Pelvis and Perineum Flashcards
Name the masses of erectile tissue forming the penis.
Corpora cavernosa along the dorsal part of the body of the penis, corpus spongiosum forming the bulb and ventral part and glans, and surrounding the urethra.
What is the bit of the corpus cavernosum that’s attached to the ischiopubic ramus called?
The crus (plural = crura).
What muscle surrounds the penile crura?
Ischiocavernosus muscle.
Which muscle surrounds the bulb of the penis?
Bulbospongiosus muscle.
What is the muscle called that stabilises the perineal body in the centre?
Superficial transverse perineal muscles.
What is the closed sac of peritoneum on the anterolateral side of the testis called?
Tunica vaginalis.
Where is the ampulla of the ductus deferens?
Between the ureters and the ejaculatory duct.
Where is the prostate gland?
Immediately inferior to the bladder, posterior to the pubic symphysis and anterior to the rectum.
Where are the seminal vesicles?
At the base of the back of the urinary bladder, joining the ductus deferens to from the ejeculatory duct which penetrates through the back of the prostate gland.
What are the four sections of the male urethra, and what type of epithelium lines them?
1) Prostatic - transitional epithelium
2) Membranous - pseudostratified columnar epithelium
3) Bulbar (spongy/penile) - pseudostratified columnar epithelium
4) Pendulous (spongy/penile) - pseudostratified columnar epithelium (except stratified squamous in navicular fossa)
Name the most superior part of the uterus, and then the two parts more inferior to it.
Fundus, body, cervix.
What is the fold of peritoneum connecting the uterus to the walls and floor of the pelvis called?
Broad ligament.
What are the three parts of the broad ligament of the uterus?
Mesometrium - mesentery of uterus.
Mesovarium - mesentery of ovaries.
Mesosalpinx - mesentery of uterine tube.
Which is the ligament of the uterus that runs through the inguinal canal?
Round ligament
What is the pouch behind the uterus and in front of the rectum called, and what is its significance?
The rectouterine peritoneal pouch (Pouch of Douglas) which is the lowest part of the abdominal cavity when a woman is standing upright.
What is the pouch in front of the uterus and behind the bladder called?
Uterovesical peritoneal pouch.
What are the 4 parts of the uterine tubes?
Isthmus, ampulla, infundibulum, fimbriae.
What is the ligament called formed by peritoneum surrounding ovarian vasculature?
Infundibulopelvic ligament (suspensory ligament of ovaries).
Which part of the broad ligament is the ovary attached to?
The posterior layer.
What do you call the bit attaching the ovary to the upper part of the uterus?
Ovarian ligament.
What are the outer folds of the vulva called that develop from the genital swellings?
Labia majora.
What are the inner folds of the vulva called that develop from the urethral fold?
Labia minora.
What is the name for the opening of the vagina?
Introitus.
What is the name for the clitoral hood?
Prepuce of the clitoris.
What is the name for the opening of the urethra in the woman?
External urethral meatus.
What are the recesses around the cervix called?
Anterior, posterior, and lateral fornix.
What structure is the posterior fornix in close proximity to?
Rectouterine peritoneal pouch.
What is the name of the meeting place of muscles just anterior to the external anal sphincter?
Perineal body.
What develops from the pubic tubercle in men and in women?
Men = glans penis Women = glans clitoris
What is the remnant of the zipped up urethral groove in men?
Raphe
What develops from the genital swelling in men?
Scrotum.
What muscle attaches the crura of the corpora cavernosa to the ischiopubic rami?
Ischiocavernosus muscle.
What muscle covers the bulb of the penis in men, and bulb of the vestibule in women?
Bulbospongiosus muscle.
Which muscles attach to the ischiotuberosities and the perineal body?
Superficial transverse perineal muscles.
Which is the major somatic nerve of the perineum, and from which spinal segments does it arise?
Pudendal nerve, arising from S2, S3, S4 (sacral plexus).
Where does the parasympathetic innervation of the perineum come from?
The pelvic splanchnic nerves from spinal segments S2-S4 (which enter the inferior hypogastric plexus).
Where does the sympathetic innervation of the perineum come from?
Fibres from spinal segments T10-L2.
What is the main artery supplying the perineum and what is the exception?
Internal pudendal artery, except testicular arteries which arise from abdominal aorta.
What is the main vein draining the perineum and what is the exception?
Internal pudendal vein, except deep dorsal vein of penis which drains into prostate plexus and so may mix with venous anastomoses of the vertebral column.
What are the boundaries of the pelvic inlet?
The pubic symphysis, promontory of the sacrum, arcuate line on the ilium.
What are the boundaries of the pelvic outlet?
Pubic symphysis, coccyx, ischiopubic rami, sacrotuberous ligaments.
What comprises the pelvic region of the vertebral column?
