Perineum and its pouches Flashcards
Boundaries of the perineum
Anteriorly - pubic symphysis
Anterolaterally- inferior pubic and ischial rami
Laterally- Ischial tuberosities
Posterolaterally- Sacrotuberous ligaments
POSteriorly- Inferiormost sacrum and coccyx
What are the two triangles of the perineum and what divides them
Transverse line joining anterior ends of ischial tuberosities divides perineum into:
- ANal triangle
- Urogenital triangle
What is the superficial perineal pouch
A potential space between the membranous layer of subcutaneous tissue and the perineal membrane bounded laterally by ischiopubic rami
What doe the superficial perineal pouch contain in males
Root of penis and ischiocavernosus and bulbospongiosus
Proximal part of the spongy urethra
Superficial transverse perineal muscles
Deep perineal branches of the internal pudendal vessels and pudendal nerves
What does the superficial perineal pouch contain in females
Clitoris and ischiocavernosus
Bulbs of the vestibule and surrounding muscle (bulbospongiosus)
Greater vestibular glands
Deep perineal branches of the internal pudendal vessels and pudendal nerves
Superficial transverse perineal muscles
Boundaries of the ischioanal fossa
Laterally- ischium and inferior part of obturator internus
Medially- anal sphincter, with a sloping superior medial wall or roof formed by levator ani
Posteriorly- sacrotuberous ligament and gluteus Maximus
Anteriorly- bodies of the pubic bones
Contents of iscioanal fossa
Perineal branch of S4
Inferior anal/rectal vessels and nerves
Perforating branch of S2 and S3
Structures which run through the pudendal canal
Internal pudendal artery and vein
Pudendal nerve
Nerve to the obturator interns
these all enter the canal at the lesser sciatic notch
What do the internal pudendal vessels supply and drain
Perineum
What does pudendal nerve split into
Inferior anal/rectal nerve
Perineal nerve: muscular (deep) branches and superficial branch
–>Superficial branches divide to form posterior scrotal nerves
Dorsal nerve of penis
What are the primary sensory nerves serving the male or female organ
Dorsal nerve of the penis or clitoris
What does the ductus deferens enlarge to form before its termination
Ampulla of ductus deferens
What does the ductus deferens narrow and join the duct of and what does it form
Duct of seminal gland to form the ejaculatory gland
What does the fibrous capsule of the prostate contain
Prostatic plexuses of nerves and veins
Where is the isthmus of the prostate and where does it lie
lies anterior to the urethra
What are the different lobes of the prostate
Right and left lobe of the prostate:
- Inferoposterior lobule
- Inferolateral lobule
- Superomedial lobule
- Anteromedial lobule
What are prostatic arteries branches of
Internal iliac artery
What do the prostatic veins join to form
Prostatic venous plexus
What is the base of the prostate related to
Closely related to neck of bladder
What is the apex of the prostate in contact with
Fascia on the superior aspect of the urethral sphincter and deep perineal muscles
What is the posterior surface of the prostate related to
Ampulla of the rectum
What are the inferolateral surfaces of the prostate related to
Levator ani
What do the lymph vessels of the prostate drain into
Internal iliac nodes but some pass to the sacral lymph nodes
What is the perineal body
Central tendon of perineum. It is a pyramidal fibromuscular mass in the middle line of the perineum at the junction between the urogenital triangle and the anal triangle
What are the structures related to the perineal body
ISchiocavernosus
Bulbocavernosus
Transverse perineal
Where does the spermatic cord begin and end
Begin- inferior abdomen
End-Scrotum
Where is the spermatic cord formed at
Opening of the inguinal canal (deep inguinal ring)
opening is located lateraly to the inferior epigastric vessels
How does the spermatic cord enter the scrotum
Superficial inguinal ring
What are the contents of the spermatic cord bound together by and where are these derived from
3 fascial layers which are derived from the anterior abdominal wall
What are the fascial layers which bind the contents of the spermatic cord together and what are they derived from
External spermatic fascia
–> derived from deep subcutaneous fascia
Cremaster muscle and fascia
–> derived from the internal oblique muscle and its fascial coverings
Internal spermatic fascia
–>Derived from the transversalis fascia
What is the cremasteric reflex
Stimulated by stroking the superior and medial part of the thigh. Produces an immediate contraction of the cremaster muscle which elevates the testis on the side that has been stimulated
What are the two parts of the cremasteric reflex
Afferent (sensory) limb - ilioinguinal nerve (innervates the skin of the superomedial thigh). fibres from this nerve enter the spinal cord at L1
Efferent (motor) limb -genital branch of the genitofemoral nerve (innervates the cremaster muscle)
Blood vessels in the spermatic cord and what they do
Testicular artery - branch of the aorta that arises just inferiorly to the renal arteries
Cremasteric artery and vein- suppplie the cremasteric fascia and muscle
Artery to the vas deferens- branch of the inferior vesicle artery, which arises from the internal iliac
Pampiniform plexus of testicular veins- drains venous blood from the testes into the testicular vein
Nerves that run I the spermatic cord and what they supply
Genital branch o the genitofemoral nerve- supplies the cremaster muscle
Autonomic nerves
Other structures that run through the spermatic cord and their uses
Vas deferens - the duct that transports sperm from the epididymis to the ampulla (a dilated terminal part of the duct), ready for ejaculation
Processus vaginalis- projection of the peritoneum that forms the pathway of descent for the testes during embryonic development. In the adult, it is fused shut
Lymph vessels- These drain into the para-aortic nodes, located in the lumbar region
What are the three muscle layers of the vas deferens
Inner layer- longitudinal smooth muscle
Intermediate layer- circular smooth muscle
Outer layer-longitudinal smooth muscle
What is testicular torsion
SPermatic cord twists upon itself which can lead to strangulation of the testicular artery (resulting in necrosis of the testis)
What is a common cause of testicular torsion
Spasm of the cemasteric muscle fibres which force the testicle to spin around its own cord
A loose testicle in a large peritoneal sac may facilitate this movement
