![]() ![]() ![]() Also, the cervix of a parous woman tends to have slightly less sensory appreciation, which may be due to damage to nerve endings during childbirth. Hence, procedures such as biopsy, thermal coagulation, and cryotherapy are relatively well tolerated in most women, although there is good evidence that local anaesthesia effectively prevents the discomfort of these procedures. The endocervix has extensive sensory nerve endings, whereas there are very few in the ectocervix. The nerve supply to the cervix is derived from the hypogastric plexus. The lymphatic vessels from the cervix drain into the common iliac, external iliac, internal iliac, obturator, and parametrial nodes. The veins of the cervix run parallel to the arteries and drain into the hypogastric venous plexus. The cervical branches of the uterine arteries descend in the lateral aspects of the cervix at the 3 o’clock and 9 o’clock positions. The arterial supply of the cervix is derived from the internal iliac arteries through the cervical and vaginal branches of the uterine arteries. The stroma of the cervix is composed of dense, fibromuscular tissue through which vascular, lymphatic, and nerve supplies to the cervix pass and form a complex plexus. ![]() Glandular cervical cancer originates in either the TZ or the glandular epithelium above the TZ. Squamous cervical cancer accounts for the majority of cervical cancer and originates in the TZ. These are the lateral, anterior, and posterior fornices and are where the vaginal epithelium sweeps into the cervix circumferentially. The lower half, or intravaginal part, of the cervix lies at the top of the vagina, surrounded by the vaginal fornices. At the upper end of the cervical canal, the endocervical epithelium becomes the endometrial lining of the uterine cavity. The endocervical or glandular epithelium is not usually visible to the naked eye at speculum examination. The visible external lining of the cervix derives from the vaginal (squamous) epithelium. The external os of the cervix will nearly always be visible to the naked eye at speculum examination. When the speculum is positioned properly and opened, the cervix tends to become positioned centrally and in a plane perpendicular to the longitudinal axis of the vagina. When the uterus is retroverted, the cervix tends to enter the vagina slightly more anteriorly, and in this case the cervix may be more difficult to locate at first speculum exposure. When the speculum is opened, the cervix tends to be brought more centrally into view and into line with the longitudinal axis of the vagina. When the uterus is anteverted, the cervix enters the vaginal vault through a slightly posterior approach, whereby at speculum examination the cervical os is directed towards the posterior vaginal wall ( Fig. 2.1). It may be small or large and usually becomes more ectocervical during a woman’s reproductive years, returning to an endocervical position after menopause. The epithelium between these two SCJs is the TZ or transition zone, and its position is also variable. In colposcopy terminology, the SCJ is this new SCJ. The original SCJ originates in the endocervical canal, but as the cervix everts during these times, the SCJ comes to lie on the ectocervix and becomes the new SCJ. The SCJ is dynamic and moves during early adolescence and during a first pregnancy. ![]() The squamous epithelium meets the glandular epithelium at the squamocolumnar junction (SCJ). The endocervical canal is lined with glandular epithelium, and the ectocervix is lined with squamous epithelium. The cervix has several different linings. In this drawing, the uterus is anteverted. Line drawing of normal female genital tract anatomy: sagittal section. ![]()
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