RCA: Pelvis

• Ala of the sacrum
• S1 body (sacral promontory)
• Sacroiliac joint
• Anterior superior iliac spine
• Ischial spine
• Obturator foramen
• Ischial tuberosity
• Pubic symphysis
• Pubic tubercle
• Arcuate line

• Pubic symphysis
• Pubic tubercle
• Ischial tuberosity
• Coccyx
• Sacrum
• Sacrotuberous ligament
• Ischiopubic ramus

• Sacral promontory
• Lumbosacral joints
• Sacral canal
• Sacral foramina
• Median sacral crest
• Coccyx

• Greater Sciatic foramen
• Sacrospinous ligament
• Sacrotuberous ligament
• Lesser sciatic foramen
• Piriformis
• Obturator internus

• Pelvic floor: separates pelvic cavity from perineum, and supports pelvic organs
• Levator ani muscle; including
• - Iliococcygeus muscle
• - Puboccygeus muscle
• - Puborectalis muscle
• Coccygeus muscle
• raphe

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• Anterior ‘U’ shaped defect (for passage of urogenital structures); this defect is supported by the perineal membrane and muscles
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• Urethral opening
• Vaginal opening
• Perineum

• Perineal membrane
• The perineum is the region below the pelvic floor and between the thighs
• - It is bounded by the pelvic outlet and divided into two triangular regions
• Urogenital triangle
• Anal triangle

• Rectouterine pouch (of Douglas) in women
• Vesicouterine pouches in women
• Rectovesical pouch only in men
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• uterine tube
• rectum
• ovary
• bladder
• round ligament

• Fundus and body of uterus
• Isthmus
• Ampulla
• Infundibulum
• Fimbriae
• Ureter
• Cervix with canal
• Broad ligament
• Mesovarium
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• A pelvic organ in the adult, which expands into the abdomen when full but an abdominal organ in the infant.
• Ureters
• Apex
• Base; faces posteroinferiorly
• Median umbilical ligament
• Opening of ureters
• Trigone; smooth part
• Internal urethral orifice

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• Bladder neck supported by pubovesical ligament in women
• Prostate supported by puboprostatic ligament in men
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• The ureter is crossed near the base of the bladder by the vas deferens in men and the uterine arteries in women (“water under the bridge”).
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• There are 3 parts of the male urethra;
• - Prostatic
• - Membranous
• - Spongy; bulbar and penile parts
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• Internal urethral sphincter
• Urethral crest
• Openings of prostatic ducts
• Veru montanum; seminal colliculus
• Ejaculatory ducts; either side of
• prostatic utricle
• Bulbourethral glands
• External urethral sphincter; around membranous part of urethra
• - not to be confused with orifice; i.e. on the tip of the penis = narrowest part of penis
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• Females: ~4cms long- opens into vestibule between labia minora

Rectum: ~15cms long, Extends from S3 to levator ani where the anorectal angle is formed (posterior to anterior)

• Superior rectal artery: from the inferior mesenteric artery (singular)
• Middle rectal artery: from internal iliac artery (x2)
• Inferior rectal artery: from internal pudendal artery from internal iliac artery (x2)
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• Superior rectal vein: from the inferior mesenteric vein
• Middle rectal vein: to
• internal iliac vein
• Inferior rectal vein: to internal pudendal vein to internal iliac vein

• External anal sphincter: is smooth muscle (autonomic innervation).
• Internal anal sphincter: is skeletal muscle (pudendal nerve)
• Puborectalis part of levator ani
• Submucosal venous plexus; origin of haemorrhoids
• Anal column
• Anal valve
• Dentate (pectinate) line
• Anal verge

• Perineum & external genitalia: the region below the pelvic floor and between the thighs, which are bounded by the pelvic outlet and divided into two triangular regions
• Perineal membrane: A triangular membrane attached to the pubic arch with a free posterior border
• - Has a thin region immediately above it called the deep perineal 'pouch'
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• - Provides attachments for perineal muscles and the roots of the external genitalia
• - Perforated by urethra in both sexes and by vagina in females
• Levator ani
• Perineal body: small fibromuscular region at the centre of the perineum where the posterior border of the perineal membrane, perineal muscles & levator ani muscles converge

• External urethral sphincter
• Deep transverse perineal muscle
• Ischiocavernosus
• Bulbospongiosis muscle
• Superficial transverse perineal muscle

• Crus of clitoris: attached part of corpus cavernosum
• Bulb of vestibule
• Bartholin’s glands
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• Crus of penis: attached part of corpus cavernosum
• Bulb of penis: attached part of corpus spongiosum

• Glans clitoris
• Labium majus
• Urethral opening
• Labia minora surrounding
• the vestibule
• Vaginal opening; introitus
• Hymen
• Fourchette

