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External Genital Organs (Syn: Vulva, Pudendum)

The vulva includes mons veneris, labia majora, labia minora, clitoris, vestibule and conventionally the perineum

Description: 7

The vulva

  • "Mons Pubis (Veneris): Pad of subcutaneous adipose connective tissue lying in front of the pubis and in the adult female covered by hair.
  • Labia Majora: Lie on either side; join posteriorly to form the posterior commissure.
  • Their inner side is hairless. It is analogous to the scrotum in male. The round ligament terminates at its anterior third.
  • The labia majora and the mons veneris contain:
    • The hair follicles.
    • The sebaceous glands.
    • Modified sweat glands known as the apocrine glands.
  • Labia Minora: They are two thick folds of skin, devoid of fat, lying within the labia majora. Anteriorly, they enclose the clitoris and unite with each other in front and behind the clitoris to form the prepuce and the frenulum, respectively. Lower portion of the labia fuse across the mid line to form a fold of skin called the fourchette. It is analogous to the ventral aspect of the penis.
  • Clitoris: It is a small erectile body (2.5 em) lying in the anterior-most part of the vulva. It is analogous to the male penis. It consists of glans, a body and two crura.
  • Vestibule: Triangular space bounded anteriorly by the clitoris, posteriorly by the fourchette, and on either side by the labia minora. It has 4 openings namely
    1. Urethral opening.
    2. Vaginal orifice opening.
    3. Bartholin's ducts on either side.
    4. Ducts of paraurethral glands also called as Skene's ducts.

Extra Edge


Vulva: Collective name for external genitalia and perineum.


The Hidradenoma of vulva arises from the apocrine glands of labia majora and mons veneris.

Development of Vulva : Clitoris develops from genital tubercle.

Labia minora genital folds.


Labia majora genital (Iabio scrotal) swellings.


Vestibule urogenital sinus.


  • Blood Supply mainly by Internal pudendal artery (branch of internal iliac artery) and from superficial adn deep pudendal artery (branches of femoral artery).
  • Sensory innervation: Anterosuperior part is supplied by the cutaneous branches from the ilioinguinal and genital branch of genitofemoral nerve (L 1 and L2) and the posteroinferior part by the pudendal branches from the posterior cutaneous nerve of thigh (52,3,4). Between these two groups, the vulva is supplied by the labial and perineal branches of the pudendal nerve (S2,3,4).
  • Lymphatic drainage: Inguinal nodes (superficial and deep).

Extra Edge:

  • The Posterior part of vestibule between fourchette and vaginal opening is called as fossa navicularis.
  • Hymen is thin fold of mucous membrane attached to vaginal orifice all around.
  • It is lined by stratified squamous epthelium on both sides.
  • The hymen is most commonly torn posterolaterally or posteriorly.
  • It is replaced by tags after childbirth called as carunculae myrtiformes.

Internal Genital Organs

The internal genital organs in female include vagina, uterus, fallopian tubes, and the ovaries.


  • Distensible fibromuscular canal connecting the uterine cavity with the exterior at the vulva.
  • Anterior wall = 7.5 em, posterior wall = 9 em in length.
  • Upper vagina is separated by cervix into anterior, posterior and lateral fornices.
  • Deepest fornix = posterior fornix; Shallowest = anterior fornix

Relations of Vagina

Anterior Bladder (upper third)


                 Urethra (lower two third)


Posterior P = Pouch of douglas in the upper 1/3rd


                  A = Ampulla of rectum in middle 1/3rd


                  P = Perineal body in lower 1/3rd


Lateral Medicos = Mackenrodts ligament or pelvic cellular tissue


                Love = Levator ani muscle


                Books = Bulbocavernous muscle


                Vestibular bulb


                Bartholin's glands


                From above downwards

Description: 5


Description: 6

The cervix and all 4 fornices are related to:

  • Uterine vessels
  • Mackenrodt's ligament
  • Ureter"

Posteriorly surrounding the pouch of douglas, lies the uterosacral ligament.

  • Vagina has inhabitant bacteria called as Doderlein's bacteria which is a lactobaccilliv and converts the glycogen present in vaginal epithelium into lactic acidvunder the influence of estrogen.
    Thus, pH of vagina is acidic
    • The pH of vagina in an adult woman is 4-5.5 with an average of 4.5.
    • The pH of vagina varies with age.