The sacrum and coccyx.
Where is the pubic crest?
Medial to the pubic tubercle.
What is the pectineal line?
A ridge on the superior ramus of the pubic bone.
What is the arcuate line?
A smooth rounded border on the internal surface of the ilium, forms part of the pelvic inlet.
What comprises the iliopectineal line?
Arcute line of ilium and pectineal line.
What do you call the large triangular surface on either side of the body of the base of the sacrum, which forms part of the pelvic inlet?
Ala (plural = alae) of the sacrum.
What do you call the bit of the sacrum formed by the base of the sacrum tilting forwards internally, which also forms part of the pelvic inlet?
Promontory of the sacrum.
Name the gap between the superior and inferior pubic rami?
Obturator foramen.
Which structure separates the greater and lesser sciatic notches?
Ischial spine.
Which ligaments define the sciatic foramina
The sacrospinous ligament between the sacrum and ischial spine. The sacrotuberous ligament between the sacrum and ischial tuberosities.
What is the subpubic angle?
The angle at which the inferior pubic rami converge at the pubic symphysis to form the pubic arch.
What are 5 structural differences between the male and female bony pelvis?
- The male has a prominent sacral promontory, the female has a blunt sacral promontory
- The male has a narrow heart shaped pelvic inlet, the female has a wide oval/round pelvic inlet
- The male has a narrow subpubic angle (90 degrees)
- The male has prominent and inwardly pointing ischial spines, the female has blunt and outwardly pointing ischial spines
- The male has a concave sacral curvature, the female has a flattened sacral curvature
Which muscle originates on the obturator membrane, lies on the anterolateral wall of the pelvis, and exits through the lesser sciatic foramen to attach to the upper femur?
Obturator internus muscle.
Which muscle originates on the anterior sacrum, lies on the posterior wall of the pelvis and exits through the greater sciatic foramen to attach to the upper femur?
Piriformis muscle.
Which nerve runs in the lateral wall of the pelvis deep to the ovarian fossa, so can become irritated in ovarian pathology and refer pain the the upper medial thigh?
Obturator nerve.
What structure does the obturator nerve pass through to exit the pelvic cavity?
Obturator canal.
What are the three components of the levator ani muscle?
Pubococcygeus
Iliococcygeus
Puborectalis
Where is the perineal body?
The central tendon in the midline of the junction of the urogenital and anal triangles.
What structure is the posterior fornix directly related to?
The rectouterine pouch
What 6 things comprise the broad ligament of the uterus?
Mesovarium, mesosalpinx, mesometrium, infundibulopelvic (suspensory) ligament, round ligament of the uterus (remnant of embryonic gubernaculum), ovarian ligament
What is the point of reference for the position of the uterus?
The axis of the cervical canal.
What are the four different positions of the uterus?
Anteverted, anteflexed, retroverted, retroflexed
What are the three layers of the uterus wall?
Perimetrium (peritoneal covering), myometrium (smooth muscle), endometrium
What are the two layers of the endometrium?
Stratum basale, stratum functionale (shed in menstruation)
What are two features of the endometrium?
Uterine glands, spiral arteries
What is the opening of the cervix into the vaginal canal called?
External os
What is the recess around the margins of the cervix called?
Anterior, posterior and lateral fornix
What is the epithelial transition zone, and what is it called when it is further out and visible?
Where the simple columnar epithelium of the cervical canal changes to stratified squamous epithelium of the vagina. When it is not in the cervical canal it is called an ectropion.
Which artery supplies the ovary?
Ovarian artery which is a branch of the abdominal aorta
Which arteries supply the uterus and vagina?
Uterine artery, vaginal artery, internal pudendal artery
What is the upper and lower border of the perineum?
The perineum is between the pelvic diaphragm and the superficial skin and fascia
What does the imaginary line between the ischial tuberosities split the perineum up into?
Anterior urogenital triangle, posterior anal triangle
What is the region between the perineal membrane and it’s covering connective tissue called?
Deep perineal pouch.
What are the fat filled spaces called between the pelvic diaphragm, perineal membrane, and obturator internus?
Ischio-anae fossae
Where is the superficial perineal pouch?
Between the perineal membrane and the subcutaneous fascia and skin.
Where is the greater vestibular gland?
In the superficial perineal pouch, on the posterior of the bulb of the vestibule
What are the labia majora and scrotum both embryological derivatives of?
Genital swellings
What are the clitoris and glans penis both embryological derivative of?
Genital tubercle
What supplies most of the perineum’s somatic innervation, and where does it arise?
Pudendal nerve, arises from the sacral plexus from spinal segments S2, S3, S4. It runs around the ischial spine (out the greater sciatic foramen and in through the lesser sciatic foramen) and into the ischio-anal fossae.
