Uterus pdf - Pelvis - Muhadharaty

Basic Anatomy

285

The Uterine Tube as a Conduit for Infection

the uterine cavity in the wall of the uterine tube (Fig. 7.26). This

may follow, with leakage of pus into the peritoneal

tact and ascend through the uterus and enter the uterine tubes.

The uterine tube lies in the upper free border of the broad liga-

ment and is a direct route of communication from the vulva

through the vagina and uterine cavity to the peritoneal cavity.

Pelvic Inflammatory Disease

The pathogenic organism(s) enter the body through sexual con-

Salpingitis

cavity, causing pelvic peritonitis. A pelvic abscess usually fol-

lows, or the infection spreads farther, causing general peritonitis.

Ectopic Pregnancy
Implantation and growth of a fertilized ovum may occur outside

is a variety of ectopic pregnancy. There being no decidua for-

mation in the tube, the eroding action of the trophoblast quickly

destroys the wall of the tube. Tubal abortion or rupture of the

tube, with the effusion of a large quantity of blood into the

peritoneal cavity, is the common result.

ascend into the general peritoneal cavity, giving rise to severe

The blood pours down into the rectouterine pouch (pouch of

Douglas) or into the uterovesical pouch. The blood may quickly

abdominal pain, tenderness, and guarding. Irritation of the subdi-

aphragmatic peritoneum (supplied by phrenic nerves C3, 4, and 5)

ovarian follicles degenerate in the tube proximal to the obstruc

may give rise to referred pain to the shoulder skin (supraclavicu-

lar nerves C3 and 4).

Tubal Ligation

Ligation and division of the uterine tubes is a method of obtain-

ing permanent birth control and is usually restricted to women

who already have children. The ova that are discharged from the

tion. If, later, the woman wishes to have an additional child, res-

toration of the continuity of the uterine tubes can be attempted,

and, in about 20% of women, fertilization occurs.

C L I N I C A L N O T E S

Development of the Uterine Tube

coiled; differentiation of the muscle and mucous membrane

on the posterior abdominal wall on the lateral side of the

Early on in development, the paramesonephric ducts appear

mesonephros. The uterine tube on each side is formed from

the cranial vertical and middle horizontal parts of the parame-

sonephric duct (Fig. 7.27). The tube elongates and becomes

takes place; the fimbriae develop; and the infundibulum,
ampulla, and isthmus are identifiable.

E M B R Y O L O G I C N O T E S

(8 cm) long, 2 in. (5 cm) wide, and 1 in. (2.5 cm) thick. It

below the level of the internal os, where the peritoneum

The uterus is covered with peritoneum except anteriorly,

Structure of the Uterus

retroflexed.

is, in addition, bent backward on the cervix, it is said to be

If the body of the uterus

retroverted.

uterus is said to be

touterine pouch (pouch of Douglas). In this situation, the

bent backward on the vagina so that they lie in the rec

In some women, the fundus and body of the uterus are

uterus lies in an almost horizontal plane.

Thus, in the erect position and with the bladder empty, the

(see Fig. 7.25).

anteflexion of the uterus

position is termed

level of the internal os with the long axis of the cervix. This

the long axis of the body of the uterus is bent forward at the

(see Fig. 7.25). Furthermore,

anteversion of the uterus

on the long axis of the vagina. This position is referred to

In most women, the long axis of the uterus is bent forward

Positions of the Uterus

nutrition of the fertilized ovum.

The uterus serves as a site for the reception, retention, and

Function

are attached to the uterine wall just below this level.

and the round ligaments of the ovary and of the uterus

ine tubes enter the superolateral angles of the uterus,

vix is related to the lateral fornix of the vagina. The uter

as it passes forward to enter the bladder. The vaginal cer

Fig. 7.19). The supravaginal cervix is related to the ureter

the broad ligament and the uterine artery and vein (see

The body of the uterus is related laterally to

Laterally:

of ileum or sigmoid colon within it (see Fig. 7.5).

to the rectouterine pouch (pouch of Douglas) with coils

The body of the uterus is related posteriorly

Posteriorly:

is related to the anterior fornix of the vagina.

to the superior surface of the bladder. The vaginal cervix

bladder (see Fig. 7.5). The supravaginal cervix is related

to the uterovesical pouch and the superior surface of the

The body of the uterus is related anteriorly

Anteriorly:

Relations

an anterior lip and a posterior lip (see Fig. 7.25).

the external os becomes a transverse slit so that it possesses

parous woman, the vaginal part of the cervix is larger, and

the birth of the first child, the external os is circular. In a

Before

external os.

and with that of the vagina through the

internal os

nicates with the cavity of the body through the

commu

cervical canal,

7.25). The cavity of the cervix, the

section, but it is merely a cleft in the sagittal plane (see Fig.

of the uterine body is triangular in coronal

cavity

The

vaginal parts of the cervix.

aginal

suprav

anterior wall of the vagina and is divided into the

is the narrow part of the uterus. It pierces the

cervix

The

entrance of the uterine tubes.

is the part of the uterus that lies below the

body

The

entrance of the uterine tubes.

