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Nursing Notes

External Genital and Accessory Organs

Mons pubis, labia majora and minora, vestibule, clitoris and perineum, with the openings of the vestibule; then the breast as an accessory organ and where each external structure comes from.

Topic 2 of 3 · 3 min · 2 sections

1 External Genital Organs

Also known as the vulva or pudendum.

1. Mons pubis

  • Composed of a pad of subcutaneous tissue.
  • Lies in front of the symphysis pubis.
  • In the adult female it carries hair, in a triangular shape.

2. Labia majora (the outer lips)

  • Thick, elevated folds of skin and subcutaneous tissue.
  • Contain sebaceous glands, sweat glands and hair.
  • Inner surface is hairless.
  • Join medially to form the posterior commissure.
  • Homologous to the scrotum in the male.

3. Labia minora (the inner lips)

  • Thin, elevated folds of skin and subcutaneous tissue.
  • Join medially to form the fourchette — the site from which an episiotomy is made.
  • Do not contain hair.
  • Homologous to the penile urethra in the male.

Homologue and analogue

Homologue
Analogue
Same origin
Different origin
Different function
Same function

4. Vestibule

  • Triangular in shape.
  • Surrounded by: the clitoris anteriorly, the fourchette posteriorly, and the labia minora laterally.

Openings of the vestibule — four kinds, six openings in all:

RememberOpenings into the vestibule

Urethral opening1
Vaginal orifice1
Skene's gland openings2
Bartholin's gland openings2
Hymen
Partially covers the vaginal orifice. It is usually torn at first intercourse and further lacerated at childbirth; strenuous activity may tear it too. Torn, not absent.
Bartholin's glands
In the vestibule, on either side of the vaginal orifice; their ducts open at the orifice. Alkaline mucus secretion, which helps lubricate the vagina during sexual excitement. The largest vestibular gland. Homologous to the bulbourethral gland in the male.
Skene's glands
On both sides of the urethral opening. The largest paraurethral glands; they are paraurethral rather than vestibular glands. Homologous to the prostate gland in the male.

5. Clitoris

  • An elongated, elevated structure.
  • Richly supplied with nerves.
  • Length 1.5–2 cm.
  • Homologous to the penis in the male.
  • Function: sexual arousal and pleasure during intercourse.

6. Perineum

  • The space between the vagina and the rectum (anus).

2 Accessory Organs

Breast (mammary gland)

  • A biglandular structure, composed of fatty tissue and glandular tissue.
  • A modification of the sweat gland.
  • Extends from the 2nd rib to the 6th rib.
  • Function: secretion of milk during lactation.
  • 5–15 sebaceous glands are present around the nipple, invisibly.
  • Pain in the nipples is called thelalgia.
  • The beginning of breast development, or breast buds, is called thelarche, the first visible sign of puberty, with a median age of about 10–11 years. Menarche is the last, at a peak age of about 13.

Embryological origins

Structure Origin
Clitoris Genital tubercle
Labia majora Labioscrotal folds
Labia minora Genital folds
Vestibule Urogenital sinus