1042 THE FEMALE REPRODUCTIVE ORGANS 



part of the male canal, and is similarly related to tlie su])erior and inferior triangular 

 ligaments. It is about an ineli and" a half (37 nun.) in length, and is directed 

 ui)\vards and slightly l)ackwards to open into the bladder about an inch (25 

 mm.) behind the niiddle of the symi)hysis. Its posterior wall is in contact with 

 the vagina, and it is surrounded in front and at the sides by a plexus of veins 

 (plexus of Santorini). The posterior margin of the meatus usually i)resents a 

 tuliercular i)rominence by which the position of the orifice may be distinguished 

 during catheterism. 



As in the male urethra, the narrowest portion of the canal is the external meatus, 

 but the whole tul)e is sutliciently dilatable in most cases to allow the careful intro- 

 duction of the linger while the patient is under an anaesthetic. A case is recorded 

 ])V William Cowper (1697) in which, as a result of an imperforate condition of the 

 hymen, it l)ecame the channel of sexual congress. 



Structurally it consists of a highly elastic mucous membrane and a strong mus- 

 cular coat. The mucosa is lined with three or four layers of ei)ithelial cells, the 

 more superficial of which are prismatic in form, and presents a few lacunar and 

 some rudimentary glandular follicles. The muscular coat is divisible into external 

 circular and internal longitudinal layers, both intermingled with fibres of elastic 

 tissue and with large venous plexuses which may undergo varicose dilatation near 

 the external orifice and form a pile-like tumour. The circular fibres are very 

 strongly develoj^ed at the vesical end of the canal and constitute a powerful 

 sphincter; these are surrounded by a quantity of striped and unstriped fibres which 

 form an incomj)lete ring, deficient only in its posterior or vaginal segment, and 

 proba])ly represent the prostatic fibres and the deep transversus perinaei of the male. 

 It is surrounded by a muscular sphincter composed of striped and unstriped fibre 

 corresponding to the deep transversus perina?! in the male, and partly, perhaps, to 

 the musculature of the prostate. 



THE VAGINA 



The vagina is a passage which extends upwards and slightly backwards from 

 its external opening at the vestibule, and terminates above by embracing the neck 

 of the uterus. Its vulvar aperture is guarded in the virgin b}^ a fold of mucous 

 memljrane called the hymen. 



Form and direction (figs. 633, 634). — In its ordinary condition the vaginal 

 canal is represented by a fissure which in horizontal section assumes the form of 

 the letter H, with a transverse limb about an inch in length and two short verti- 

 cal limbs (fig. 633). In longitudinal section (fig. 633) the fissure branches above, 

 a short limb (occasionally ill-marked or absent) passing in front of the anterior lip 

 of the OS uteri, a much longer limb extending behind the os to end about three- 

 quarters of an inch above the extremity of the posterior lip. The angle of reflexion 

 of the vaginal on to the uterine mucous membrane is called the fornix. The 

 direction of the passage is upwards and backwards, forming an angle of about 30° 

 with the long axis of the body, and usually presenting a slight posterior concavity 

 adapted to the convexity of the rectal ampulla; the course and direction, however, 

 vary with the degree of pelvic inclination peculiar to the individual, and to some 

 extent with the condition of the bladder and rectum. 



The two walls are of very une(iual length, the anterior measuring al)out two 

 inches and three-fjuarters (7 cm.), while the posterior is prolonged ui)wards nearly 

 an inch (9..") cm. ) furtbci-. 



Relations. — Anteriorly, it is o])posed to the urethra and posterior wall of the 

 bladder. It is intimately united with the lower two-thirds of the urethra, but is 

 separated from the u})per third and from the bladder by loose connective tissue 

 continuous with the sul)peritoneal fascia. The canal as a whole is narrowest below, 

 and gradually increases as it ascends, reaching its greatest admeasurement where it 

 surrounds the os uteri. Its dilatability is enormous, as may be inferred from the 

 passage of the foetus in parturition. The ureters pierce the Vesical wall in fi-ont of 

 the vagina an inch and a (piarter below the level of the os uteri. Posteriorly, it 

 is in relation with the rectum, but is separated from it above for about three- 



