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Forth stage
Obstetric
Lec-1
.د
ولدان
1/1/2016
Female reproductive anatomy
External genitalia.
Internal genitalia.
External genitalia:
Vulva:
It includes the mons pubis, the labia majora and minora, the opening into both vagina and
urethra, the clitoris, hymen, vestibule and Bartholine glands.
Mons pubis:
Is a triangular eminence in front of the pubic bones that consists of adipose tissue covered
by hair bearing skin up to its junction with the abdominal wall. Inferiorly it divides to become
continuous with labium majus on each side.
Labia majora:
Are pair of fibro-adipose folds of skin that extend from the mons pubis. They include the
terminal extension of the round ligament. They are covered by hairy skin and are rich in
sebaceous, sweat and apocrine glands.
Labia minora:
Are two hairless thin skin folds. It lies between the labia majora. They are separated into two
folds as they approach the clitoris anteriorly. The anterior folds unite to form the prepuce of
the clitoris. The posterior folds form the frenulum of the clitoris.
They contain sebaceous glands but have no adipose tissue.
Clitoris:
Is an erectile organ that is about 1-2 cm in length. It consists of 2 crura and 2 corpora
cavernosa and is covered by a sensitive rounded tubercle (the glans).
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The vestibule:
Is the cleft between the labia minora. The urethra, the ducts of the bartholine's glands and
the vagina open in the vestibule.
Vaginal orifice:
Is surrounded by the hymen which is a thin fold of mucous membrane. There are openings
in it to allow menses to escape. Any tags remaining after rupture are known as carunculae
myrtiformes.
Bartholine glands:
Each about the size of a small pea, lie at the base of each bulb and open via 2 cm duct into
the vestibule between the hymen and the labia minora. These are mucous secreting glands
producing copious amount during intercourse to acts as lubricants.
The perineal body:
Is a perineal mass of muscular tissue that lies between the anal canal and the lower third of
the vagina. Its apex is at the lower end of the rectovaginal septum and its base is covered
with skin and extends from the fourchette to the anus.
The urethral orifice:
Is immediately anterior to the vaginal orifice, about 2-3cm beneath the clitoris. The skene
(Para urethral) gland duct presents an opening on its posterior surface.
Internal reproductive organs:
1-The Vagina:
Is a hollow fibromuscular tube extending from the vulval vestibule to the uterus. It is lined
with stratified sequamous epithelium. It is attached at its upper end to the uterus just above
the cervix. The space between the cervix and vagina are known as the anterior, posterior and
lateral vaginal fornices.
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The vagina has anterior and posterior wall. The vaginal walls are normally in apposition.
Because the vagina is attached at a higher point posteriorly than anteriorly, the posterior
vaginal wall is about 2-3cm longer than the anterior wall.
The mid vagina is a transverse slit and the lower portion is an H shape in transverse section.
The vaginal walls are rugose, with transverse folds make the vagina a distensible organ which
is most evident during childbirth.
There's no gland in the vagina but it is kept moist by secretions from the uterine and cervical
glands and by some transudation from its epithelial lining.
Estrogen hormone is very important for the presence of glycogen in the vagina. This glycogen
is converted to lactic acid; by the action of Doderlein's bacilli (this bacillus is a normal co
mensal of the vagina); producing a PH of a round 4.5. This has a protective role for the vagina
in decreasing the growth of pathogenic organism.
Anteriorly the vagina is in relation to the base of the urinary bladder. Posteriorly the upper
vaginal wall forms the anterior peritoneal reflection of the pouch of Douglas. The middle 1/3
is in relation with rectum and separated from it by the rectovaginal fascia. The lower 1/3 is
in relation to the perineal body.
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-The uterus:
Is fibromuscular organ usually divided into a lower cervix and upper corpus or uterine body.
In reproductive life it is about 70 gm in weight and 7.5cm x 5cm x 3cm in dimension.
a-Cervix:
Is narrower than the body of the uterus approximately 2.5cm in length. It consists of two
parts:
Supravaginal part: lies in continuation with isthmus, lined with columnar epithelium. The
ureter run about 1cm laterally.
