INTERNAL GENITAL ORGANS

The internal genital organs in female include-

-Vagina

-Uterus

-Fallopian tubes 

-The ovaries

Vagina-The vagina is a fibromusculomembranous sheath communicating the uterine cavity with the exterior at the vulva.The canal is directed upwards and backwards forming an angle of 45° with the horizontal in erect posture. The long axis of the vagina almost lies parallel to the plane of the pelvic inlet and at right angles to that of the uterus. The diameter of the canal is about 2.5 cm, being widest in the upper part and narrowest at its introitus.

Relations- 

Anterior—The upper one-third is related with base of the bladder and the lower two-thirds are with the urethra, the lower half of which is firmly embedded with its wall.

Posterior—The upper one-third is related with the pouch of Douglas, the middle-third with the anterior rectal wall separated by rectovaginal septum and the lower-third is separated from the anal canal by the perineal body

Lateral walls—The upper one-third is related with the pelvic cellular tissue at the base of broad ligament in which the ureter and the uterine artery lie approximately 2 cm from the lateral fornices. The middle third is blended with the levator ani and the lower-third is related with the bulbocavernosus muscles, vestibular bulbs and Bartholin’s glands.

Structure-

 Mucous coat- which is lined by stratified squamous epithelium without any secreting glands

Submucous layer- of loose areolar vascular tissues

Muscular layer -consisting of indistinct inner circular and outer longitudinal muscles and

 Fibrous coat- derived from the endopelvic fascia and is highly vascular. 

PH  (Vaginal secration)-

The vaginal pH, from puberty to menopause, is acidic because of the presence of Döderlein’s bacilli which produce lactic acid from the glycogen present in the exfoliated cells. The pH varies with the estrogenic activity and ranges between 4 and 5. 

Blood supply-—

 -Cervicovaginal branch of the uterine artery

- Vaginal artery—a branch of anterior division of internal iliac or in common origin with the uterine,

- Middle rectal

- internal pudendal. 

Veins -

- Internal iliac veins

-Internal pudendal veins. 

Lymphatics-

- Upper one-third—internal iliac group

 -Middle one-third up to hymen—internal iliac group,

-Below the hymen—superficial inguinal group.

Nerve supply-

-The vagina is supplied by sympathetic and parasympathetic from the pelvic plexus.

-The lower part is supplied by the pudendal nerve. 

The Uterus-

The uterus is a hollow pyriform muscular organ situated in the pelvis between the bladder in front and the rectum behind. 

Measurements and Parts-

 About 8 cm long, 5 cm wide at the fundus and its walls are about 1.25 cm thick. Its weight varies from 50 gm to 80 gm.It consist of following parts- 

-Body or corpus 

-Isthmus  

- Cervix 

Body or corpus  - 

The body is further divided into fundus—the part which lies above the openings of the uterine tubes. The body proper is triangular and lies between the openings of the tubes and the isthmus. The superolateral angles of the body of the uterus project outwards from the junction of the fundus and body and is called the cornua of the uterus. The uterine tube, round ligament and ligament of the ovary are attached to it. 

 Isthmus-

Isthmus is a constricted part measuring about 0.5 cm, situated between the body and the cervix. It is limited above by the anatomical internal os and below by the histological internal os (Aschoff). 

 Cervix-

Cervix is cylindrical in shape and measures about 2.5 cm. It extends from the isthmus and ends at the external os which opens into the vagina after perforating its anterior wall.

Relation-

Anteriorly-

Above the internal os, the body forms the posterior wall of the utero vesical pouch. Below the internal os, it is separated from the base of the bladder by loose areolar tissue.

Posteriorly—It is covered with peritoneum and forms the anterior wall of the pouch of Douglas containing coils of intestine.

Laterally—The double fold of peritoneum of the broad ligament are attached between which the uterine artery ascends up. Attachment of the Mackenrodt’s ligament extends from the internal os down to the supravaginal cervix and lateral vaginal wall. 

Structures-

Body — The wall consists of three layers from outside inwards

Parametrium- It is the serous coat which invests the entire organ except on the lateral borders. The peritoneum is intimately adherent to the underlying muscles.

 Myometrium- It consists of thick bundles of smooth muscle fibers held by connective tissues and are arranged in various directions. 

Endometrium- The mucous lining of the cavity is called endometrium. As there is no submucous layer, the endometrium is directly opposed to the muscle coat. It consists of lamina propria and surface epithelium.

Blood supply-

Arteial supply- The blood supply is from the uterine arteries one on each side.

Veins- The venous channels correspond to the arterial course and drain into internal iliac veins.

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