Note: Doderlein's bacilli are present in newborn females' vagina and then, disappear (after 10-14 days) to appear at puberty and then again disappear after menopause.

Age Vaginal pH Doderlein’s bacteria
In a newbom infanta Between 4-5 Present
6 weeks old child Changes from alkaline to acidic Absent
Puberty 4-5.5 Sparse
Reproductive age group 3.5--4.5 Plenty
Pregnancy 6-80 Plenty
Late post menopausal"   Absent

pH of vagina also varies along its length, being highest in the upper part because of admixture of alkaline cervical mucus.

  • Vagina does not have any mucous secreting glandsf
  • Vagina does not have any serosal covering except for the area covered by cui de sac posteriorly.
  • Apart from Doderlein's bacilli, it contains many other pathogenic organism including Cl. welchii.

Vaginal Epithelium

Vagina is lined by stratified squamous epithelium which is composed of the following types of cells:

  • Parabasal/basal cells: Which are predominant when there is no hormonal dominancef
  • Intermediate cells: Which are predominant when there is progesterone predominance i.e. in luteal phase/later half of menstrual cycle.
  • Superficial cells: Which are predominat when there is estrogen predominance, i.e. in follicular phase - first half of menstrual cycle.
    - The intermediate and superficial cells contain glycogen under the influence of estrogen.
    Note: In newborn females, vagina is lined by transitional epithelium


  • 8 ern long x 6 ern wide x 3-4 ern in breadth.
  • Its weight varies from 50-80 g.
  • Position of Uterus-Most cornmon is anteverted and anteflexed. Anteflexion is at the level of the Internal os.
  • It Consists of :
    1. body
    2. isthmus
    3. cervix.


The wall of body consists of three layers:

  1. Perimetrium: Serous coat adherent to underlying muscle.
  2. Myometrium: Consisting of thick bundle of muscle which form 3 distinct layers during pregnency.
    1. Outer longitudinal.
    2. Inner circular.
    3. Middle interlacing called as living ligature.
  3. Endometrium: It is the mucous lining of the cavity. As there is no submucous layer, the endometrium is directly attached to the muscle coat. It consists of lamina propria and surface epithelium. The surface epithelium is a single layer of ciliated columnar epithelium.

Note: For supports of uterus see chapter on prolapse.

Since vagina does not have any glands, vaginal discharge is not derived from vagina.


The components of vaginal secretion are derived from:

  • Endocervical glands
  • Endometrial glands
  • Bartholin's glands

Vaginal cytology gives a fair idea about the hormonal status and in turn about ovulation/ovarian cycle.

Angle of Anteversion: Angle between cervix and vagina (Remember V for version V for vagina) = 90°


Angle of Anteflexion: Angle between cervix and uterus = 120° - 130°

Middle layer of uterus is called as living ligature, since it has fibers in criss-cross manner. Therefore, after the delivery of placenta, uterus contracts and these fibers occlude the blood vessels preventing postpartum hemorrhage (PPH). This is the reason w en tone of uterus is lost (atonic uterus), this action cannot take place and PPH occurs.


M/c site for cancer cervix/ClN is transformation zone.

In erect posture, the internal os lies on the upper border of the symphysis pubis and the external as lies at the level of ischial spines.

Transverse vaginal septum mostly corresponds to External os.


Age Corpus/Cervix ratio
Before puberty 1.2
At puberty 2.1
In adults/Reproductive age 3.1 or 4:1
After menopause Whole of uterus and cervix atrophy


  • Constricted (0.5 em) part of uterus situated between body of uterus and cervix.
  • It extends from anatomical internal os above to the histological os below.
  • Isthmus forms the lower uterine segment (LUS) after the 12th week in pregnancy.
  • It is best formed in late pregnancy.

Description: 8


  • It is the lowermost part of the uterus extending from the histological internal os to the external os
  • It is cylindrical in shape measuring 2.5 em in length and diameter.
  • The cervix is divided into a supravaginal part (Endocervix) - the part lying above the vagina and a vaginal part (Portio vaginalis or exocervix) which lies within the vagina, each measuring 1.25 cm.
  • Endocervix is lined by single layer of tall columnar epitheliumf and has complex racemose glands secreting alkaline mucous (pH 7.8)P Portio vaginalis or exocervix is lined by stratified squamous epitheliumf The place where columnar epithelium gradually changes to squamous epithelium is called as squamocolumnar junction/fransformation zone.

