Male pelvis part 2 Flashcards
What are the ischio-anal fossae
The ischioanal fossae are fat-filled spaces in the anal triangle. They allow recto-anal and vaginal expansion. In their lateral wall is the pudendal neuro-vascular bundle supplying the perineum including the lower rectum.
Describe the formation of the ischio-anal fossae
Because the levator ani muscles course medially from their origin on the lateral pelvic walls, above, to the anal aperture and the urogenital hiatus below, inverted wedge-shaped gutters occur between the levator ani muscles and adjacent pelvic walls as the two strucutres diverge inferiorly
In the anal triangle, these gutters on each side of the anal aperture are termed ischio-anal fossae
Describe the structure of the ischio-anal fossae
lateral walls- iscium, obturator internus and sacrotuberous ligament
medial wall- levator ani muscle
the medial and lateral walls converge superiorly where the levator ani attaches to the fascia covering the obturator internus- the ischio-anal fossae allow movement of the pelvic diaphragm and expansion of the anal canal during defcation
Describe the anterior recesses of the ischio-anal fossae
ischio-anal fossae are continuous anteriorly with recesses that project into the urogenital triangle superior to the deep perineal pouch
shaped like 3-sided pyramids that have been tilted on their sides
apex- closed and points towards the pubis
base open- continuous posteriorly with its related ischio-anal fossae
inferior wall- deep perineal pouch
superomedial wall- levator ani muscle and the superlateral wall is mainly by the obturator internus
the ischio-anal fossae and their recesses are often filled with fat
Describe abscesses in the ischio-anal fossae
The anal mucosae is vulnerable to injury and may easily be torn by hard faeces
Occasionally, patients develop inflammation and infection of the anal canal (sinuses or crypts)- the infection can spread between the sphincters, producing intrasphinteric fistulas- the infection can tract superiorly to the pelvic cavity or laterally to the ischio-anal fossae
Care must be taken when draining abscesses as damage to the innervation of the anal sphincters will result in faecal incontinence
What is the ductus deferens
Long muscular duct that transports spermatozoa from the tail of the epididymis in the scrotum to the ejaculatory duct in the pelvic cavity
Describe the passage of the ducts deferens
leaves the lower end of the epididymis to ascend in the spermatic cord and passes through the inguinal canal into the anterior abdominal wall
after passing through the deep inguinal ring, the ductus deferens turns medially around the lateral side of the inferior epigastric and crosses the external iliac artery and vein at the pelvic inlet to enter the pelvic cavit
the duct descends medially on the pelvic wall, deep to the peritoneum and crosses the ureter superficially (posteriorly to the bladder too) to reach the posterior of the prostate
here it dilates, forming the ampulla, before joining the duct of the seminal vesicle to form the ejaculatory duct that enters the prostatic part of the urethra
What is a vasectomy
Due to thick smooth muscle wall it is easily palpable between the superficial inguinal ring and testes- and because it can be accessed between the skin and superficial fascia it is amenable to surgical dissection and division
this is carried out bilaterally and the patient is rendered sterile
What is meant by the spermatic cord
the collective name for the deferns, the testicular and other vessels and nerves and various connective tissue and muscular (cremaster) coverings derived from the abdominal musculature that form the inguinal canal- it therefore only lies between the superficial inguinal ring and the testis
List the contents of the spermatic cord
ductus deferns
artery to the ductus deferens from the inferior vesical artery
testicular artery (from abdominal aorta)
the pampiniform plexus of veins
the cremasteric artery and vein (small vessels associated with cremasteric fascia)
genital branch of the genitofemoral nerve (innervation to the cremasteric muscle)
sympathetic and parasympathetic nerve fibres
lymphatic
remnants of processus vaginalis
Describe the formation of fascial coverings of the spermatic cord
These structures enter the deep inguinal ring, proceed down the inguinal canal and exit from the superficial inguinal ring having acquired 3 fascial coverings along their journey- this collection of structures and fascia continues into the scrotum where the structures connect with the testes and fascia surrounding the testes
What are the three fascial coverings of the spermatic cord
internal spermatic fascia (deepest and arises from the transversalis fascia and is attached to the margins of the deep inguinal ring)
cremasteric fascia with the associated cremasteric muscle- middle fascial layer- arises from the internal oblique
external spermatic- most superficial covering, arises from the aponeurosis of the external oblique and is attached to the margins of the superficial inguinal ring
Summarise the testes
Ellipsoid-shaped and enclosed within the end of an elongated musculofacial pouch, which is continuous with the anterior abdominal wall and projects into the scrotum. The spermatic cord is the tube-shaped connection between the pouch in the scrotum and the abdominal wall.
