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Nursing Notes

Internal Genital Organs and Ligaments

Vagina, uterus, fallopian tubes and ovaries: their parts, measurements, angles and functions, then the five ligaments that support the uterus and the peritoneal pouches around it.

Topic 3 of 3 · 4 min · 3 sections

1 Internal Genital Organs

1. Vagina

  • Also known as the birth canal, or colpos.
  • The organ of copulation.
  • Composed of stratified squamous epithelium.
  • Length: anteriorly 7 cm, posteriorly 9 cm.
  • A fibromuscular tube extending from the vulva to the uterus (cervix).
  • Angle of the vagina with the horizontal: 45°.
  • pH of the vagina: 3.8–4.5 (acidic).
  • Normal flora: Döderlein's bacilli (lactobacilli). Glycogen is converted by Döderlein's bacilli into lactic acid, which keeps the vagina acidic. Oestrogen deposits the glycogen into the vagina.
  • Female urethra 4 cm; male urethra 20 cm.
Fornix / fornices
The space between the vaginal wall and the cervix (ectocervix). Four in number: 1 anterior, 1 posterior, 2 lateral.

2. Uterus

  • Also known as the womb, hystera, or metra. In Hindi, गर्भाशय.
  • A hollow, muscular, pyriform (pear-shaped, नाशपाती) organ situated in the pelvis, with the bladder in front and the rectum behind.
  • Measurement: 8 × 5 × 1.25–2.5 cm (length × width × thickness), or 3 × 2 × 1 inch.
  • Weight: 50–80 g, average 60 g when non-pregnant; 900–1000 g when pregnant.

Parts of the uterus

Fundus1.5 cmBody3.5–4 cmIsthmus0.5 cmCervix2.5 cm04 cm
Parts of the uterus by length, drawn to scale.
Cervix
Divided by the vagina into a supravaginal part and a vaginal part. Separately, the endocervix is the lining of the cervical canal (columnar epithelium) and the ectocervix is the surface facing the vagina (squamous epithelium). The two divisions are not the same thing.

Layers of the uterus

  • Perimetrium — the outer layer, a serous layer.
  • Myometrium — the middle muscular layer. The thickest layer of the uterus; helps in movement.
  • Endometrium — the inner layer, a mucous layer. It has two layers: the functionalis layer, which sheds during menstruation, and the basalis layer. During pregnancy the endometrium is called the decidua.
Position of the uterus
Anteverted and anteflexed.
Position Angle Between
Anteverted 90° Vagina and uterus (cervix)
Anteflexed 120° Fundus and cervix

3. Fallopian tube

  • Also known as the salpinx, or the uterine duct/tube. It develops from the Müllerian duct — that is its embryological origin, not another name for it.
  • 10 cm long, in four parts.
Part Length Diameter
Interstitial / intramural — the narrowest part 1.25 cm 1 mm
Isthmus 2.5 cm 2 mm
Ampulla — the longest and widest part 5 cm 1 cm
Infundibulum 1.25 cm 6 mm
  • The site of fertilisation is the ampulla.
  • Two openings: the uterine opening (ostium), which opens into the uterus, and the pelvic or abdominal ostium, which is surrounded by at least 20–25 finger-like projections (fimbriae). One of these reaches the ovary — the ovarian fimbria.

4. Ovary

  • A paired, oval-shaped structure.
  • Pinkish grey in colour.
  • The fundamental, or primary, sex organ.
  • Measurement: 3 × 2 × 1 cm (length × width × thickness).
  • Weight: 2–3 g (about 0.07–0.11 ounce).
  • The ovary and testes are homologues — they develop from the same gonadal ridge.

Functions

  1. Primary function — ovum production (oogenesis).
  2. Secondary function — secretion of hormones (oestrogen and progesterone).

2 Ligaments of the Uterus

1. Broad ligament

Supports the uterus, fallopian tube and ovary. It consists of three ligaments:

  • Mesometrium — support to the uterus.
  • Mesosalpinx — support to the fallopian tube.
  • Mesovarium — support to the ovary.

2. Round ligament

  • Gives support to the uterus only.
  • Attaches from the cornua of the uterus.
  • Other names for the cornua: pacemaker of the uterus, uterine horn, tubal ostia.

3. Transcervical ligament

  • The true support of the uterus.
  • Also known as the cardinal ligament, or Mackenrodt's ligament.
  • Supports the uterus horizontally.

4. Uterosacral ligament

  • Support between the uterus and the sacrum.
  • Prevents anterior deviation of the uterus.

5. Pubocervical ligament

  • Support between the symphysis pubis and the cervix (uterus).
  • Prevents posterior deviation of the uterus.

3 Peritoneal Pouches

  1. Vesicouterine pouch — the pouch between the urinary bladder and the uterus.
  2. Rectouterine pouch — the pouch between the rectum and the uterus. Also known as the pouch of Douglas, or the cul-de-sac.