External OS

Description: 10


Internal os



Significance of internal os

  • Area between anatomical and histological internal os is called as isthmus.
  • At the level of internal os uterine artery moves upwards.
  • Peritoneum is reflected at this level on to the bladder. This is. the point of identification of internal os during lower segment caesarean sections (LSCS).
  • Uterosacral ligaments lie at this level and Mackenrodts ligament lies below this level.

Cervical Mucus

pH = 7.8 (Alkaline).


Characteristics of Cervical mucus :


Under the influence of oestrogen

(In follicular phase/proliferative phase)

Under the influence of progesterone

(in luteal phase/secretory phase)

Cervical mucus is:

  • Copious
  • Clear and watery
  • Elastic, can be stretched upto a distance of 10 cm (called as spin barkeit, stretchability)
  • Has increased water and electrolyte content, decreased protein content
  • When dried and seen under low power micro- scope it shows characteristic fern pattern


Cervical mucus is:

  • Scanty
  • Thick tenacious
  • Loses its stretchability property and fractures on stretching (called as tack)
  • Has increased protein content and decreased water and electrolyte
  • On drying and seeing under low power microscope loses its ferning pattern

Fallopian Tube

Important facts about fallopian tube:

  • Length = 4 inches or 10-12 cm.
  • Parts are:
    • Interstitium (Intramural): 1.25 cm long and 1 nun diameter (narrowest part).
    • It has no longitudinal muscles, only circular muscles are presentf
    • Isthmus: 2.5 cm long and 2 nun in diameter-' (second narrowest part)
    • Ampulla: widest? and longest part (5 cm) and fertilization occurs here
    • Pimbria/infundibulum'e 1.25 em long with a maximum diameter of 6 nun
  • Histologically: Fallopian tube is lined by columnar epithilium with a unique type of cell called as Peg cell. whose function is not known

Other important questions on fallopian tube:

  • M/c site for fertilization = ampulla of fallopian tube.
  • M/c site for ectopic pregnancy = ampulla of fallopian tube.
  • M/c site for tubal abortion = ampulla of fallopian tube.
  • M/c site for tubal rupture = isthmus of fallopian tube.
  • M/c site for tubectomy = isthmus.
  • Best prognosis for reversibility/recanalization of tube is isthmo- isthmic part of tube.

Bartholin's Glands

  • Bartholin's Glands are homologus to Cowper's glandv /bulbo-urethral glands in males.
  • They are 2 in number and of racemose type
  • Lie in the superficial perineal pouch embedded in the posterior part of vestibular bulb.
  • Glands are oval in shape and are of size of a pea
  • They are impalpable unless enlarged.
  • The acini is lined by single layer of low columnar or cuboidal cells
  • Bartholin's duct is 2 cm long? and opens into the vestibule, outside the hymen at the junction of the anterior 2/3rd and posterior 1/3rd in the groove between the hymen and labium minora
  • Duct is lined by multilayered columnar epitheliums (not by transitional epithelium as is usually stated)
  •  Function of the gland is to produce abundant alkaline mucus during sexual excitement.

Uterine appendages/ adnexa - (Note adnexa is obsolete term used for uterine appendages) viz.


Round ligament.      Ovarian ligament.       Fallopian tube.       Broad ligament.

Bartholin's cyst - formed when Bartholin's duct is blocked.

  • M/c cyst of vulva.
  • M/c cause = gonococcal infection.
  • M/c site = fluctuant, non-tender, swelling present on inner side of junction of anterior 2/3'd with posterior 1 /3,d of the labium majora.
  • TOC = Marsupialization Bartholin abscess.
  • Management = Incision and drainage.

Lining epithelium of the organ is important because

  • M/C histological type of cancer depends on lining epithelium, e.g., M/C variety of fallopian tube cacer is adenocarcinoma as tube is lined by columnar epithelium.
  • M/C variety of uterine cancer is adenocarcinoma of the uterus (lining epithelium columnar).
  • M/C variety of vaginal cancer is squamous cell carcinoma (lining epithelium is squamous cell)
  • In cervix endocervix is lined by columnar epithelium and exocervix by squamous epithelium.
  • Hence, in all females there is a zone where one epithelium changes into other, this is called as transformation zone. Since here one type of epithelium is changing into other type, it is the M/C site for cancer cervix
  • M/C variety of cancer cervix is squamous cell cancer
  • Now since endocervix is lined by columnar epithelium, adenocarcinoma can also occur in cervix. The M/C
  • site for adenocarcinoma of cervix is endocervix.

