Beckmann obstetrics and gynecology pdf

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Een lijst met recente wijzigingen in deze wiki. Deze pagina is voor het laatst bewerkt op 20 dec 2017 om 22:32. This is a good article. Follow the link for more information. Midwives and doctors use the extent of the dilation of the cervix to assist decision-making during childbirth. HPV vaccines, developed in the early 21st century, reduce the risk of cervical cancer by preventing infections from the main cancer-causing strains of HPV.

Diagram of the uterus and part of the vagina. The cervix is more tightly connected to surrounding structures than the rest of the uterus. It is wider in the middle and narrower at each end. The anterior and posterior walls of the canal each have a vertical fold, from which ridges run diagonally upwards and laterally. The anterior and posterior ridges are arranged in such a way that they interlock with each other and close the canal. They are often effaced after pregnancy. In women who have not had a vaginal delivery, the external opening is small and circular, and in women who have had a vaginal delivery, it is slit-like.

However, there are variations as lymphatic drainage from the cervix travels to different sets of pelvic nodes in some people. This has implications in scanning nodes for involvement in cervical cancer. During most of the menstrual cycle, the cervix remains firm, and is positioned low and closed. The point at which these two original epithelia meet is called the original squamocolumnar junction. New studies show, however, that all the cervical as well as large part of the vaginal epithelium are derived from Müllerian duct tissue and that phenotypic differences might be due to other causes. The squamocolumnar junction of the cervix: The ectocervix, with its stratified squamous epithelium, is visible on the left. Simple columnar epithelium, typical of the endocervix, is visible on the right.

The junction between these two types of epithelia is called the squamocolumnar junction. The mucosa of the endocervix is not shed during menstruation. Upon entering puberty, due to hormonal influence, and during pregnancy, the columnar epithelium extends outwards over the ectocervix as the cervix everts. Hence, this also causes the squamocolumnar junction to move outwards onto the vaginal portion of the cervix, where it is exposed to the acidic vaginal environment. The new squamocolumnar junction is therefore internal to the original squamocolumnar junction, and the zone of unstable epithelium between the two junctions is called the transformation zone of the cervix. After menopause, the uterine structures involute and the functional squamocolumnar junction moves into the cervical canal.

Both gland openings and Nabothian cysts are helpful to identify the transformation zone. Some sperm remains in cervical crypts, infoldings of the endocervix, which act as a reservoir, releasing sperm over several hours and maximising the chances of fertilisation. Although the “upsuck theory” has been generally accepted for some years, it has been disputed due to lack of evidence, small sample size, and methodological errors. 600 mg around the time of ovulation. These changes allow it to function either as a barrier or a transport medium to spermatozoa.