Vaginal part: protruding into the vagina, lined with stratified sequamous epithelium. The
upper part of the cervix mostly consist of involuntary muscles, where as the lower part is
mainly fibrous connective tissue. The sequamocolummar junction is also known as the
transformation zone which is the common site of cervical carcinoma. The beginning and the
end of the endocevical canal are called the anatomical internal and external os respectively.
The epithelium of the endocervix is cylindrical and also ciliated in its upper 2/3 and change
to stratified sequamous epithelium around the region of the external os.
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b-Corpus:
The body varies in size and shape, depending on hormonal and child bearing status. At birth,
the cervix and corpus at about equal in size, in adult women the corpus has grown to 2-3 time
the size of the cervix. The corpus is divided into several different regions isthmus or lower
uterine segment and on each side of the upper uterine body, a funnel shaped area receives
the insertion of the fallopian tubes and is called the uterine cornu; the uterus above this area
is the fundus.
The uterus consists of three layers:
1. The outer serous layer (peritoneum).
2. The middle muscular layer (myometrium).
3. The inner mucous layer (endometrium).
3-The fallopian tubes:
The fallopian tubes and ovaries are referred to as the adenexa. The fallopian tubes are paired
hollow structures. They vary in the length from 7 to 12 cm, and their function includes ovum
pick up, provision of physical environment for conception, transport and nourishment of the
fertilized ovum. Each tube has 4 identified parts:
Interstitial portion: lies within the wall of the uterus.
Isthmus: is the narrow portion adjoining the uterus.
Ampulla: is the widest and longest portion.
Infundibulum: is the funnel shaped opening of the tube and is surrounded by finger like
processes, called fimbriae.
4-The ovaries:
They are paired gonadal structures that lie suspended between the pelvic wall and the uterus
by the infundibulopelvic ligament laterally and uteroovarian ligament medially. Inferiorly the
bilateral hilar surface of each ovary is attached to the broad ligament by its mesentery
(mesovarium).
The size of the ovaries depends on the age and stage of the menstrual cycle. They are almond
shaped, solid, grayish-pink and approximately 3 cm long, 1.5 cm wide and 1 cm thick. The
ovary covered by a single layer of flattened cuboidal cells. The ovary consists of a cortex and
medulla. The cortex is composed of specialized stroma and follicles in various stages of
development. The medulla occupies a small portion of the ovary in its hilar region and is
composed primarily of fibromuscular tissue and blood vessels.
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The blood supply:
The vulva: pudendal artery (internal iliac artery).
The pelvic viscera: continuous arterial cascade connects the ovarian artery (aorta), uterine
and vaginal arteries (internal iliac artery) on the lateral border of the adnexia, uterus and
vagina.
The lymphatic drainage:
Vulva, lower 1/3 of vagina→ superficial inguinal and femoral lymph node (LN).
Uterus, cervix, upper 2/3 of vagina→ internal iliac, obturator and external iliac LN,
common iliac and Paraaortic LN.
Few vessels at the fundus→ follow the ovarian channels and some along the round
ligament to the inguinal nodes.
Ovaries and fallopian tubes→ paraaortic LN nodes.
The nerve supply of pelvis:
Nerve supply of vulva and perineum.
Pudendal nerve (S2, 3, 4) divide into perineal n. supply the vulva. The dorsal n. of the
clitoris (sensory).
Sensory fibers from the mons and labia also pass in the ilioinguinal and genitofemoral
n. to the 1
st
lumber n.
Posteriofemoral cutaneous n.carries sensation from perineum to the small sciatic n.
and thus to the S1, 2, 3.
Nerve supply of the pelvic viscera
Nerve fibres of the pre aortic plexus of the sympathetic nervous system are continuous
with those of the superior hypogastric plexus which divides, on each side its fibres
continuous with the uterovaginal plexus.
Parasympathetic fibres from S2,S3,S4 join the uterovaginal plexus. Fibres from (or to)
the bladder, uterus, vagina & rectum join the plexus.