Henry Gray (18251861). Anatomy of the Human Body. 1918.
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 Glutæus maximus.
The Lateral Sacrococcygeal Ligament (ligamentum sacrococcygeum laterale; intertransverse 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 vertebræ 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 amphiarthrodial joint, formed between the two oval articular surfaces of the bones. The ligaments of this articulation are:
The Anterior Pubic.
The Posterior Pubic.
The Superior 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 laterally 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.