13), consisting of the sacrum (already described) and the pelvic arch, namely ilium, ischium and pubis, it follows that only birds and mammals possess a pelvis proper, whilst such is entirely absent in the Amphibia and in reptiles with the exception of some of the Dinosaurs.
In front of the acetabulum a thick process of the ilium descends to meet the pubis, and a similar process behind meets the ischium.
The ischium and postacetabular ilium originally enclose the ischiadic notch or incisura ischiadica.
The shaft of the pubis runs parallel with that of the ischium, with which it is connected by a short ligamentous or bony bridge; this cuts off from the long incisura pubo-ischiadica a proximal portion, the foramen obturatum, for the passage of the obturator nerve.
Ilium; Is, ischium; Pb, pubis; d.l, dorso-lumbar vertebrae; Cd, caudal vertebrae; Am, acetabulum.
Maxillary bordering the mouth, forming sutures with the premaxillary, prefrontal and frontal, toothless; lower jaw toothed; pubis and ischium present, the latter forming a symphysis: Glauconiidae.
Posterior superior iliac spine Ureter Great sciatic notch Vas deferens; Spine of ischium Vas deferens Seminal vesicle Bladder wall Levator ani Prostate 9, ?
Ischio-rectal fossa Tuberosity of ischium Gluteus maximus The vesiculae seminales are sac-like diverticula, one on each side, from the lower part of the ampullae of the vasa deferentia.
Posterior superior iliac spine Cut end of rectum Apex of sacrum Great sciatic notch Ureter Peritoneum Spine of ischium Bladder wall Seminal vesicle Tuberosity of ischium Ischio-rectal fossa Cut end of rectum External sphincter ani Gluteus maximus better seen in young the prostate the urethra runs more forward for about threequarters of an inch, lying between the two layers of the triangular From C. S.
ral ribs; Il, ilium; Is, ischium.
The pelvic arch of some of the Stegocephalia contained a well ossified pubic element, whilst in all other batrachians only the ilium, or the ilium and the ischium are ossified.
In the Ecaudata the ilium is greatly elongated and the pubis and ischium are flattened, discoidal, and closely applied to their fellows by their inner surfaces; the pelvic girdle looks like a pair of tongs.
The clitoris is the representative of the penis, and consists of two corpora cavernosa which posteriorly diverge to form the crura clitoridis, and are attached to the ischium; the organ is about an inch and a half long, and ends anteriorly in a rudimentary glans which is covered by the junction of the labia minora; this junction forms the prepuce of the clitoris.
Posteriorly, at what is known as the root of the penis, the two corpora cavernosa diverge, become more and more fibrous in structure, and are attached on each side to the rami of the ischium, while the corpus spongiosum becomes more vascular and enlarges to form the bulb.
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