Female perineum Flashcards
Summarise the perineal spaces (or pouches)
Perineal membrane (PM): Thick triangular fascial structure attached to pubic arch. Posterioly free margin. Anteriorly a small gap.
Deep perineal space: is above the PM and below fascia of pelvic diaphragm.
Superficial perineal space: is below PM and perineal fascia (subcutaneous tissue)
These spaces are potential spaces and they become real only when for eg: fluid leaks into them
What is the mons pubis
the fatty tissue anterior to the pubic symphysis, covered by hairy skin, continues posteriorly on each side of the vaginal opening as the labia majora
List the muscles in the deep perineal pouch in females
external urethral sphincter- as in men - Compress the membranous urethra as internal sphincter less well developed in females
deep transverse perineal- as in men
compressor urethrae
sphincter urethrovaginalis
Describe the compressor urethrae
arises from the ischiopubic ramus on each side
blends with partner on the other side anterior to the urethra
innervated by perineal branches of the pudendal nerve (S2-S4)
functions as the accessory sphincter of urethra
Describe the sphincter urethrovaginalis
arises from the perineal body and passes forward to the vagina to blend with its partner on other side anterior to the urethra
innervated by the perineal branch of the pudendal nerve (S2-S4)
Functions as an accessory sphincter of the urethra (also may facilitate closing the vagina)
Describe the importance of the perineal body
Ill-defined but important connective tissue structure into which muscles of the pelvic floor and the perineum attach
It is positioned in the midline along the posterior border of the perineal membrane, to which it attaches
the posterior end of the urogenital hiatus in the levator ani muscles is also connected to it.
The deep transverse perineal muscles intersect at the perineal body; in women, the sphincter urethrovaginalis also attaches in the perineal body. Other muscles that connect to the perineal body include the external anal sphincter, the superficial transverse perineal muscles, and the bulbospongious muscles of the perineum
Summarise the contents of the superficial perineal pouch in women
Median erectile tissue masses (corpus spongiosum) In females it divides around the vestibule to form vestibular bulbs. The glans of clitoris is derived from this.
Lateral erectile tissue masses (corpora cavernosa) Paired cylinders, attached to ischiopubic rami. The body of clitoris is derived from these.
These erectile tissues within perineum are surrounded by skeletal muscles
List the contents of the superficial perineal pouch in females
Vulva = collective name for female external genitalia: mons pubis, labia majora & minora, clitoris, vestibule of vagina, vestibular bulbs, vestibular glands
Summarise the perineal membrane in females
As in the male, the perineal membrane fills the urogenital triangle. The erectile tissues and associated skeletal muscles are anchored to this.
Describe the erectile tissue in females
In women a pair of erectile structures, termed the bulbs of vestibule, are situated, one on each side, at the vaginal opening and are firmly anchored to the perineal membrane,
Small bands of connective tissue connect the anterior ends of these bulbs to a single, small, pea-shaped erectile mass, the glans clitoris, which is positioned in the midline at the end of the body o the clitoris and anterior to the opening of the urethra.
Describe the clitoris
Composed of two corpora cavernosa and the gland clitoris
As in the penis it has an attached part (root) and a free part (body)
Unlike the root of the penis, the root of the clitoris technically consist only of the two crura (although the bulbs of the vestibule are attached to the glans clitoris by thin bands of erectile tissue, they are not included in the attached part of the clitoris
the body of the clitoris, which is formed only by the unattached parts of the two corpora cavernosa, angles posteriorly and is embedded in the connective tissue of the perineum
What is the body of the clitoris supported by
A suspensory ligament that attaches superiorly to the pubic symphysis.
