ABDOMEN AND PELVIS 519 



DISSECTION OF THE MALE PELVIS. 



Before beginning the dissection of the pelvic viscera, review 

 the anatomy of the bones entering into the formation of the 

 pelvis. Compare the male and female pelves, noting the differ- 

 ences in the diameters, angles of inclination, size and general 

 structure of the bones. Before disturbing any relations examine 

 the position of each viscus. Compare the positions found in 

 the adult with tho*se in the child. Note the peritoneal relations 

 of each viscus and study the peritoneal folds. 



Peritoneal Folds. (Vide Spalteholz, Fig. 667.) 



(a) Transverse vesical fold (plica vesicalis transversa). 



This fold disappears when the bladder is distended. 



(b) Pubovesical fold (plica pubovesicalis) . 



(c) Rectovesical fold (plica rectovesicalis). 



The rectovesical folds are raised by the obliterated umbilical 

 arteries. They form the lateral boundaries of a deep excavation 

 between the bladder and the rectum (excavatio rectovesicalis). In 

 the folds will be found the rectovesical muscles (Mm. rectovesi- 

 cales), which are composed of smooth muscle-fibres derived from 

 the walls of the neighboring viscera. 



(d) Mesorectum. A fold of peritoneum connecting the first part of the 



rectum to the posterior wall of the pelvis. 



Hypogastric Plexus (Plexus hypogastricus). (Vide Toldt, Figs. 1331 

 and 1333.) 



This sympathetic plexus rests upon the body of the fifth 

 lumbar vertebra between the common iliac arteries. Establish 

 its relation to the plexus aorticus and the ganglia lumbalia. In- 

 feriorly it divides into two parts, which accompany the hypo- 

 gastric arteries into the pelvis. Dissect out the plexus, trace it 

 downward into the pelvis, and dissect out the following plexuses 

 and nerves derived from it : 



(a) Middle hemorrhoidal plexus (plexus haemorrhoidalis medius). 



(b) Prostatic plexus (plexus prostaticus) . 



(c) Deferential plexus (plexus deferentialis). 



(d) Vesical plexus (plexus vesicalis). 



(da) Superior vesical nerves (Nn. vesicales superiores). 



(db) Inferior vesical nerves (Nn. vesicales inferiores). 



(e) Cavernous plexus of penis (plexus cavernosus penis). 



(ea) Greater cavernous nerve of penis (N. cavernosus penis 



major). 



(eb) Lesser cavernous nerves of penis (Nn. cavernosi penis 



minores). 