Skene's Tubules

Skene's tubules are the paraurethral glands equivalent to prostrate in males. Both Bartholin's glands and skene's tubules arise as down growths of urogenital sinus.


  • Measures 3 x 2 x 1 cm.
  • They are intraperitoneal structures lieing in the ovarian fossa on the lateral pelvic wall.
  • The ovary is attached to the posterior layer of the broad ligament by the mesovarium, to the lateral pelvic wall by infun-dibulopelvic ligament and to the uterus by the ovarian ligament.
  • The ovarian fossa is related superiorly to the external iliac vein, posteriorly to ureter and internal iliac vessels and laterally to the peritoneum separating the obturator vessels and nerve
  • The ovary is covered by a single layer of cubical cell known as germinal epithelium.
  • The substance of the gland consists of outer cortex and inner medulla Cortex consists of stromal cells which are thickened beneath the germinal epithelium to form tunica albuginea. During reproductive period the cortex is studded with numerous follicular structures. Medulla consists of loose connective tissue. It has cells called "hilus cells" which are homologous to the interstitial cells of the testes.

Lining of Female Genital Tract


Epithelial lining

  • Bartholin's gland
  • Bartholin's duct (Jeff coate 71e, p 24)
  • Adult vagina
  • Newborn vagina.
  • Uterus
  • Cervix (endocervix, cervical canal)
  • Ectocervix
  • Fallopian tube
  • Single layer of low columnar cell
  • Multilayered columnar cells (Not transitional)
  • Stratified squamous epithelium
  • Transitional epithelium
  • Columnar epithelium
  • High columnar epitheluim
  • Squamous epithelium
  • Ciliated columnar epithelium


The ureter is recognized by the following features:


  1. Pale glistening appearance.
  2. Longitudinal vessels on the surface.
  3. Peristalsis.

Uterine artery crosses the ureter at the base of broad ligament i.e, ureter lies posterior to uterine artery at this level.


Hypogastric/Internal iliac lymph nodes Found below the bifurcation of common iliac artery.


Drain- -Boqy of uterus -Cervix - Upper2/3rdofvagina - Bladder

Sentinel lymph node the lymph node which is first to receive drainage from a malignancy and is the primary site of nodal metastasis. In female genital tract cancers sentinel Iymphnode biopsy is most useful in vulval cancer followed by cervical cancer.


In vulval cancer - Sentinel lymph node is superficial inguinal lymph node.


In cervical cancer - Parametrial or paracervical lymph node (also called as uretric lymph nodes).

Pelvic Ureter

  • It extends from its crossing over the pelvic brim up to its opening into the bladder.
  • Measures 13-15 ems in length and has a diameter of 5 mm.
  • The ureter enters the pelvis in front of the bifurcation of the common iliac artery anterior to the sacroiliac joint. As it courses downwards, it lies anterior to the internal iliac artery medial to the obturator nerves and vessels and forms the posterior boundary of ovarian fossa.
  • On reaching the ischial spine, it lies over the pelvic floor and as it courses forwards and medially on the base of the broad ligament, it is crossed by the uterine artery anteriorly.
  • Soon, it enters into the ureteric tunnel and lies close to the supra vaginal part of the cervix, about 1.5 cm lateral to it.
  • After traversing a short distance on the anterior fornix of the vagina, it enters into the wall of the bladder obliquely and opens into the base of the trigone.
  • In the pelvic portion, the ureter is comparatively constricted: .
    • Where it crosses the pelvic brim.
    • Where crossed by the uterine artery.
    • In the intravesical part.
  • Blood supply of the ureter is from nearly all the visceral branches of the anterior division of the internal iliac artery (uterine, vaginal, vesical, middle rectal, and superior gluteal). The venous drainage corresponds to the arteries.
  • The lymphatics from the lower part drain into the external and internal iliac lymph nodes and the upper part into the lumbar lymph nodes.
  • Nerve supply: Sympathetic supply is from the hypogastric and pelvic plexus; parasympathetic from the sacral plexus.

Pelvic Floor (Syn: Pelvic Diaphragm)

Pelvic floor is a muscular partition which separates the pelvic cavity from the anatomical perineum. It consists of the two levator ani muscles composed of pubococcygeus, Iliococcygeus, and coccygeous muscle.

