior 

 third gives attachment to the inferior ilio-sacral ligament, 

 the middle is smooth for passage of gluteal vessels and 

 nerves round it from within outwards, the inferior forms 

 a very sharp prominent ridge continued on to the neck of 

 the ischium, to which the sacro- sciatic ligament is attached. 

 This is the ischiatic spine, and externally is continuous with 

 a small but very rough space for attachment of part of 

 gluteus internus. The internal surface of the ilium is 



