Page 158 - Clinical Anatomy

ECA2 7/18/06 6:43 PM Page 143

The female genital organs 143

3◊◊The cervix drains in three directions—laterally, in the broad ligament, to
the external iliac nodes; posterolaterally along the uterine vessels to the
internal iliac nodes; and posteriorly along the recto-uterine folds to the
sacral nodes.
Always examine the inguinal nodes in a suspected carcinoma of the
corpus uteri— they may be involved by lymphatic spread along the round
ligament.

Structure
The body of the uterus is covered with peritoneum except where this is
reflected off at two sites, anteriorly on to the bladder at the uterine isthmus
and laterally at the broad ligaments. Anteriorly, the peritoneum is only
loosely adherent to the supravaginal cervix; this allows for bladder disten-
sion. The muscle wall is thick and made up of a criss-cross of involuntary
fibres mixed with fibroelastic connective tissue.
The mucosa is applied directly to muscle with no submucosa inter-
vening. The mucosa of the body of the uterus is the endometrium, made
up of a single layer of cuboidal ciliated cells forming simple tubular
glands which dip down to the underlying muscular wall. Below this
epithelium is a stroma of connective tissue containing blood vessels and
round cells.
The cervical canal epithelium is made up of tall columnar cells which
form a series of complicated branching glands; these secrete an alkaline
mucus which forms a protective ‘cervical plug’ filling the canal.
The vaginal aspect of the cervix is covered with a stratified squamous
epithelium continuous with that of the vagina.
The mucosa of the corpus undergoes extensive changes during the
menstrual cycle which may be briefly summarized thus:
1◊◊first 4 days—desquamation of its superficial two-thirds with bleeding;
2◊◊subsequent 2–3 days — rapid reconstitution of the raw mucosal
surface by growth from the remaining epithelial cells in the depths of the
glands;
3◊◊by the 14th day the endometrium has reformed; this is the end of the pro-
liferative phase;
4◊◊from the 14th day until the menstrual flow commences is the secretory
phase; the endometrium thickens, the glands lengthen and distend with
fluid and the stroma becomes oedematous and stuffed with white cells.
At the end of this phase three layers can be defined:
1◊◊a compact superficial zone;
2◊◊a spongy middle zone—with dilated glands and oedematous stroma;
3◊◊a basal zone of inactive non-secreting tubules.
With degeneration of the corpus luteum there is shrinkage of the
endometrium, the arteries retract and coil, producing ischaemia of the
middle and superficial zones, which then desquamate. It is probable that
spasm of the vessels in the basal layer (which remains non-desquamated)
prevents the woman bleeding to death.
Only very slight desquamation and bleeding takes place in the mucosa
of the cervical canal.