Describe the structure of the testes
The testes are paired gonads
each is encapsulated in a thick capsule called the tunica albuginea. Lobules of seminiferous tubules are lined with the germinal epithelium that gives rise to spermatozoa
the spermatozoa drain into the rete testes (straight tubules) and via the efferent ductules into the epididymis, where maturation continues (gain ability to move and fertilise egg) until they are ready to be secreted.
the ductus deferens conveys the sperm to the seminal vesicles, where they join the seminal vesicle ducts to form the ejaculatory ducts, which empty into the prostatic urethra
What are the testes surrounded by
Surrounded by tunica vaginalis (with parietal and visceral layer)
Describe the epididymis
Couse along the posterolateral side of the testes
efferent ductules- form an enlarged coiled mass that sits on the posterior superior pole of the testes and forms the head of the epidymis
true epididymis- single long coiled duct into which the efferent ductules all drain, and which continues inferiorly along the posterolateral margin of the testis as the body of the epididiymis and enlarges to form the tail of the epidymis at the inferior pole of the testes
Describe the venous drainage of the testicles
right- IVC
left- left renal vein
Describe the lymphatic drainage of the testes
Into the lateral aortic or lumbar noes and pre-aortic nodes in the abdomen- not palpable- why testicular cancer has a poor diagnosis
Summarise the erectile tissues in males
The crura (legs) of the corpora cavernosae attach to the ischiopubic rami.
The urethra traverses the length of the corpus spongiosum.
Catheters can get caught in the navicular fossa (fossa terminalis).
Testicular cancers are heterogenous neoplasms
Outline the vasculature to the penis
Main supply: Internal pudendal artery from internal iliac
Deep artery – supplies corpora cavernosa
Dorsal artery – supplies the skin and connective tissue
Artery of the bulb – bulb, corpus spongiosum, glans and urethra.
Branches supplying the cavernous spaces are usually coiled – helicine arteries
What is the effect of PSNS stimulation of the penile vasculature
Parasympathetic stimulation causes helicine arteries to relax allowing blood flow
Summarise the nerves of the pelvis
Pelvic contents supplied by autonomic nerves only
Sympathetic from lower thoracic and upper lumbar (T10 - L2) segments via hypogastric plexus
Parasympathetic from S2-4 outflow
Pelvic sensation is visceral and poorly localised - pain is referred to suprapubic region and perineum
Describe the parasympathetic outflow from S2-S4
The parasympathetic out flow from S2-S4 joins the inferior hypogastric plexus.
Describe the Somatic: Pudendal nerve from S2 - S4
function
Sensory - Dorsal nerve of penis –sensory to penile skin, glans
Motor – to perineal muscles bulbospongiosus and ischicavernosus -causing ejaculation + external urethral sphincter
Describe the PSNS function from S2-S4
Vasodilation of arterioles in erectile tissue (male & female)
Secretion in prostate, bulbourethral glands
Describe SNS function from S2-S4
Contraction of smooth muscles of epididymis, vas deferens, seminal vesicles, prostate causing emission.
Contraction of internal urethral sphincter (in males) to prevent reflux of semen
Summarise the nerves of the perineum
Somatic nerves, mainly from sacral segments
Most important nerve is pudendal (S2-4)
Supplies all perineal skeletal muscles
Sensory to penis, lower urethra, lower rectum and anal canal
Describe the lumbosacral plexus
Somatic nerves leave the pelvis from the lumbosacral plexus:
The main supply to the perineum is from the pudendal nerve S2-S4
Describe the passage of the pudendal nerve
The nerve originates from the sacral plexus and leaves the pelvic cavity through the greater sciatic foramen inferior to the piriformis muscle, passes around the sacrospinous ligament and then enters the anal triangle of the perineum, passing inferiorly through the lesser sciatic foramen
As It enters and courses through the perineum, it travels along the lateral wall of the ischio-anal fossa in the pudendal canal, which is a tubular compartment formed in the fascia that covers the obturator internus muscle- the canal also contains the internal pudenal artery and veins
The pudendal nerve has 3 major branches (inferior rectal, perineal nerves and dorsal nerves of the penis or clitoris- these branches follw branches of the accompanying internal pudendal artery
What does the pudendal nerve innervate
Muscles of perineum and pelvic floor:
ischiocavernous
bulbospongiosus
levator ani muscles
anterior perineum, penis/clitoris and scrotum/vulva.
