ABDOMEN AND PELVIS 449 



Nerves. 



(a) Dorsal nerve of clitoris (N. dorsalis clitoridis). 



Determine the exact course of this nerve. What relation does 

 it bear to the dorsal artery of the clitoris and to the dorsal vein ? 

 What relation does the latter vein bear to the ligamentum arcua- 

 tum pubis and the ligamentum transversum pelvis? Demonstrate 

 the presence of a part of the glandulae vestibulares majores in 

 the " middle compartment of the perineum." 

 Urethra. 



Note the general direction and extent of the urethra in the female. 

 What is its relation to the anterior vaginal wall? (Vide Figs. 231, 291, 

 and 293.) 



The superior boundary of the diaphragma urogenitale is 

 formed by the superior fascia of the urogenital diaphragm 

 (fascia diapliragmatis urogenitalis superior) (O. T. deep or 

 posterior layer of triangular ligament). 



Note that these (the superior and inferior) layers fuse pos- 

 teriorly and become continuous with the deep layer of the super- 

 ficial fascia of the perineum, or " Colles' fascia." Anteriorly 

 they a] so fuse to form the transverse ligament of the pelvis 

 (ligamentum transversum pelvis). The dorsal vein of the cli- 

 toris separates the latter from a ligament just below the pubis, 

 which is known as the arcuate ligament of the pubis (ligamentum 

 arcuatum pubis). 



ANAL REGION (REGIO ANALIS) AND DIAPHRAGM 



OF PELVIS (DIAPHRAGMA PELVIS) IN 



BOTH SEXES. 



Review at this stage of the dissection the general character- 

 istics and disposition of the fascia in this region. After having 

 reviewed this, remove it by blunt dissection. 



External Sphincter Muscle of Anus (M. sphincter ani externus). 

 (Figs. 222-224, 2 3! 2 73 28 9-) 



Clean this muscle, noting carefully its form, position, origin, 

 insertion, action, and innervation, and dissect out the following 

 layers, proceeding from without inward : 



(a) External layer ("superficial sphincter" of Cruveilhier, the "skin 

 muscle" of Luschka). It is inserted into the skin about the anus. 



(&) Anococcygeal layer, formed by the fibres arising from the coccyx 

 and the ligamentum anococcygeum, encircling the anus and inserted 

 29 



