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Date posted: November 27, 2011

Dr. Meera Narendran BHMS,MD(Hom)

The uterus is a hollow, thick walled muscular organs – lies in the lesser pelvis normally with its body lying on top of urinary bladder and its neck between the urinary bladder and rectum.

It is about 3 inches (7.5cm) long and 2 inches (5cm) broad and one inch (2.5cm) thick. It weighs about go gms.
Normally the long axis of the uterus forms as angle of 90 degrees with the long axis of the vagina – This forward bending of uterus relative to the Vagina is called anteversion. The uterine body is slightly bend anteriorly relative to the cervix, this is called anteflexion. The angle of anteflexion is about 120 degrees. The position of the uterus changes with the degree of fullness of the bladder and rectum. During pregnancy uterus enlarges greatly to accommodate the fetus.

Parts of uterus
The uterus is divisible into 2 main parts.
1) The body
2) The cervix

1. Body
Forms the upper two-thirds. It has 2 parts.
Fundus
The rounded part of the body that lies superior to the orifices of the uterine tubes.
Isthmus
The relatively constricted region of the body (one cm. long) just above the cervix.
The body of the uterus lies between the layers of the broad ligament and is freely movable. It has 2 surfaces.
Vesical (related to the bladder) and  intestinal.
The uterine horns are superolateral regions where the uterine tubes enter. During childhood and post menopause, the body and cervix are approximately of equal length with cervix being of greater diameter (thickness). The slit like uterine cavity is approximately 6 cm in length from the external OS of the uterus to the wall of the fundus.

2. Cervix of the uterus
Approximately 2.5 cm. long in an adult non pregnant woman.
It is divided into   Supravaginal and
Vaginal parts.
The Supravaginal part is separated from the bladder anteriorly by loose connective tissue and from the rectum posteriorly by the rectouterine pouch.
The rounded vaginal part of the cervix extends into the vagina and communicates with it through the external os. The fusiform cervical canal extends from the isthmus of the uterine body to the external as of the uterus. The cervical canal is broadest at its middle part and communicates with the uterine cavity through the internal os and with the vagina through the external os.

Layers of uterus
The wall of the body of the uterus consist of 3 layers.
1) The myometrium
The middle muscular coat. It becomes greatly distended during pregnancy. The main branches of blood vessels and nerves of the uterus are located in the myometrium.
2) The endometrium
The inner mucous coat. It is firmly adherent to the underlying myometrium. The amount of muscular tissue in the cervix markedly less than in the body of the uterus. The cervix mostly fibrous and is composed mainly of collagen with a small amount of smooth muscles and elastic.

Supports of the Uterus
The uterus is a motile organ which undergoes extensive changes in size and shape during the reproductive period of life. It is supported and prevented from Sagging down by a number of factors which are chiefly muscular and fibromuscular.
Classification

I Primary supporters
A. Muscular (or active)

  • Pelvic diaphram
  • Perineal body
  • Urogenital diaphram

B. Fibro-Muscular (or mechanical)

  • Uterine axis
  • Pubocervical ligament
  • Transverse cervical ligament
  • Uterosacral ligament
  • Round ligament of uterus

II Secondary supports
are formed by peritoneal ligaments.

  • Broad ligament
  • Uterovesical fold of peritoneum
  • Rectovaginal fold of peritoneum.

Role of individual supports
1) Pelvic diaphram
Consist of 2 levator ani muscles Each levator ani muscles consists of three main divisions.

  • Pubococcygeus
  • Iliococcygeus
  • Ischiococcygeus

Pubococcygeus muscle
Arises from the posterior surface of the body of the pubic bone and passes backwards, lateral to the vagina and rectum, to be inserted into the anococcygeal raphe and into the coccyx.

Iliococcygeus
Is a fan-shaped muscle arising from a broad origin along the white line of the pelvic fascia and passing backwards and inwards to be inserted into the coccyx.

Ischiococcygeus
Muscle has a narrow origin from the ischial spine and spreads out posteriorly to become inserted into the front of the coccyx.
It supports the pelvic viscera and resists any rise in the intra abdominal pressure. If the pubococcygeus is torn during parturition the support to the vagina is lost and the latter lends to sink into the vestibule along with the uterus, thus causing prolapse of the uterus.