The glans clitoris is attached to the distal end of the body and is connected to the bulbs of the vestibule by small bands of erectile tissue
The glans clitoris is exposed in the perineum and the the body of the clitoris can be palpated through skin
Describe the superficial features of external genitalia in females
In women, the clitoris and vestibular apparatus, together with a number of skin and tissue folds, form the vulva
On either side of the midline are two thin fold of skin, termed the labia minora
The region between them and into which the urethra and vagina open is the vestibule
Describe the labia minora
Anteriorly, they bifurcate, forming a medial and lateral fold
medial forms unite to form the frenulum of the clitoris, that joins the glans clitoris
the lateral folds unite ventrally over the glans clitoris and body of clitoris to form the prepuce of clitoris (hood)
posterior to the vestibule, the labia minora unite, forming a small transverse fold, the frenulum of the labia mnora (the fourchette)
lateral to the labia minora are two broad fold, the labia majora, which unite anteriorly to form the mons pubis
What is found in the vestibule
The vaginal orifice is surrounded by varying degrees of a ring-like fold of membrane, the hymen, which may have a central perforation or may completely close the vaginal opening
Following rupture of the hymen (resulting from first sexual intercourse or injury), irregular remnants of the hymen fringe the vaginal opening
Describe the hymen
Hymen- The vaginal orifice in a virgin possesses a thin mucosal fold , the hymen. It is normally perforated at the centre. Following intercourse and child birth the hymen is torn and only a few tags may remain
What does the posterior part of the corpus spongiosum form
The posterior part of the corpus spongiosum forms two large vestibular bulbs surrounding the lower vestibule and vagina
Describe the glands associated with the urethra and vagina
The orifices of the urethra and vagina are associated with the openings of glands
ducts of the para-urethral glands (Skene’s glands) open into the vestibule, one on each side of the lateral margin of the urethra
The ducts of the greater vestibular glands (Bartholin’s ducts) open adjacent to the posterolateral margin of the vaginal opening in the crease between the vaginal orifice and remnants of the hymen
Summarise the glands in the vagina and in the urethra
Greater vestibular gland (Bartholin’s) and lesser vestibular glands (Skene’s) open into the vaginal vestibule. Peri-urethral glands open into the urethral lumen.
The Vaginal wall mucosa does not have any glands. The wall is kept moist my transudation.
The cervical canal mucosa has numerous mucus glands which are active in pre-menopausal women.
Describe the urethra in women
Urethra: passes directly inferiorly from the bladder, with a poorly developed internal sphincter in females, so a well developed external sphincter in the deep perineal pouch - approx 4cm long
Skene’s glands drain via a duct and open into the lateral margin of the external urethral orifice
Describe the nerves of the pelvis
Pelvic contents supplied by autonomic nerves only
Sympathetic from lower thoracic and upper lumbar segments T10 - L2 via hypogastric plexus
Parasympathetic from S2-4 outflow
Pelvic sensation is visceral and poorly localised - pain referred to suprapubic region and perineum
Summarise the nerves of the pelvis
Pelvic and perineal nerves: 1) Pelvic sympathetic – T10 - L2 via hypogastric plexus; 2) Pelvic parasympathetic – sacral outflow from S2-S4 3) Perineum (somatic) – Pudendal nerve S2-S4
Summarise the nerves of the perineum
Pudendal nerve S2-S4: main somatic nerve of the perineum. Motor to perineal muscles, anal & urethral sphincters, levator ani, Sensory to external genitalia (vestibule, labia minora and part of labia majora, lower vagina, clitoris, lower anal canal,
Summarise the lymphatic drainage of pelvis and perineum
Pelvic organs drain mainly to external and internal iliac nodes (around the arteries)
Ovary and testis drain to para-aortic nodes
Perineum (including anal canal) and external genitalia drain to superficial inguinal nodes (subcutaneous below inguinal ligament).
Describe the arteries that supply erectile tissues in women
arteries of bulb of vestibule- bulb of vestibule and related vagina
deep arteries of clitoris- crura and corpus cavernosum of body
dorsal arteries of clitoris- surrounding tissue and the glans
Describe the consequence of lymphatic drainage of the testes
Drain via channels that ascend in the speramtic cord
pass through inguinal canal and course up the posterior abdominal wall to connect directly with lateral aortic or lumbar nodes and pre-aortic nodes around the aorta, approximately at levels L1 and L2
Therefore disease from the testes tracks to nodes high in the posterior abdominal wall and not inguinal or iliac nodes
