310 SYNDESMOLOGY 



canal, and descends to be inserted into the posterior surface of the coccyx. This 

 ligament completes the lower and back part of the sacral canal, and is divisible 

 into a short deep portion and a longer superficial part. It is in relation, behind, 

 with the Glutseus maximus. 



The Lateral Sacrococcygeal Ligament (ligamentum sacrococcygeum laterale; inter- 

 transverse ligament).- The lateral sacrococcygeal ligament exists on either side 

 and connects the transverse process of the coccyx to the lower lateral angle of the 

 sacrum ; it completes the foramen for the fifth sacral nerve. 



A disk of fibrocartilage is interposed between the contiguous surfaces of the 

 sacrum and coccyx; it differs from those between the bodies of the vertebrae in 

 that it is thinner, and its central part is firmer in texture. It is somewhat thicker 

 in front and behind than at the sides. Occasionally the coccyx is freely movable 

 on the sacrum, most notably during pregnancy ; in such cases a synovial membrane 

 is present. 



The Interarticular Ligaments are thin bands, which unite the cornua of the two 

 bones. 



The different segments of the coccyx are connected together by the extension 

 downward of the anterior and posterior sacrococcygeal ligaments, thin annular 

 disks of fibrocartilage being interposed between the segments. In the adult male, 

 all the pieces become ossified together at a comparatively early period ; but in the 

 female, this does not commonly occur until a later period of life. At more advanced 

 age the joint between the sacrum and coccyx is obliterated. 



Movements. The movements which take place between the sacrum and coccyx, and between 

 the different pieces of the latter bone, are forward and backward; they are very limited. Their 

 extent increases during pregnancy. 



4. The Pubic Symphysis (symphysis ossium pubis; articulation of the pubic 

 bones] (Fig. 321). The articulation between the pubic bones is an amphiarthro- 

 dial joint, formed between the two oval articular surfaces of the bones. The 

 ligaments of this articulation are: 



The Anterior Pubic. The Superior Pubic. 



The Posterior Pubic. The Arcuate Pubic. 



The Interpubic Fibrocartilaginous Lamina. 



The Anterior Pubic Ligament (Fig. 319). The anterior pubic ligament consists 

 of several superimposed layers, which pass across the front of the articulation. 

 The superficial fibers pass obliquely from one bone to the other, decussating and 

 forming an interlacement with the fibers of the aponeuroses of the Obliqui externi 

 and the medial tendons of origin of the Recti abdominis. The deep fibers pass 

 transversely across the symphysis, and are blended with the fibrocartilaginous 

 lamina. 



The Posterior Pubic Ligament. The posterior pubic ligament consists of a few 

 thin, scattered fibers, which unite the two pubic bones posteriorly. 



The Superior Pubic Ligament (ligamentum pubicum superius) . The superior 

 pubic ligament connects together the two pubic bones superiorly, extending later- 

 ally as far as the pubic tubercles. 



The Arcuate Pubic Ligament (ligamentum arcuatum pubis; inferior pubic or 

 subpubic ligament). The arcuate pubic ligament is a thick, triangular arch of 

 ligamentous fibers, connecting together the two pubic bones below, and forming 

 the upper boundary of the pubic arch. Above, it is blended with the interpubic 

 fibrocartilaginous lamina; laterally, it is attached to the inferior rami of the 

 pubic bones; below, it is free, and is separated from the fascia of the urogenital 

 diaphragm by an opening through which the deep dorsal vein of the penis passes 

 into the pelvis. 



