CHAPTER VII. 

 DISSECTION OF THE PELVIS. 



SECTION I. 



THE CAVITY OF THE PELVIS. 



Dissection. For the convenience of examination the pelvis 

 should now be detached from the rest of the trunk by cutting 

 through the disc between the third and fourth lumbar vertebral 

 and severing the soft parts and ligamentous tissues as required. 

 The lower limbs will already have been removed. 



The cavity of the pelvis is the part of the general abdominal 

 space situate below the brim of the true pelvis. 



Boundaries. The space is surrounded by the firm ring of the pelvic 

 behind and bones : it is bounded behind by the sacrum and coccyx, with the pyri- 

 formes muscles and the sacro-sciatic ligaments ; and laterally and in 

 front by the hip-bones covered by the internal obturator muscles. 



Inferiorly, or towards the perineum, the cavity is limited by the 

 fascia passing from the wall to the viscera, and by the levatores ani 

 and coccygei muscles : it is only in this direction, where the 

 bounding structures are to some extent moveable, that the size of 

 the space can be appreciably altered. 



Contents. In the pelvis are contained the urinary bladder with 

 the beginning of the urethra, the lower end of the large intestine or 

 the rectum, and some of the generative organs, according to the 

 sex. The viscera are supplied with vessels, nerves, and lymphatics ; 

 and the serous membrane is reflected over them. 



Definition 

 and situa- 

 tion. 

 Boundaries ; 



before 



below. 



Contents. 



The peri- 

 toneum. 



THE PERITONEUM, THE PELVIC FASCIA AND MUSCLES OF THE OUTLET. 



Directions. The student will now in a good light make "a detailed 

 examination of the cavity of the pelvis and of its lining peritoneum. 



*Foss.E OF THE PELVIS (fig. 141). The pelvic colon terminates 

 in the rectum at the back of the pelvis opposite the third sacral 

 vertebra, and at that point the bowel ceases to have a mesentery. 

 The peritoneum invests the sides and front of the rectum in its 

 upper third, and then, leaving its sides, continues down the front of 

 the middle third of the bowel, when leaving it altogether, it is 

 reflected on to the upper part of the seminal vesicles and thence on 

 to the upper surface of the bladder in the male, or on to the upper 



* For the subjoined description the Editor is much indebted to work of 

 Dixon and Birmingham. 



