The posterior pubic ganzent is the most feeble. It is composed of transverse fibres, somewhat scattered, and is remarkable in being raised by the posterior border of the pubic fibro-car tilage into a vertical ridge, in old persons often very evident to the touch. It gives attachment to the superior true ligaments of the bladder, and the anterior fibres of the levator ani muscle.
The superior pubic ligament (e) is formed by a thick, smooth la)er of fibres often raised by a central ridge like the posterior, passing between the crests of the pubes, the super ficial fibres extending over the greater part of the crests, and giving origin to the recti ab dominales and pyramidales abdominal muscles, and linea alba.
The inferior or sub-pubic ligament, (liga mentum arcuatum, f) is the most povterful, passing from one descending ramus of the pubis to the other in an arched form. Its place of attachment to the pubis is often a well-marked surface, triangular, with the base upward, and half an inch in depth, cor responding in this respect to the outline of the section of this ligament. This ligament and the anterior are the most intimately con nected with the fibro-cartilage of the joint. It unites below with the two layers of the deep perinea' fascia or triangular ligament, be tween which it gives origin to the vertical compressores urethra, and forms the superior boundary of the pubic arch, the apex of which it rounds off and smoothens.
The movements of the pubic symphysis are confined to a slightly yielding sliding motion giving elasticity to the resistance of the pelvic ring.
The obturator or thyroid membrane (g) is a fascial aponeurosis rather than a ligament, which closes in the oval foramen of that name. It is composed of layers of fibres, intermin gling in a circular direction, and generally congregated more in some places than others. These are attached to the rough narrow bor der of the descending branch of the ischium externally, but at the internal half of its cir cumference it is attached to the posterior sur face of the ascending branch of the ischium and descending branch of the pubis, overlap ping in this situation the borders of these bones posteriorly. Superiorly, it is inter rupted by passing over from one edge of the sub-pubic notch to the other, so as to form the lower boundary of a foramen for the pas sage of the obturator nerves and vessels. Opposite the cotyloid notch its fibres are continued into the capsular ligament invest ing the hip joint. By its anterior surface, it gives attachment to the obturator external muscle, and, by its posterior surface, to the internal muscle of the same name. It is some times deficient in one or more places.