is the part of the uterus that lies above the

fundus

The

is divided into the fundus, body, and cervix (see Fig. 7.25).

and

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CHAPTER 7

The Pelvis: Part II—The Pelvic Cavity

thin-walled uterine tube

fundus of uterus

thick decidua lining

body of uterus

mucous plug

FIGURE 7.26

An ectopic pregnancy located where the ampulla of the uterine tube narrows down to join the isthmus. Note

the thin tubal wall compared to the thick decidua that lines the body of the uterus.

posterior abdominal wall

mesonephric duct

paramesonephric duct

developing ovary

ostium

paramesonephric duct

developing ovaries

vertical

horizontal

vertical

fused lower ends of

paramesonephric ducts

mesonephric duct

urogenital sinus

mesonephric duct

paramesonephric duct

gut

pelvic cavity

mesonephric duct

fused paramesonephric ducts

broad ligament

FIGURE 7.27

The relationship of the mesonephric and paramesonephric ducts to the developing ovary.

of the pelvis. Note the developing broad ligament.

Anterior view of ovaries and ducts.

developing ovary.

A. Cross section of a

C and D. Mesonephric and paramesonephric ducts in a cross section

Basic Anatomy

descending branch that supplies the cervix and the vagina.

in supplying the uterus. The uterine artery gives off a small

by anastomosing with the ovarian artery, which also assists

margin of the uterus within the broad ligament and ends

(see Fig. 7.25). The artery then ascends along the lateral

angles and reaches the cervix at the level of the internal os

ligament (see Fig. 7.19). It crosses above the ureter at right

the uterus by running medially in the base of the broad

ine artery, a branch of the internal iliac artery. It reaches

The arterial supply to the uterus is mainly from the uter

Arteries

on each side of the cervix.

It is in this fascia that the uterine artery crosses the ureter

parametrium.

ceral pelvic fascia, which is referred to as the

The supravaginal part of the cervix is surrounded by vis

cycle in response to the ovarian hormones.

trium undergoes extensive changes during the menstrual

submucosa. From puberty to menopause, the endome

metrium is applied directly to the muscle, there being no

with the mucous membrane lining the cervix. The endo

the mucous membrane lining the uterine tubes and below

It is continuous above with

endometrium.

known as the

lining the body of the uterus is

mucous membrane

The

up of smooth muscle supported by connective tissue.

is thick and made

myometrium,

muscular wall,

The

ligament.

space between the attachment of the layers of the broad

passes forward onto the bladder. Laterally, there is also a

the cervix of the uterus by the pelvic fascia (Fig. 7.28).

the anterior parts of the levatores ani muscles are attached to

mitted downward through the pelvis. The medial edges of

pelvic viscera and resist the intra-abdominal pressure trans

vic fascia on their upper surface, they effectively support the

stretching across the pelvic cavity, and, together with the pel

described in Chapter 6. They form a broad muscular sheet

The origin and the insertion of the levatores ani muscles are

The Levatores Ani Muscles and the Perineal Body

form three important ligaments.

ani muscles and the condensations of pelvic fascia, which

The uterus is supported mainly by the tone of the levatores

Supports of the Uterus

the inferior hypogastric plexuses.

Sympathetic and parasympathetic nerves from branches of

Nerve Supply

into the superficial inguinal lymph nodes.

ligament of the uterus through the inguinal canal and drain

nal iliac lymph nodes. A few lymph vessels follow the round

from the body and cervix drain into the internal and exter

nodes at the level of the first lumbar vertebra. The vessels

pany the ovarian artery and drain into the para-aortic

The lymph vessels from the fundus of the uterus accom

Lymph Drainage

internal iliac vein.

The uterine vein follows the artery and drains into the

Veins

287

Blood Supply

transverse cervical ligament

uterine artery

peritoneum

ureter

lateral fornix

levator ani

obturator internus
fascia of

obturator internus

obturator membrane

hymen

vagina

urogenital diaphragm

cervix

pelvic fascia

FIGURE 7.28

erse cervical liga

Coronal section of the pelvis showing relation of the levatores ani muscles and the transv

pelvic fascia.

ments to the uterus and vagina. Note that the transverse cervical ligaments are formed from a condensation of visceral

288

CHAPTER 7

Some of the fibers of levator ani are inserted into a

premature parturition.

tions. Severe emotional disturbance, however, can cause

thesia does not interfere with the normal uterine contrac

the extrinsic innervation. In women in labor, spinal anes

The uterine muscular activity is largely independent of

the force of the contractions of the uterine body.

that a nervous reflex mechanism is initiated and increases

ally the fetal head) starts to stretch the cervix, it is thought

withdrawal of progesterone. Once the presenting part (usu

is possible that the onset of labor is triggered by the sudden

ticularly sensitive to the actions of oxytocin at this time. It

been fully developed in response to estrogen, and it is par

By the end of pregnancy, the contractility of the uterus has

The cause of the onset of labor is not definitely known.

term.

time the pregnancy is said to be at

takes place at the end of the 10th lunar month, at which

from the genital tract of the mother. Normally, this process

baby, the fetal membranes, and the placenta are expelled

Labor, or parturition, is the series of processes by which the

Role of the Uterus in Labor

of the myometrium, although some hyperplasia takes place.

