Vagina | pacs

Fallopian

tube • Female reproductive tract vessels (Gray's illustration) - Ganzer Fall bei Radiopaedia

Hacking, C. Female reproductive tract vessels (Gray's illustration). Case study, Radiopaedia.org. (accessed on 23 Oct 2022) https://doi.org/10.53347/rID-95586 • CC by-nc-sa 3.0 (modified)

Vagina •

Midsagittal female pelvis (Gray's illustration) - Ganzer Fall bei Radiopaedia

Hacking C, Midsagittal female pelvis (Gray's illustration). Case study, Radiopaedia.org (Accessed on 07 Apr 2024) https://doi.org/10.53347/rID-184373 • CC by-nc-sa 3.0 (modified)

Radiopaedia • CC-by-nc-sa 3.0 • de

The vagina is a midline fibromuscular tubular organ positioned in the female perineum extending superiorly from the vulva, to the cervix and uterus in the pelvis.

Gross anatomy

The vagina is 8-10 cm in length, extending posterosuperior from the vestibule through the urogenital diaphragm to the uterus. The vagina forms a 90° angle with the uterus.

The vagina includes the following parts:

vaginal orifice, incompletely covered by the hymen
vault: upper end of the vagina
fornices (anterior, posterior, lateral): recesses formed as the vagina surrounds the cervix

The anterior and posterior vaginal walls are usually closely apposed, diverging at the vaginal vault and fornices. The posterior fornix is covered by the peritoneum of the anterior part of the rectouterine pouch.

The vagina is supported by various structures:

levator ani
transverse cervical ligament
pubocervical ligament
uterosacral ligament
perineal membrane and perineal body

After menopause, the vagina shortens in length and the fornices almost completely disappear.

Relations

anteriorly: cervix, bladder, urethra
posteriorly: pouch of Douglas, Denonvillier fascia, perineal body
laterally: levator ani, pelvic fascia, ureters

Arterial supply

vaginal, uterine, internal pudendal and middle rectal arteries (branches of internal iliac arteries)

Venous drainage

vaginal venous plexus draining into internal iliac veins

Lymphatic drainage

upper three-quarters: internal and external iliac, and sacral nodes
lower part (below the hymen): superficial inguinal nodes

Innervation

upper vagina: includes both parasympathetic and sympathetic innervation
- sympathetic fibers from the hypogastric plexus supply blood vessels and smooth muscle of the vaginal wall
- afferent fibers run with sympathetic nerves
lower 2-3 cm vagina: perineal and posterior labial branches of the pudendal nerve, anterior part of the vulva from the ilioinguinal nerve

Histology

Three layers:

mucosa (non-keratinized stratified squamous epithelium): is hormonally sensitive, and lubricated from the Cervical and Bartholin's glands

muscularis: connective tissue and smooth muscle (outer longitudinal and inner circular)

adventitia: endopelvic fascia that connects the vagina to surrounding pelvic structures to maintain support

Embryology

Embryological derivation of the vagina is from two parts, which is important for understanding the origin of congenital anomalies:

upper two-thirds of the vagina, cervix and uterus: all derived from the paired Mullerian / paramesonephric ducts.
lower one-third of the vagina: derived from the bilateral sinovaginal bulbs which arise from the urogenital sinus

Radiographic features

Ultrasound

During transabdominal (TA) scanning the distended bladder, which acts as an acoustic window, does not affect vaginal position. The vagina can, therefore, be used as an effective landmark, even if the uterus does not occupy its familiar position in the pelvis. The vagina is best seen with a midsagittal TA approach, with a partially-filled bladder. The vagina is hypoechoic and the mucosa is echogenic. The echogenicity of the mucosa diminishes in menopause, with the loss of estrogen stimulation.