1920 



HUMAN ANATOMY. 



the pelvic fascia (which is reflected from the gland near its upper end), favoring the 

 development of pelvic cellulitis from urinary infiltration (page 1933^ ; or it might 

 divide the neck of the bladder and open up the recto-vesical fossa with the same 

 results ; or, if the prostatic incision were too extensive and too vertical, it might 

 wound the ejaculatory ducts or seminal vesicles. The incision — which is made after 

 a grooved staff has been introduced into the bladder, and while it is held in place by 

 an assistant — accordingly begins at a point a little to the left of the raphe and a little 

 posterior to the perineal centre — i.e., about one to one and a quarter inches in front 

 of the anus — and, opening the left ischio-rectal fossa, ends at the junction of the 

 outer and middle thirds of a line drawn between the posterior margin of the anus 

 and the ischial tuberosity. This incision should be deepest near its upper end — not 

 far, at its upper and deepest portion, from the apex of the " perineal triangle" — and 

 should become shallower as it passes into the ischio-rectal space. It divides skin, 



Fig. i6",o. 



I f 



Corpus cav- /^ 



prnrtciitn nit ^ 



ernosum, cut 

 Adductor brevis 



Adductor 

 maguus 



Ramus of 

 ischium 

 Tuber ischii 



Obturator 



internus 



Levator ani 



Greater sacro- 

 sciatic ligament 



Coccygeus 



Gluteus 

 maximus, cut 



Sectional surface of 

 corpus spongiosum 





Corpus cavemosum, 



cut 

 Urethra 



Subpubic ligament 



-Prostate 



-Tuber ischii 



- Obturator 



internus 



- Greater sacro- 

 sciatic ligament 



-dluteus 

 maximus 



 Coccyx 



-.''"-iSt 



Deep dissection of perineum, in which root of penis has been removed, showing urethra 

 emerging from prostate, which is partly exposed between levalores ani. 



both layers of superficial fascia, the superficial transverse perineal muscle, artery, and 

 nerve, the lower edge of the superficial layer of the triangular ligament, and, as it 

 crosses the ischio-rectal fossa, the inferior hemorrhoidal vessels and nerves. 



The left forefinger of the operator now guides the knife into the groove of the 

 staf^, and the incision is deepened with the knife-blade inclined laterally and pushed 

 onward into the bladder, dividing the compressor urethrae muscle, the membranous 

 urethra, the superior layer of the triangular ligament, a few median fibres of the leva- 

 tor ani, the prostatic urethra, and a portion of the left lobe of the prostate. 



The neck of the bladder should be dilated with the finger rather than incised, 

 and will, without serious laceration, permit the extraction of a stone of the diameter 

 of an inch to an inch and a quarter. 



In children the following facts should be borne in mind : (a) the relative nar- 

 rowness of the pelvis, limiting the operative space ; (d) the undeveloped condition 



