5. Pelvis and Perineum: Male Flashcards
Differences between the male pelvis and the female pelvis (pelvic inlet, sub-pubic angle, ratio of distance between pubic symphysis and anterior margin of the acetabulum : diameter of acetabulum, true pelvis, false pelvis)
Pelvic inlet: F= oval/ round. M= heart shaped/ narrow Ischial spines: F= DONT point medially, M= project medially Sub-pubic angle: F= > 80 degrees M= 50-60 degrees PS-A : A- F= 1 or > 1 M= < 1. True pelvis: F= Shallow, wide and cylindrical, M= deep, narrow and tapers False pelvis: F= wide, M it is narrow
Describe the orientation of the pelvic girdle with reference to 2 bony landmarks that are in the same plane.
ASIS and pubic tubercle are in the same vertical plane
True or False: the parietal peritoneum reaches the pelvic floor.
False: the parietal peritoneum continues into pelvic cavity but does NOT reach the pelvic floor
What is found in the space between parietal peritoneum and pelvic wall that is not occupied by viscera?
Pelvic fascia
What are the ligaments that support pelvic viscera made up of?
Pelvic fascial condensations
Describe the path of the ductus deferens from the epididymis to the urethra.
Ductus deferens goes in through the superficial inguinal ring, through the inguinal canal and out of the deep inguinal ring.
Then goes superior to the bladder, crosses the ureter and goes posterior to the ureter and joins the urethra through the prostate.
Before joining the urethra, the ductus deferens joins with the seminal vesicle to form the ejaculatory duct which then joins the urethra in the prostate.
Which pelvic viscera are completely covered by peritoneum?
Uterine tubes
What 2 structures can be felt in a DRE of a healthy man?
Prostate
Seminal vesicles.
Where do seminal vesicles open into the ductus deferens? What does this joining form and where does it open into?
Between the ampulla and ejaculatory duct.
Forms the ejaculatory duct, opens into prostatic urethra
What glands are found within the urogenital diaphragm and where do these glands open into?
Bulbourethral Glands
(produce secretions that lubricate the urethra)
Open into the urethra deep to the perineal membrane
What is the semen composed of?
60%: Secretions of the ductus deferens and seminal vesicles
40% prostatic secretions
What is the cul-de-sac in the prostatic urethra is a site where a catheter could get lodged?
Prostatic utricle
Describe the internal urethral sphincter.
Smooth muscle
Well organised in males (not organised in females)
Under sympathetic control (closes during ejaculation)
State 3 areas of narrowing of the urethra for the navigation of a catheter.
External urethral orifice (narrowest part)
90 degree turning of the urethra in the membranous part
Prostatic utricle
What large blood vessel is involved in supplying the pelvis and its contents? What are the 2 main branches of this vessel?
Internal iliac artery
Anterior and posterior branches
Where do the testes receive their blood supply from?
Testicular arteries: arising from the abdominal aorta
What are the borders/apices of the perineum?
Pubic Symphysis
Ischial Tuberosities
Coccyx
What can the perineum be divided into?
Anterior: urogenital triangle
Posterior: anal triangle
What are the fat-filled spaces that separate the anal canal and the levator ani from the pelvic walls?
Ischioanal Fossae
How can the anterior triangle be further divided?
Divided into SUPERFICIAL and DEEP POUCHES by the PERINEAL MEMBRANE
What is the perineal membrane?
Thick triangular fascial structure attached to the pubic arch and extending between the ischiopubic rami.
Posteriorly free margin
What are the 2 potential spaces related to the perineal membrane? Where are they?
Superficial: below PM and above perineal fascia
Deep: above PM and below fascia of pelvic diaphragm
What regions of erectile tissue that make up the penis?
Corpora cavernosae (paired muscles) Corpus spongiosus
(Erectile tissue within the perineum is surrounded by skeletal muscles, but not under voluntary control)
What muscle is associated with the corpus cavernosum? Where does it attach?
Ischiocavernosus
Attaches to the ischiopubic ramus
What muscle is associated with the bulb of the penis/corpus spongiosum?
Bulbospongiosus
This is midline and attached to the perineal membrane
How is the bulbospongiosus different in females?
The bulb divides around the vestibule to form the vestibular bulbs
What are the 2 ligaments of the penis and where are they attached?
Suspensory ligament
Fundiform ligament
Attached to the pubic symphysis
Where does the rectum receive arteries from?
1 pair of arteries from the inferior mesenteric (superior rectal artery)
2 pairs from the internal iliac artery (middle and inferior rectal arteries)
Venous drainage is similar
What is the role of the ischio-anal fossae?
Allows recto-anal and vaginal expansion.
Where is the pudendal neurovascular bundle found?
In the lateral border of the ischio-anal fossa.
Which mass of erectile tissue does the urethra travel through?
Corpus Spongiosum
Describe the passage of sperm from the seminiferous tubules to the urethra
Seminiferous tubules Epididymis Vas deferens Spermatic cord runs through superficial then deep inguinal ring Joins ducts of seminal vesicles Becomes ejaculatory duct Opens into prostatic part of urethra
Describe the layers of the spermatic cord
External spermatic fascia (ext. oblique aponeurosis)
Cremasteric fascia (Int. oblique muscle)
Internal spermatic fascia (trasversali fascia)
Testicular artery and pampiniform plexus of veins
Describe venous drainage of the testes
Right: Drains into IVC
Left: Drains into left renal vein (then IVC)
Which erectile tissue is paired?
Corpus cavernosum
Where do the “legs” of the corpora cavernosae attach?
Ischiopubic rami
Where in the tip of the penis can catheters get caught?
Navicular fossa
Fossa terminalis
What is the main branch of the internal iliac artery that supplies the penis?
Internal pudendal artery
Which artery supplies the corpora cavernosae?
Deep artery
What artery supplies the skin and connective tissue?
Dorsal artery
Describe the branches supplying cavernous spaces
Helicine arteries (coiled)
What does parasympathetic stimulation do to helicine arteries?
Causes relaxation
Allows blood flow
What nerves supply the pelvic contents? Where do the sympathetic and parasympathetic nerves arise from?
AUTONOMIC NERVES
Sympathetic: lower thoracic and upper lumbar (T10-L2) via the hypogastric plexus
Parasympathetic: S2-S4
Where is pelvic sensation referred to?
Suprapubic region
Perineum
What does the pudendal nerve provide sensory innervation to and which smaller branch of the pudendal nerve is involved in this?
Penile skin and glans
via the dorsal nerve of the penis
What does the pudendal nerve provide motor innervation to?
Perineal muscles (bulbospongiosus and ischiocavernosu)
Leads to ejaculation
External urethral sphincter
What are the effects of parasympathetic nerves in the pelvis?
Vasodilation of arterioles in erectile tissue leading to erection.
Secretion in prostate and bulbourethral glands
What are the effects of sympathetic nerves in the pelvis?
Contraction of smooth muscles in epididymis, vas deferens, seminal vesicles, prostate during ejaculation
Contraction of internal urethral sphincter (prevents reflux of semen)
What does the pudendal nerve supply?
All perineal skeletal muscles
Which plexus do the somatic nerves leave the pelvis from?
Lumbosacral plexus
Which arteries relax to allow blood flow into the penis?
Internal pudendal artery
