THE LABIA AND THE VESTIBULE. 



2023 



2 cm. behind the clitoris and breaks the smooth mucous surface of the vestibular roof. 

 The opening of the urethra is very variable in form, being crescentic, stellate, crucial 

 or linear, a sagittal cleft of about 5 mm. being the most usual type. Close to the 

 urethral orifice, at the sides or somewhat behind, lie the minute depressions marking 

 the openings of the paraurethral ducts (page 1924). In young subjects, a pair of 

 fine sagittal folds can often be traced over the roof of the vestibule from the urethral 

 papilla to the frenum of the clitoris. 



The area between the orifice of the urethra and that of the vagina is subject to 

 considerable individual variation in size and detail owing to differences in the extent 

 to which the lower end of the anterior vaginal column (carina urethralis) encroaches 

 upon the vestibule. After rupture of the hymen has occurred, the vaginal entrance 

 is surrounded by a series of irregular fimbriated projections that form the carunculce 

 hymenales which, after labor, become reduced to inconspicuous nodules. Included 

 between the posterior margin of the hymen and the backwardly directed arching fold 

 of the fourchette is the fossa navicularis, a shallow, crescentic, pocket-like depres- 



FIG. 1707. 



Central fat-body 



Labi urn majus 



Labium minus 



Inner surface 



Sebaceous glands on external 

 cutaneous surfaces 



Interlabial groove 



Section across the labia of very young child. X 18. 



sion. This recess is best marked in the virgin, when the nymphae are well developed, 

 and is usually effaced after child-bearing. 



Vessels. The arteries supplying the labia majora are chiefly the anterior and 

 posterior labial branches from the external and internal pudics respectively. A 

 small twig from the superficial external pudic is distributed in the vicinity of the 

 anterior commissure ; several others from the deep external pudic end in the anterior 

 half of the labium, while the posterior half is supplied by the posterior labial twigs 

 from the superficial perineal branch from the internal pudic artery. Additional 

 small twigs from the anterior terminal branch of the obturator artery are distributed 

 to the outer surface of the labia. The nymphse also receive their blood from the 

 anterior and posterior labial arteries through small branches that enter the front and 

 hind parts of the folds and assist in nourishing the mucous membrane lining the roof 

 of the vestibule. The arteries from these various sources freely anastomose with one 

 another as well as with adjacent vessels. While the veins of the labia majora in 

 general follow the corresponding arteries, they communicate with neighboring 

 systems, particularly with the inferior hemorrhoidal and the pelvic plexuses. The 

 veins of the nymphae, unusually numerous and large, present a plexiform arrangement, 

 whereby the labia acquire the character of erectile structures. The collecting stems 



