Pelvis

(from weave, a basin, because it is shaped like a basin used in former times.) The cavity beidw the belly. It is composed of four bones, viz. two O a IN NO MIN AT A, the Sacrum, and Os coccyGis, which see. contains the organs of generation, the bladder, and the rectum. See Uterus, Ovaria, VaGIna, VESICA URINARIA, PROSTATE GLAND, Rectum, . Petvts (Ligaments of). The articulation of the os sacrum with the last lumbar vertebra, and with the o a in no min at a, is strengthened by means of a strong transverse ligament, which pa es from the extremity and lower edge of the last lumbar vertebra, to the posterior and internal surface of the spine of the ihum, Other ligaments are extended posteriorly from the os sacrum to the os ilia on each side, and, from the direction of their fibres, may be called the lateral ligaments. Besides these, there are many shorter ligamentous fibres, which are _seen stretching from the whole circumference of the articulating surfaces of these two bones. But the most remarkable ligaments of the pelvis. are the two sacro-ischiatic ligaments, which are placed towards the posterior and in- - ferior part of the pelvis, One of these may be called the greater, and the other the le er saero-ischiatic ligament. The first of these is attached to the posterior edge of the os sacrum, to the tuberosity of the ilium, and to the first of the three divisions of the os coccygis. _ other pene is inserted into the inner sur- face of the tuberosity of the ischium. At its upper part it is of considerable breadth, after which it becomes narrower, but expands again before its insertion into the ischium, and, ex- tending along the tuberosity of that bone to the Jower branch of the os pubis, where it terminates in a point, forms a kind of falx, one end of which is loose, while the other is fixed te the bone. ‘The le er sacro-ischiatic ligament is somewhat thicker than the former, and is placed obliquely before it. It extends from the transverse proce és of the os sacrum, and the tuberosity of the spine of the ilium on each side, to the spine of the ischium. ‘These two ligaments not only serve to strengthen the articulation of the o a in no min at a with the os sacrum, but to support the weight of the viscera contained in the pelvis, the back and lower part of which is closed by these ligaments. ‘The posterior and external surface of the greater ligament likewise serves for the attachment of some portions of the gluteus maximus and ¢ge-. ‘mini muscles. The symphysis pubis is strengthened internally by a transverse ligament, some of the fibres of which are extended to the obturator ligament. Hig