Pelvic Vasculature and Perineum Flashcards
What regions does the internal iliac artery supply?
Pelvic viscera, pelvic walls, perineum, and gluteal region
Divides into anterior and posterior divisions
What are the branches of the posterior division of the internal iliac artery?
Iliolumbar Artery - iliac fossa and lower lumbar region
Lateral Sacral Artery - supplies radicular branches to anterior spinal artery
Superior Gluteal Artery - Supplies gluteal muscles
What are the branches of the anterior division of the internal iliac artery?
Obturator artery - medial thigh
Umbilical Artery - Patent, upper part of urinary bladder
Inferior Vesical Artery - Only in males, base of bladder, prostate and seminal vesicles
Middle Rectal Artery - often absent, especially in females
Vaginal Artery - equivalent to inferior vesical artery in males
Uterine Artery - Crosses superior to ureter
Inferior Gluteal
Internal Pudendal
What is the perineum?
Diamond-shaped region of the true pelvis inferior to the pelvic diaphragm
What are the boundaries of the perineum?
A-P: Pubic symphysis to tip of coccyx
Lateral: Pubic Arches, Ischial rami, Ischial tuberosities
Transverse line divides it into urogenital and anal triangle
What is the urogenital triangle?
Anterior triangle: contains urogenital structures such as root of penis; vulva, urogenital diaphragm
What is the anal triangle?
Posterior triangle: contains anal canal and adjacent external anal sphincter
Borders:
Posterior: coccyx tip
Lateral: Sacrotuberous ligament
What is the ischioanal fossa and its borders?
Wedge-shaped space
Borders
Base: Skin surrounding anus
Lateral: obturator internus
Medial: Levator ani
What are the contents of the ischioanal fossa?
Pudendal nerve and internal pudendal artery and vein
Pudendal canal - fascial canal within obturator internus fascia
What is the pudendal nerve?
Formed from S2-S4
Somatic nerve that provides innervation to most of perineum
What are the branches of the pudendal nerve?
Inferior rectal nerve - external anal sphincter and lower half of anal canal
Perineal nerve - motor to pernial muscles and posterior scrotum/labia
Dorsal nerve of the penis/clitoris
What are the branches of the internal pudendal artery?
Inferior rectal artery
Branches to structures of urogenital triangle
What are the contents of the anal triangle?
Pudendal nerve
Internal Pudendal artery
Associated veins
Anal Canal
What are the boundaries of the urogenital triangle?
Posterior: imaginary line between the ischial tuberosities
Lateral - inferior rami of pubis and ramus of ischium
What is the urogenital diaphragm?
Located inferior to the pelvic diaphragm
Functions to prevent herniation (prolapse) of bladder, prostate, and uterus
Urethra and vagina both pass through diaphragm
What are the layers of the urogenital diaphragm?
Superior Fascial Layer
Deep Perineal Pouch
Inferior Fascial Layer
What is the deep perineal pouch?
Lies between the superior and inferior fascial ayers of the urogenital diaphragm
Consists of striated muscles and bulbourethral glands(males)
Branches of pudendal nerve and internal pudendal vessels
What are the contents of the deep perineal pouch?
Deep transverse perineal muscle
External Urethral Sphincter
Males - Membranous urethra,Bulbourethral glands,
Internal pudendal artery/vein/nerve
Females - Urethra, Vagina, Internal neurovasculature
Inferior Fascial Layer (Perineal membrane)
What is the superficial perineal pouch?
Space in the urogenital triangle between the inferior fascial layer and superficial perinial fascia
What are the contents of the superficial perineal pouch?
Roots of external genitalia
Superficial transverse perineal muscle
Bulbospongiousus
Ischiocavernosus
Greater vestibular glands (female)
What is the superficial perineal fascia?
Continuation of scarpa’s fascia around the penis and into the urogenital triangle
What is the root of the penis divided into?
Crura - paired, laterally placed erectile tissues
Bulb - centrally placed erectile tissue, contains proximal portion of spongy part of the urethra
What muscles are associated with the root of the penis?
Bulbospongiosus muscle - aids in emptying urethra
Ischiocavernosus muscle - aids in erection
What is the body of the penis divided into?
Corpora cavernosa - continuations of the crura
Corpus spongiosum - continuation of bulb of penis, contains distal part of spongy urethra
What are the fascial layers of the penis?
Prepuce
Suspensory ligament of penis
Fundiform ligament of penis
Superficial penile fascia
Deep penila fascia
Tunica albuginea
What arteries supply blood to the penis?
Artery of bulb
Deep arteries of the penis
Dorsal artery of the penis
Deep dorsal vein of penis
Superficial dorsal vein of penis
What is the nervous control of an erection?
Parasympathetics - cause relaxation of smooth muscle in deep arteries to allow blood flow
Pudendal nerve - innervates bulbospongiosus and ischiocavernosus muscles
What is the control of emission?
Sympathetics - cause contraction of smooth muscle of urethra to expel semen
What is the control of ejaculation?
Pudendal nerve - causes rhythmic contraction of bulbospongiosus to compress spongy urethra to aid in expulsion
What does an erection cease?
Sympathetics cause constriction of smooth muscles of arteries, ending the erection
Pudendal nerve stimulation ceases
What is an epiostomy?
Tearing of perineal body during childbirth
Can be performed surgically with subsequent repair to prevent tearing and prolapse