Levator ani muscle

Description: 3


Relations of superior surface of pelvic diaphragm Ureter lies on the floor in relation to the lateral vaginal fornix. The uterine artery lies above and the vaginal artery lies below it.

  • Origin: It arises from the back of the pubic rami, from the condensed fascia covering the obturator internus (white line) and from the inner surface of the ischial spine.
  • Insertion: The fibres of pubococcygeus arch backwards and medially. The anterior fibres pass across the sides of the vagina to end in the perineal body. They form the pubovaginalis muscle. The intermediate fibres pass across the sides of the rectum and become continuous with those of the opposite side behind the anorectal junction.
  • They form the puborectalis. They merge with the internal and external sphincters of the anal canal to form the anorectal ring. The most posterior fibres are attached to the coccyx, and to a fibrous band called the anococcygealligament.
  • Coccygeus: It is triangular in shape. It arises from apex of ischial spine and sacrospinous ligament and is inserted to the sacrum and coccyx.


As seen on the surface of the body, the perineum is the region where the external genitalia and the anus are located. Anatomically, the perineum is bounded above by the inferior surface of the pelvic floor, below by the skin between the buttocks and thighs. Laterally, it is bounded by the ischiopubic rami, ischial tuberosities and sacrotuberous ligaments and posteriorly, by the coccyx.

Perineum is rhomboid in shape, and can be divided into anterior and posterior triangular areas. These are the urogenital triangle placed anteriorly, and the anal triangle placed posteriorly


Urogenital Triangle

  • The urogenital triangle is placed between the two ischiopubic rami.
  • Stretching transversely across the rami, there are three membranes between which are enclosed' two spaces as shown in 1.8. From above downwards, the membranes are as follows:
    • Part of the pelvic fascia, constitutes the superior fascia of the urogenital diaphragm.
    • The second membrane is the inferior fascia of the urogenital diaphragm. It is thick and is also called the perineal membrane.
    • The most superficial membrane is the membranous layer of superficial fascia.
  • Between the upper and middle membranes, there is the deep perineal space (or pouch). The deep perineal has pouch the following muscles - deep transverse perinei (paired) and sphincter urethrae membranaceae
  • Between the middle and lower membranes, there is the superficial perineal space (or pouch). The superficial perineal pouch has superficial transverse perinei (paired), bulbocavernosus covering the bulb of the vestibule, ischiocavernosus (paired) covering the crura of the clitoris and the Bartholin's gland (paired).
  • Posteriorly, all the three membranes are attached to the perineal body and to each other thus closing the superficial and deep perineal spaces behind.

Description: 4

The Perineal Body

The perineal body (or central tendon of the perineum) is a fibromuscular body placed in the median plane at the junction of the anal and urogenital triangles.


It is pyramidal in shape and has all the 3 layers of muscles, i.e.

  • Levator ani
  • Deep transverse perinei
  • Superficial muscles except Ischiocavernous
  • Fibres of external anal sphincter.

Description: 1

Broad Ligament

  • It is a double fold of peritoneum extending from side of uterus to lateral pelvic wall.
  • Does not support the uterus

Description: 2



Pelvic Cellular Tissue

  • The pelvic cellular tissue condenses at many plaes and gives rise to
  • Uterosacral ligament that extends from 52' 53' and 54 to the posterior and lateral part of supravaginal cervix.
  • Cardinal liagments/Mackenrodts ligaments/transverse cervical ligaments that extends in fan-shaped manner from pelvic wall and inserted into the lateral supravaginal cervix.
  • Pubocervicalligament extend from arterolateral aspect of cervix to the back of pubic bone lateral to pubic symphysis.


  • Support the pelvic organs.
  • Form a protective sheath for blood vessels and ureter.

Round Ligament

Paired ligaments (10-12 ems). One end is attached at the cornu of the 'uterus and other end terminates in the anterior third of the labium majus.

Some Important Measurements



Isthumus which forms lower uterine segment

Female urethra

Posterior vaginal wall

Anterior vaginal wall

Uterus (Nulliparous)


35-40 mm

11.5 cm


8 cm x 6 cm x 4 cm



Fallopian tube

Mature ovum

Mature/ripe graffian follicle

Just before ovulation site of graffian follicle

2.5-3.5 cm

3 x 2 x 1 cms

10-12 cm

120-140 microns


16-24 mm (=20 mm)

Some important angles to remember:

Angle of anteflexion (angle between cervix and uterus)

Angle of anteversion (angle between cervix and vagina)

Urethrovesical angle




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