2) Perineal body
It is a muscular node to which a muscles are attached. It act as an anchor for the pelvic diaphram, and thus maintain the integrity.
3) Urogenital diaphram
The sphincter urethrae muscle chiefly forms the external sphincter of the urethra. However many inferior fibres of the muscle support the vagina by getting attached to its wall.
4) Uterine axis
The anteverted position of uterus will prevent the organ from sagging down.
5) Pubocervical ligaments
These ligaments connect the cervix to the posterior surface of the pubis. They are derived from the pelvic fascia.
6) Transverse cervical ligaments (of Machenrodt)
They are fan-shaped condensations of the pelvic fascia on each side of the cervix above the levator ani and around the uterine vessels. They form a ‘hammock’ that support the uterus.
7) Uterosaeral ligaments
There are also condensations of the pelvic fascia. They connect the cervix to the periosteum, of the sacrum (S2, S3) and are enclosed within the rectouterine folds of the peritoneum.
The uterosaeral ligaments keep the cervix backwards against the forward pull of the round liganent.
8) Round ligaments of uterus
The round ligaments are two fibromuscular flat bands, about 10-12 cm. long, which lie between the two layers of the broad liganent each liganent begins at the lateral angle of the uterus, runs forwards and laterally, passes through the deep inguinal ring, transverse the inguinal canal, and merges with the areolar tissue of the labium majus after breaking up into this filaments. In the inguinal canal it is accompanied by a process of the peritoneum during total life. If it persist after birth it is known in females as the canal of nuck.

Arterial Supply
The blood supply of the uterus derives mainly from the uterine arteries with an additional supply from the ovarian arteries.

Venous and lymphatic drainage
The uterine veins enter the broad ligaments with the arteries and form a uterine venous plexus on each side of the cervix. Veins from the uterine plexus drain into the internal iliac veins.
Lymphatic vessals follow 3 main routes.
Most vessels from the fundus pass to the lumbar lymphnodes, but some vessals pass to the external iliac lymphnodes or run along the round liganent of the uterus to the superficial lymphnodes.
Vessals from the uterine body pass within the broad liganent to the external iliac lymphnodes.
Vessals from the uterine cervix pass to the internal iliac and sacral lymphnodes.

Uterine tubes
the uterine tubes extend laterally from the uterine horns and opens into the peritoneal cavity near the ovaries. The uterine tubes (10cm. long) lie in the mesosalpinx formed by the free edges of the broad ligaments. The uterine tubes are divisible into 4 parts from lateral to medial.
1) The infundibulum
is the funnel shaped distal end that opens into the peritoneal cavity through the abdominal ostium the finger like processes of the fimbriated and of the infundibulum- the fimbriae spread over the medical surface of the ovary. One large ovarian fimbria is attached to the superior pole of the ovary.
2) The ampulla
The ampulla the widest and longest part, begin at the medial end of the infundibulum oocytes expected from the ovaries usually are fertilized in the ampulla.
3) The isthmus, the thick walled part, enters the uterine born.
4) The uterine part is the short intramural segment that passes through the wall of the uterus.
Arterial supply
The tubal branches arise as anastomosing terminal branches of the uterine and ovarian arteries.
Venous and Lymphatic drainage
The tubal veins drains into the ovarian veins and uterine venous plexus. The lymphatic vessels drain to the lumbar lymph nodes.
Innervation of the uterine tubes
The nerve supply derived partly from the ovarian plexus and partly from uterine plexus. 

APPLIED ANATOMY
Disease of the female reproductive system

1) Inflammation
Infection of the reproductive system may be classified as
a) Non specific
Usually caused by a mixture of microbes.Eg:- Staphylococci, coliform bacteria, clostridium perfrigens
b) Specific :caused by sexually transmitted microbes.
eg:- Neisseria gonorrhoea, Trichomonas vaginalis, Chlamydia, herpes viruses, HIV, hepatitis-B.

i) Pelvic inflammatory disease (PID)
This may be specific or nonspecific – It usually begins as vulvovaginitis, included the vulvar glands, then it may spread to the cervix, uterus, uterine tubes and overies upward spread is most common.

Complication of PID
1. Infertility due to obstruction of uterine tubes.
2. Peritonitis
3. Intestinal obstruction
4. Bacteriaemia
5. Bartholins gland abscess or cyst formation.
ii) Specific infections
In general the microbes that cause sexually transmitted diseases.
à are unable to survive outside the body for long periods.
à Have no intermediate hest
à Produce leisions in the genital area which discharge the infecting microbes.
iii) Gonorrhoea
Caused by Neisseria gonorrhoeae, which affects the mucosa of the reproductive and urinary tracts. In males suppurative urethritis occurs and the infection may spread to prostatic gland, epididymis and testes. In the female infection may spread from vulvar glands, vagina and cervix to the body of the uterus, uterine tubes, ovaries and peritoneum. Healing by fibrosis may cause obstruction in uterine tubes, leading to infertility. In males it cause urethral stricture.

iv) Syphilis
This disease is caused by Treponema pallidum. After an incubation period of several weeks the primary sore (chancre) appears at the site of infection. After several weeks the chancre subsides spontaneously. Secondary laision appear 3 to 4 months after infection. They consist of skin rashes and raised papular on the external genitalia. These subside after several months and are followed by a latest period of variable number of years. Tertiary leisions (gumma) develop in many organs and in a few cases the nervous system in involved leading to general paralysis.
v) Trichomonas Vaginalis
These protozoa cause acute vulvovaginitis.
vi) Candidiasis
candida albicans is the causative organism. It causes infection in some circumstances. eg;- in diabetes, malnutrition & general detrility.

