FEMALE PELVIS VAGINA. 545 



Fig. 241 * 





and its speedy return to its original diameter. The meatus is encircled 

 by a ring of fibrous tissue, which prevents it from distending with the 

 same facility as the rest of the canal ; hence it is sometimes advantageous 

 in performing this operation to divide the margin of the meatus slightly 

 with the knife. 



VAGINA. 



The Vagina is a membranous canal, leading from the vulva to the 

 uterus, and corresponding in direction with the axis of the outlet of the 

 pelvis. It is constricted at its commencement, but near the uterus becomes 

 dilated ; and is closed by the contact of the anterior with the posterior 

 wall. Its length is variable ; but it is always longer upon the posterior 

 than upon the anterior wall, the former being usually about five or six 

 inches in length, and the latter four or five. It is attached to the cervix 

 of the uterus, which latter projects into the upper extremity of the canal, 



In Structure the vagina is composed of a mucous lining, a layer of 

 erectile tissue, and an external tunic of contractile fibrous tissue, resembling 

 the dartos of the scrotum. The upper fourth of the posterior wall of the 



* A side view of the viscera of the female pelvis. 1. The symphysis pubi&; to the 

 upper part of which the tendon of the rectus muscle is attached. 2. The abdominal 

 parietes. 3. The collection of fat, forming the prominence of the mons Veneris. 4. The 

 urinary bladder. 5. The entrance of the left ureter. 6. The canal of the urethra, con- 

 verted into a mere fissure by the contraction of its walls. 7. The meatus urinarius. 

 8. The clitoris, with its praeputiurn, divided through the middle. 9. The left nympha. 

 10. The left labium majus. 11. The meatus of the vagina, narrowed by the contraction 

 of its sphincter. 12. 22. The canal of the vagina, upon which the transverse rugae are 

 Apparent. 13. The thick wall of separation between the base of the bladder and the 

 vagina. 14. The wall of separation between the vagina and rectum. 15. The perineum, 

 16. The os uteri. 17. Its cervix. 18. The fundus uteri. The cavitas uteri is seen along 

 the centre of the organ. 19. The rectum, showing the disposition of its mucous mem- 

 brane. 20. The anus. 21. The upper part of the rectum, invested by the peritoneum. 

 23. The utero-vesical fold of peritoneum. The recto-uterine fold is seen between the 

 rectum and the posterior wall of the vagina. 24. The reflexion of the peritoneum, from 

 the apex of the bladder upon the urachus to the internal surface of the abdominal p>. 

 rietes. 25. The last lumbar vertebra. 26. The sacrum. 27. The coccyx. 



46* 2K 