• Corona of glans
• Prepuce (foreskin)
• Urethral meatus; external urethral orifice
• Frenulum
• Glans penis

• Posterior trunk: giving rise to the
• - Superior gluteal artery
• Umbilical artery; giving rise to
• - Superior vesical artery
• Anterior trunk: giving rise to
• - Obturator artery
• Uterine/vaginal artery (women) or
• Inferior vesical artery (men): supplies branches to the prostate (in men), bladder, ureter, seminal vesicle
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• Inferior gluteal artery
• Middle rectal artery
• Internal pudendal artery

• Pelvic veins: rich venous plexuses surround the bladder, rectum, prostate, uterus & vagina
• - NB bleeding with pelvic trauma
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• Pelvic lymph nodes: alongside iliac arteries draining to pre- and para-aortic nodes
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• External iliac lymph nodes: receive vessels from the inguinal nodes, external genitalia, vagina, and cervix; they drain into the common iliac nodes.
• Internal iliac and sacral lymph nodes: receive afferents from all the pelvic viscera (e.g., cervix, prostate, and rectum) and from the perineum, buttock, and thigh; they drain into the common iliac nodes.
• Common iliac lymph nodes drain the two preceding groups and send their efferents to the lumbar group of aortic nodes, which also receives the afferents of the testis and ovary.

• Sacral plexus: consist of somatic nerves which are formed from anterior rami of S1-4 with contributions from L4,5
• - supplies lower limbs, pelvis & perineum
• - lies on piriformis
• Lumbosacral Trunk
• Pudental nerve
• Coccygeus
• Levator ani
• Tendinous arch
• Obturator internus
• Sciatic nerve
• Inferior gluteal nerve
• Piriformis
• Obturator nerve (from lumbar plexus)
• Superior gluteal nerve

• Pudendal nerve: THE nerve to the perineum
• - supplies the external sphincters and levator ani
• - supplies perineal muscles
• - sensory to perineum
• Inferior rectal nerve
• Perineal nerve
• Dorsal nerve of clitoris/penis

• Superior hypogastric plexus
• Hypogastric nerves
• Inferior hypogastric plexus: an autonomic plexus of parasympathetic and sympathetic nerves
• Pelvic splanchnic nerves: parasympathetic nerves from S2,3,4
• - ascend to hindgut via hypogastric nerves and descend to rectum, prostate, vagina, uterus, bladder, perineum (penis/clitoris)
• Sympathetic nerves come directly from sacral sympathetic trunk and descend from superior hypogastric plexus via the hypogastric nerves

• Pelvic splanchnic nerves (S2,3,4) convey visceral sensation from bladder and motor to detrusor smooth muscle (the outer largely longitudinally arranged musculature of the bladder wall called also detrusor muscle)
• - External urethral sphincter (voluntary control - pudendal nerve S2,3,4)
• Voiding: abdominal muscles contract, detrusor contracts, urethral sphincters relax
• Initially reflex emptying but later under higher CNS control
• Female urethra empties by gravity; male assisted by bulbospongiosus contraction.

• Parasympathetics: from pelvic splanchnic nerves (S2,3,4) enter inferior hypogastric plexus and pass through deep perineal pouch to erectile tissues.
• - Produce vasodilatation of branches of internal pudendal artery & erection (penis/clitoris)
• Sympathetic nerves: via inferior hypogastric plexus produce emission and contraction of internal urethral sphincter
• Pudendal nerve (S2,3,4): sensation from penis/clitoris
• - cyclical contraction of ischiocavernosus and bulbospongiosus muscles (orgasm)

• The cervix drains to internal iliac lymph nodes (lymphatics passing with uterine vessels),
• external iliac nodes (via lymphatics in the broad ligament) and
• presacral lymph nodes

• Anteriorly: in males, Prostate and seminal vesicles (if they are diseased)
• - vagina, cervix of uterus and rectouterine pouch of douglas
• Laterally: ischial spine and tuberosity
• Posteriorly: anterior surface of sacrum and Coccyx

• Anteriorly: cervix and uterus
• - posterior surface of bladder and urethra
• Laterally: ischial spine and enlarged ovaries
• Posteriorly: rectum and rectouterine pouch of douglas

• The internal anal sphincter is supplied by sympathetic nerves (contraction) and parasympathetic nerves (S2-4, relaxation) from the inferior hypogastric plexus on the side wall of the pelvis overlying the iliac vessels.
• The external anal sphincter is supplied by the inferior rectal branch of the pudendal nerve (S2-4).

• The external urethral sphincter in both sexes is innervated by the perineal branch of the pudendal nerve (S2-4).
• The internal urethral sphincter in the male (poorly developed in females) is supplied mostly by sympathetic nerves from the inferior hypogastric plexus