is largely a result of hypertrophy of the smooth muscle fibers

month it has reached the xiphoid process. The increase in size

month the fundus rises out of the pelvis, and by the ninth

placenta. At first, it remains as a pelvic organ, but by the third

terone, first by the corpus luteum of the ovary and later by the

result of the increasing production of estrogens and proges

During pregnancy, the uterus becomes greatly enlarged as a

Uterus in Pregnancy

no longer produce estrogens and progesterone.

and less vascular. These changes occur because the ovaries

After menopause, the uterus atrophies and becomes smaller

Uterus after Menopause

gens secreted by the ovaries.

puberty, when they enlarge greatly in response to the estro

The fundus and body of the uterus remain small until

Uterus in the Child

during pregnancy.

anteflexed (bent forward) but is considerably stretched

The Pelvis: Part II—The Pelvic Cavity

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fibromuscular structure called the

(see

perineal body

Fig. 7.5). This structure is important in maintaining the

helps keep the uterus anteverted (tilted forward) and

cutaneous tissue of the labium majus (see Fig. 7.18). It

the deep inguinal ring and inguinal canal, to the sub

between the superolateral angle of the uterus, through

remains of the lower half of the gubernaculum, extends

which represents the

round ligament of the uterus,

The

role in supporting the uterus.

become taut. Clinically, they are considered to play a minor

or pushed down for a considerable distance before they

uterus are lax structures, and the uterus can be pulled up

The broad ligaments and the round ligaments of the

either side of the rectouterine pouch (pouch of Douglas).

the lower end of the sacrum. They form two ridges, one on

pass to the cervix and the upper end of the vagina from

sist of two firm fibromuscular bands of pelvic fascia that

The sacrocervical ligaments con

Sacrocervical Ligaments

(pubovesical ligaments).

which they give some support

positioned on either side of the neck of the bladder, to

cervix from the posterior surface of the pubis. They are

sist of two firm bands of connective tissue that pass to the

The pubocervical ligaments con

Pubocervical Ligaments

vagina from the lateral walls of the pelvis.

vic fascia that pass to the cervix and the upper end of the

cervical ligaments are fibromuscular condensations of pel

Transverse

Transverse Cervical (Cardinal) Ligaments

and keeping the cervix in its correct position (Figs. 7.28

vagina and play an important part in supporting the uterus

cles. They are attached to the cervix and the vault of the

pelvic fascia on the upper surface of the levatores ani mus

These three ligaments are subperitoneal condensations of

Sacrocervical Ligaments

The Transverse Cervical, Pubocervical, and

the uterus.

levatores ani and thus supports the vagina and, indirectly,

and the anal canal. It is slung up to the pelvic walls by the

The perineal body lies in the perineum between the vagina

during childbirth, prolapse of the pelvic viscera may occur.

integrity of the pelvic floor; if the perineal body is damaged

and 7.29).

bladder

pubocervical ligament

transverse cervical
ligament

sacrocervical ligament

rectum

cervix

rectum

transverse cervical ligament

pubocervical ligament

bladder

sacrocervical
ligament

FIGURE 7.29

Ligamentous supports of uterus.

visceral pelvic fascia.

Lateral view. These ligaments are formed from

As seen from below.

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CHAPTER 7

The Pelvis: Part II—The Pelvic Cavity

Brief Summary of the Implantation of the Fertilized

blastocyst sinks beneath the surface epithelium and becomes

line (see Fig. 7.34). As the result of the enzymatic digestion of

Ovum in the Uterus

The blastocyst enters the uterine cavity between the fourth

and ninth days after ovulation. Normal implantation takes

place in the endometrium of the body of the uterus, most fre-

quently on the upper part of the posterior wall near the mid-

the uterine epithelium by the trophoblast of the embryo, the

embedded in the stroma by the 11th or 12th day.

E M B R Y O L O G I C N O T E S

Vagina

childbirth, the hymen usually consists only of tags.

which is perforated at its center. After

hymen,

called the

vaginal orifice in a virgin possesses a thin mucosal fold

anterior, posterior, right lateral, and left lateral. The

nices:

surrounds the cervix, is divided into four regions, or

Figs. 7.5 and 7.28). The area of the vaginal lumen, which

pelvic floor and the lower half lies within the perineum (see

remember that the upper half of the vagina lies above the

downward and backward into the vagina. It is important to

end, the anterior wall is pierced by the cervix, which projects

terior walls, which are normally in apposition. At its upper

measures about 3 in. (8 cm) long and has anterior and pos

backward from the vulva to the uterus (see Fig. 7.5). It

The vagina is a muscular tube that extends upward and

Location and Description

for-

uterine tube

urogenital sinus

vaginal plate

uterine tube

body

cervix

uterus

sinovaginal bulb

vaginal plate

urogenital sinus

fundus

body

cervix

lateral fornices

of vagina

hymen

urogenital sinus

hymen

vestibular glands

labium minus

labium major

vestibule

FIGURE 7.33

Formation of the uterine tubes, the uterus, and the vagina.