434 APPLIED ANATOMY. 



The cavity of the pelvis is narrowed somewhat by the soft parts on its sides. 

 The blood-vessels, nerves, and obturator muscles are placed laterally and so usually 

 escape injury. In pregnancy the venous flow is most often interfered with. The 

 first evidence of this is the dusky hue of the vagina; hemorrhoids and varicosities of 

 the veins of the external genitals and lower extremities are common. The rectum 

 and bladder being placed more anteroposteriorly, interference with their functions is 

 frequent. The peculiarities of the female pelvis are evident from birth and are not 

 solely acquired with age. 



Pelvic Walls. On looking laterally at the inside of the pelvis, the iliopecti- 

 neal line is seen separating the abdominal from the pelvic portion. On the iliac or 

 abdominal portion lie the iliacus and psoas muscles. Below the iliopectineal line 

 anteriorly is the body of the pubis with the symphysis in the median line. The 

 descending ramus of the pubis passes down to be continuous with the ramus of the 

 ischiurn to the tuberosity. A short distance above the tuberosity is the spine of the 

 ischium. Posteriorly are the five vertebrae of the sacrum and the four of the coccyx. 

 Passing upward from the tuberosity of the ischium to the sacrum is the great sacro- 

 sciatic ligament (ligamentum sacrotuberosiim) ; passing backward from the spine of 

 the ischium to the sacrum and coccyx is the Sesser sacrosciatic ligament (ligamentum 

 sacrospinosmri) . The large opening above the lesser sacrosciatic ligament is the great 



Iliac fossa and iliac muscle 

 Tensor fasciae femoris 

 Anterior superior spine 

 and sartorius muscle 



Anterior inferior spine 

 and rectus femoris muscle 



Iliopectineal line 



Spine of pubis 

 Crest of pubis 

 Symphysis 

 Levator ani muscle 



-Transverse perineal muscle 

 Coccygeus Obturator internus 



FIG. 441. View of the pelvis from the inside. 



sacrosciatic foramen. Through it pass the pyriformis muscle, with the gluteal vessels 

 and superior gluteal nerve above, and, below, the sciatic vessels and nerves, the 

 internal pudic vessels and nerve, the inferior gluteal nerve, and the nerves to the 

 obturator internus and quadratus femoris. The smaller opening below the lesser 

 sacrosciatic ligament is the lesser sacrosciatic foramen, through which passes the 

 tendon of the obturator internus, the nerve to it, and the internal pudic vessels and 

 nerve. In front of these two foramina is a third, the obturator. It is closed by a 

 membrane except at its upper inner portion, which gives exit to the obturator vessels 

 and nerve. Attached to the inner surface of this membrane is the origin of the 

 obturator internus muscle and to its outer surface the obturator externus (Fig. 441). 

 Pelvic Floor. The pelvic outlet is closed by two muscles, the levator ani and 

 coccygeus. These on each side constitute the pelvic floor. The coccygeus is 

 a comparatively small muscle passing from the spine of the ischium to the coccyx. 

 The levator ani is the main muscle which supports and retains the pelvic and 

 abdominal viscera in their normal positions. It arises from the " white line" which 

 is a thickening of the pelvic fascia extending from the posterior surface of the pubes 

 in front to the spine of the ischium behind and descends to be attached to the 

 coccyx posteriorly, then around the lower portion of the rectum just above the exter- 

 nal sphincter and, farther front, surrounds the vagina of the female or the prostate 

 gland in the male. The part surrounding the prostate has been called the levator 