Where does the parasympathetic innervation for the perineum come from?
From the pelvic splanchnic nerves which arise from spinal segments S2 - S4 and run to the inferior hypogastric plexus.
Where does sympathetic innervation for the perineum come from?
Spinal segments T10-L2.
What is the main artery supplying the perineum, and what is the exception in men and women?
Interior pudendal artery, which follows a similar course to the pudendal nerve.
In women the exception is the ovaries which are supplied by the ovarian artery from the abdominal aorta. The uterine and vaginal arteries branch off the internal iliac with the internal pudendal.
In men the exception is the testes which are supplied by the testicular artery which branches off the abdominal aorta.
Which is the main vein draining the perineum, and what is the exception in men and in women?
Internal pudendal vein.
Exception in men = deep dorsal vein of penis, which drain into prostatic plexus
Exception in women = deep dorsal vein of clitoris, which drains into the vesicle plexus of the bladder
What do you call the outgrowth of the embryonic gut just in front of the cloaca, which is fluid filled and important in vertebrae which develop in eggs to store waste?
Allantois
What is septation of the cloaca?
The septa grows down to divide the Y shaped cloaca into the urogenital sinus, and the rectum.
What is the other name for the definitive adult kidney?
Metanephros
What forms the precursor of the epididymis in the male?
The collecting duct system left behind by the degenerated mesonephros
Where does the vas deferens run?
From the tail of the epididymis, up through the inguinal canal, over the ureters and around the back of the bladder to join the seminal vesicles and form the ejaculatory duct
What are the two zones the prostate gland can be divided into and what are their significance?
The central zone which surround the urethra - hypertrophy is more typically benign, but quickly puts pressure on the urethra and interrupts urine flow
The peripheral zone - hypertrophy is more typically carcinoma than benign
Where is the external urethral sphincter?
The deep perineal pouch
What forms the margins of the pelvic outlet?
Pubic symphysis anteriorly, coccyx posteriorly, ischial tuberosities laterally, ischiopubic rami, sacrotuberous ligaments
What muscles make up the pelvic diaphragm?
Coccygeus, levator ani (iliococcygeus, pubococcygeus, puborectalis)
What 4 things does the perineum contain?
Anal canal
External genitalia
Distal urethra
Spaces in-between containing blood vessels, nerves, fat
Which line divides the urogenital triangle and anal triangle?
Imaginary line between ischial tuberosities
What are the two holes in the pelvic diaphragm called?
Urogenital hiatus, anal hiatus
Where does the coccygeus muscle run to and from?
From the coccyx to the ischial spine
What is the purpose of the pelvic diaphragm?
Keeping the abdominal viscera inside the abdominal cavity against gravity
What do you call the thick fibrous sheet over the urogenital triangle?
Perineal membrane
What is the perineal membrane attached to?
Posterior free border is attached in the midline to the perineal body, attached laterally to the ischiopubic rami, gap between it and the pubic symphysis at the front
What do the ischoanal fossae allow?
Movement of the pelvic diaphragm, and expansion of the anal canal during defaecation
What is contained in the superficial perineal pouch?
Erectile tissue and associated skeletal muscle
What is the name given to the line remaining along the corpus spongiosum, from the zipping up of the urethral groove when the genital tubercle and anterior urethral folds hypertrophy to form the penis?
Raphe
What are the three pairs of muscles in the superficial perineal pouch?
Superficial transverse perineal muscles
Ischiocavernosus muscles
Bulbospongiosus muscles
Name the muscle covering the testes and spermatic cord (just superficial to the tunica vaginalis).
Cremaster muscle
Name the connective tissue that surrounds the erectile tissue and inside the testes.
Tunica albuginea
What supports the superior aspect of the uterus?
Broad ligament, round ligament
What supports the middle aspect of the uterus?
Cardinal, pubocervical, uterosacral ligaments
What supports the inferior aspect of the uterus?
Pelvic floor structures - levator ani, perineal membrane, perineal body
Where does the round ligament of the uterus (remnant of the embryonic gubernaculum) arise and run?
Attaches to uterine horn, runs through inguinal canal to attach to labia majora.
What are the cardinal/transverse cervical ligaments and where do they run?
The cardinal ligaments are along the inferior border of the broad ligament and house the uterine artery and uterine veins.
They run from the lateral fornix to the lateral pelvic wall at the level of the ischial spines.
Where do the pubocervical ligaments attach?
They support the uterus by attaching the cervix to the posterior of the pubic symphysis.
Where do the uterosacral/rectouterine ligaments attach?
They support the uterus and hold it in place by attaching the cervix to the sacrum.
What is the ligament called that attaches the coccyx to the margin of the anus?
Anococcygeal ligament
Which ligament provides the main abdominal support for the uterus?
Cardinal/transverse cervical ligaments