Disorders of the cervix
a) Cervicitis
This occurs in most multiparous women and may be due to infection caused by specific or nonspecific microbes. Excessive white vaginal discharge may be the only indication in some. Chronic inflammation may follow acute attacks or develop gradually and may predispose to malignancy.

b) Cervieal intra epithdial neoplasia
A high incidence is associated with some personal and social factors.

  • Early marriage and pregnancy
  • High number of pregnancies
  • Coitus beginning at an early age
  • Frequent coitus
  • Many sexual partners
  • Sexually transmitted disease
  • Low socioeconomic status.

Disease takes. 15 to 20 years to develop and it occurs mostly between 35 and 50 years of age. It is said that herpes viruses and DNA may be involved. Dysplastic changes begin in the deepest layer of cervical epithelium. The cell dysplasia may progress to involve the full thickness of epithelium called carcinoma in situ. It may develop further and spread locally or may metastasis to other parts.

3) Disorders of the body of the uterus
a) Acute endometritis
Caused by non-specific infection following parturition or abortion. A variety of microbes may be involved as Staphylococci, Streptococci, Escherichia coli, pseudomonas. The infection may spread to
à Myometrium, perimetrium & Surrounding pelvic tissues which leads to thrombosis of illiac veins
à Uterine tubes causing salpingitis, fibrosis, obstruction and inferlity.
à It may cause peritonitis and adhesions.

b) Chronic endometritis
This may follow as an acute attack or be due to spread of PID. It may follow abortion or partorition and may be associated with chronic salpingitis, endometrial carcinoma or the use of intrauterine contraceptive devices.

c) Endometriosis
This is the growth of endometrial tissue outside the uterus most commonly in the ovaries, uterine tubes and other pelvic structures. The ectopic tissue reacts to sex hormones causing menstrual bleeding in the ovaries causing ‘chocolate cysts’. There is intermittent pain due to swelling and recurrent hemorrhage causes fibrous tissue formation. It may cause pelvic inflammation, infertility, pelvic adhesions.

d) Adenomyosis
Presence of endometrium within the myometrium. The ectopic tissue may cause general or localised uterine enlargement. The liaisons may cause dysmenorrhoea and irregular excessive bleeding.

e) Endometrial hyperplasia
The hyperplasia may affect endometrial glands, causing cyst formation or focal hyperplasia of atypical cells. The focal type frequently undergo malignant change. Both types are associated with a sustained high blood oestrogen level.
f) Leiomyoma (fibroid, myoma)
These are very common often multiple benign tumours of myometrium. Large tumours may undergo degenerative changes if they outgrow their blood supply, leading to necrosis, fibrosis, and calcification. They are hormone dependent. They tend to regress after the menopause. Large tumours may cause pelvic discomfort, frequency of micturition, menorrhagia, irregular bleeding dysmenorrhoea and reduced fertility.

g) Endometrial carcinoma
This occurs in nulliparous women between 50 and 60 years of age. The incidence is increased when an oestrogen secreting tumour is present and in women who are obese, hypertensive diabetic because they tend to have a high level of blood oestrogen. Lymphatic spread is delayed until there is extensive local spread. Distant metastases develop later, usually in liver, lungs and bones.

4) Disorders of the uterine tubes
a) Acute salpingitis
Infection usually spreads form the uterus and exeasionally from peritoneal lavity. It causes

  • unevenful recovery
  • chronic inflammation, leading to fibrous tubal obstruction and infertility.

pus formation (pyosalpinx) and further spread to ovaries and peritoneal cavity leading to fibrous tubal obstruction, infertility and pelvic adhesions.
b) Ectopic pregnancy
This is the implantation of a fertilised ovum outside the uterus, most commonly in a uterine tube. As the fetus grows the tube ruptures and its contents enter the peritoneal cavity, causing acute inflammation (peritonistis) and possibly severe intraperitoneal haemarrhage.

5) Abnormal position of uterus
a) Prolapse
Prolapse is a common complaints and severe degrees are most often seen in women of menopausal age who have borne children. In prolapse straining causes protrusion of the vaginal wall, while in severe cases the cervix may be pushed down to the level of the vulva. In extreme cases the whole uterus and both vaginal walls may be extruded. This produces micturition symptoms, low mild sacral backache, and sense of weakness and insecurity in the region of perineum. Most common cause is atomicity and asthenia that follow menopause. It may also occur after difficult labour.
b) Retroversion
Retroversion means the position where the uterus is not anteverted. There can be mobile and fixed retroversion. Fixed retroversion means that the uterus is bound by adhesions or tumours. Retroversion may cause dysmenorrhoea, menorrhagia, pressure, backache, dyspareunia, inferlity or abortion.
c) Inversion of the uterus
In inversion uterus becomes turned inside out. At first fundus is pushed down into cavity of the uterus leaving a cupshaped depression on the peritoneal surface.

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