Vaginal Structure

A stratified squamous epithelium lines the vagina and the vaginal cervix; it contains no glands and is lubricated partly by cervical mucus and partly by desquamated vaginal epithelial cells. In nulliparous women the vaginal wall is rugose, but it becomes smoother after childbirth. The rugae of the

Fig. 102 Coronal section of the uterus and vagina. Note the important relationships of ureter and uterine artery.

Fig. 102 Coronal section of the uterus and vagina. Note the important relationships of ureter and uterine artery.

Vagina Rugous

anterior wall are situated transversely; this allows for filling of the bladder and for intercourse. In contrast, the rugae on the posterior wall run longitudinally. This allows for sideways stretching to accommodate a rectum distended with stool and for the passage of the fetal head.

Beneath the epithelial coat is a thin connective tissue layer separating it from the muscular wall which is made up of a criss-cross arrangement of involuntary muscle fibres. This muscle layer is ensheathed in a fascial capsule which blends with adjacent pelvic connective tissues, so that the vagina is firmly supported in place.

In old age the vagina shrinks in length and diameter. The cervix projects far less into it so that the fornices all but disappear.

The uterus (Figs 101, 102)

The uterus is a pear-shaped organ, 3 in (7.5 cm) in length, made up of the fundus, body and cervix. The Fallopian (uterine) tubes enter into each superolateral angle (the cornu) above which lies the fundus.

The body of the uterus narrows to a waist termed the isthmus, continuing into the cervix which is embraced about its middle by the vagina; this attachment delimits a supravaginal and vaginal part of the cervix.

The isthmus is 1.5 mm wide. The anatomical internal os marks its junction with the uterine body but its mucosa is histologically similar to the endometrium. The isthmus is that part of the uterus which becomes the lower segment in pregnancy.

The cavity of the uterine body is triangular in coronal section, but in the sagittal plane it is no more than a slit. This cavity communicates via the internal os with the cervical canal which, in turn, opens into the vagina by the external os.

The nulliparous external os is circular but after childbirth it becomes a transverse slit with an anterior and a posterior lip.

The non-pregnant cervix has the firm consistency of the nose; the pregnant cervix has the soft consistency of the lips.

In fetal life the cervix is considerably larger than the body; in childhood (the infantile uterus) the cervix is still twice the size of the body but, during puberty, the uterus enlarges to its adult size and proportions by relative overgrowth of the body. The adult uterus is bent forward on itself at about the level of the internal os to form an angle of 170°; this is termed anteflexion of the uterus. Moreover, the axis of the cervix forms an angle of 90° with the axis of the vagina—anteversion of the uterus. The uterus thus lies in an almost horizontal plane.

In retroversion of the uterus, the axis of the cervix is directed upwards and backwards. Normally on vaginal examination the lowermost part of the cervix to be felt is its anterior lip; in retroversion either the os or the posterior lip becomes the presenting part.

In retroflexion the axis of the body of the uterus passes upwards and backwards in relation to the axis of the cervix.

Frequently these two conditions co-exist. They may be mobile and symptomless—as a result of distension of the bladder or purely as a development anomaly. Indeed, mobile retroversion is found in a quarter of the female population and may be regarded as a normal variant. Less commonly, they are fixed, the result of adhesions, previous pelvic infection, endometriosis or the pressure of a tumour in front of the uterus (Fig. 103).

Pregnancy Diet Plan

Pregnancy Diet Plan

The first trimester is very important for the mother and the baby. For most women it is common to find out about their pregnancy after they have missed their menstrual cycle. Since, not all women note their menstrual cycle and dates of intercourse, it may cause slight confusion about the exact date of conception. That is why most women find out that they are pregnant only after one month of pregnancy.

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Responses

  • Arthur
    Where is the vagina situated?
    6 years ago
  • sadoc
    Which is the anterior wall of the vagina>?
    5 years ago
  • alfreda baresi
    What is the imoprotece os a vagina?
    3 years ago
  • aleisha
    What are the structure of vagina?
    1 year ago
  • Alvin Hall
    Which part is vagina wall?
    8 months ago
  • stacey carlson
    What is the consistency of cervical transverse slit?
    2 months ago
  • jemima oldbuck
    Where is vaginal epithelium oriented in the vagina (drawing)?
    1 month ago
  • aloisia
    What is os in uterine structure?
    22 days ago

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