UTERUS AND ITS APPENDAGES. 



706 



The round ligament is composed of smooth 

 muscular fibre, derived from the uterus, and 

 arranged in bundles, surrounded by connective 

 tissue, of striated muscle, continuous with that 

 of the abdominal parietes, and of blood-ves- 

 sels, lymphatics and nerves. 



The peritoneal covering of the round liga- 

 ment is occasionally prolonged in young sub- 

 jects at its lower part through a portion of the 

 inguinal canal, where it forms the canal of Nuck. 

 This is usually obliterated in adults, where the 

 arrangement of the tendinous part of the round 

 ligament just described serves to close the in- 

 ternal ring, and to prevent, in a great measure, 

 the occurrence of inguinal hernia in the female. 

 The persistence of this canal probably leads 

 to the abnormal descent of the ovary into the 

 labium, constituting hernia of the ovary (see 

 p. 574.); an occurrence exactly comparable 

 with the normal descent of the testis into the 

 scrotum of the male. 



VAGINA. 

 NORMAL ANATOMY. 



Syn. Vuho-uterine canal. The vagina con- 

 stitutes a flattened cylindroid, extending from 

 the vulvar orifice to the neck of the uterus. 

 It lies entirely within the pelvis, between 

 the bladder and rectum, running very nearly 

 in the direction of the axis of the pelvic outlet, 

 but having a slight curvature forwards. The 

 orifice of the vagina is bounded anteriorly 

 by the vestibule, laterally by the nymphae, and 

 posteriorly by the hymen. The upper or blind 

 extremity, termed the fornix, receives the va- 

 ginal portion of the uterine neck, which is not 

 placed exactly at the termination of the canal, 

 but appears as if it were let into its upper 

 wall (fig. 433.). 



Dimensions. The vagina is capable of con- 

 siderable extension. It varies in dimensions 

 in different subjects. In the ordinary virgin 

 state, the anterior wall, which is the shorter, 

 measures, from the median tubercle of the 

 vagina to the anterior lip of the uterus, less 

 than two and a half inches ; and the posterior 

 wall, from the centre of the vulvar orifice to 

 the end of the fornix, three inches. The 

 transverse diameter, in the natural state of the 

 canal, which is flattened from before back- 

 wards, so that the anterior and posterior walls 

 are in contact, measures ordinarily one inch 

 and a quarter. But when the canal is dis- 

 tended, and after the birth of many children, 

 these dimensions may be much exceeded. 



External surface. The following are the 

 relations of the external surface of the vagina. 

 Anteriorly, it is connected to the urethra and 

 base of the bladder by areolar tissue. Laterally, 

 it is in relation with the root of the broad liga- 

 ment and the pelvic fascia. Posteriorly, in the 

 first part of its course, it is covered by the pe- 

 ritoneum, forming the anterior wall of the 

 retro-uterine pouch, or space of Douglas ; 

 secondly, where the peritoneum ceases, and 

 for about half its course, it is united to the 

 rectum ; and lastly, it is separated from the 

 latter by the thickness of the perineum. 



Composition. The walls of the vagina are 

 of variable thickness in different parts, the 

 average being \'". They are composed of 

 three coats. The outermost of these is formed 

 of fibrous tissue, intermixed with an abundance 

 of elastic fibre. Beneath this is a second or 

 muscular coat, containing unstriped muscular 

 fibre and fibre-cells, which, during pregnancy, 

 undergo a development similar to that of the 

 uterine fibre. The third, or innermost, is the 

 mucous coat, composed of a dense connective 

 tissue, with much admixture of elastic fibre, 

 to which is due a great part of that elasticity 

 and distensibility with which the vagina is en- 

 dowed. Imbedded in the substance of the 

 mucous membrane, which is covered by squa- 

 mous epithelium, are numerous rnuciparous 

 follicles. 



Internal surface. Upon the inner surface 

 of the canal the mucous membrane is thrown 

 into folds, which, in the virgin, form numerous 

 closely-set transverse rugae, that are arranged 

 with a certain approach to regularity, and 

 sometimes exhibit a central connecting line or 

 raphe, forming the columnce rugarum, upon 

 the anterior and posterior walls. At the sides 

 of the vagina these folds are less prominent, 

 and take an oblique or longitudinal direction. 

 In some subjects the rugae are covered by, or 

 are chiefly composed of, short, crowded ver- 

 rucose papillae, intermixed with others more 

 filiform. They become larger towards the 

 vaginal orifice, where they sometimes take the 

 form of little leaflets, resembling the smaller 

 fimbriae of the Fallopian tube, especially about 

 the meatus urinarius. After numerous acts of 

 parturition, as well as from frequent inter- 

 course, the folds become obliterated, and the 

 inner surface of the vagina is rendered nearly 

 or entirely smooth. 



Arteries. A special artery usually exists for 

 the vagina, which may arise either from the 

 hypogastric, internal pudic, middle haemor- 

 rhoidal, or even from the obturator. From one 

 of these origins the artery descends along each 

 side of the vagina, giving off in its course 

 numerous branches, which inosculate in the 

 recto-vaginal septum with those of the op- 

 posite side. Near its extremity, the artery 

 sends off a considerable branch to the bulb of 

 the vagina, and after supplying the external 

 organs, it terminates by inosculating with the 

 artery of the opposite side, between the vagina 

 and rectum. One or two separate branches 

 are generally found to arise from the uterine 

 artery. These descend between the bladder 

 and the vagina, supplying branches to both 

 those parts. An abundant and intricate net- 

 work is formed in the vaginal walls by the 

 ramifications of the smaller vessels derived 

 from these sources, which interpenetrate the 

 several coats down to the mucous membrane. 

 Veins. The veins which collect the blood 

 from the labia, constrictor muscles, and mu- 

 cous membrane of the vagina, and from the 

 erectile tissue forming the vaginal bulb, unite 

 to form a considerable plexus, especially 

 around the vulvar orifice termed the vaginal 

 plexus. From this plexus branches pass to 