What does the inferior rectal branch innervate
anal sphincter, levator ani m.)
What does the perineal branch innervate
skeletal branches in the superficial and deep perineal pouches
sensory to scrotum and labia
What does the dorsal branch of penis and clitoris innerbate
Sensory to the penis and clitoris, particularly the glans
Describe erection
Central parasympathetic pathway activated by psychic stimulation.
Pudendal artery/arterioles relax and allow blood flow into cavernous spaces of erectice tissue (male & female).
Describe secretion
Stimulation of para-sympathetic ganglia on prostate, seminal vesicles, and other glands (in females)
Describe emission
Central sympathetic pathway activated and smooth muscle contraction of vasdeferens, prostate, seminal vesicles.
Internal urethral sphincter (male) contracts. Bladder muscle contraction is prevented by sympathetic inhibitory action (no urine flow)
Describe ejaculation
Entry of semen into urethra triggers somatic reflex (via pudendal nerve) causing contraction of bulbospongiosus muscle (skeletal).
Describe detumescence
Selected sympathetic nerves supplying pudendal arterioles are activated causing arteriolar constriction to restrict blood supply to cavernous spaces
Describe testicular torsion
caused by twisted spermatic cord leading to ischaemia of the testes
medical emergency- immediate surgery required
red, hot, swollen testes occurring high in the scrotum
occurring mostly in young boys, usually after birth and during puberty
defect in arterial supply, causing cremasteric muscle spasm to twist the spermatic cord and occlude the artery - very painful
Describe variocele
abnormal enlargement and dilatation of the pamphiform plexus
caused by defective valves or compression of a nearby structure
painless
described as feeling like a bag of worms
Varicocele is usually benign in terms of reproductive impact. Left vein is also more perpendicular = more chance of varicocele.
Describe hydrocele
Accumulation of fluid around a testicle
often caused by fluid secreted from a remnant piece of peritoneum wrapped around the testicle, called the tunica vaginalis- patent processus vaginalis
often resolves spontaneously
Describe continence
Continence is the ability to control movements of the bowels and bladder. Exercising pelvic floor muscles improves symptoms
Pelvic diaphragm has 2 roles:
Physically acts as floor of abdomen
Constrict urethra, vaginal and anus
Stress incontinence = urination (or defecation) during coughing, sneezing or exercise (more common in women
Describe prolapse
Pelvic organ prolapse = pelvic organ drops down or presses into or the vagina.
Caused by weakening of the pelvic diaphragm muscles or connecting tissues.
Can occur during pregnancy too
Describe episiotomy
Surgical incision of the perineum and the posterior vaginal wall.
Vaginal tears can occur during childbirth. Episiotomy prevents against soft-tissue tearing which may involve the anal sphincter and rectum.
Why may you need an episiotomy
Vaginal tears can occur during childbirth, most often at the vaginal opening as the baby’s head passes through, especially if the baby descends quickly. Episiotomy is done in an effort to prevent against soft-tissue tearing which may involve the anal sphincter and rectum. Its routine use is no longer recommended. Having an episiotomy may increase perineal pain during postpartum recovery, resulting in trouble defecating, particularly in midline episiotomies In addition, it may complicate sexual intercourse by making it painful and replacing erectile tissues in the vulva with scar tissue.
Describe abscesses and fistulas
The anal mucosa can become torn following defecation which can lead to infection and accumulation of inflammatory exudation/debris = abscess (pus).
If the abscess is deep enough to pass into another hollow organ (creating a passage) it forms a fistula.
Describe pudendal nerve block
Palpate the ischial spine transvaginally using the middle finger
Relax your index finger to the side of the middle finger
Using your other hand, run the syringe along the midline between your index and middle finger
Reasons for administration:
Natural childbirth
Episiotomy
Must avoid pudendal artery to avoid systemic circulation.
Describe the passage of ureters in males
enters the pelvis by crossing the external iliac vessels and then running inferiorly down the posterior aspect of the lateral wall anterior to the internal iliac vessels
it then turns forwards at the ischial spine on the superior aspect of the pelvic floor
here the ureter is crossed by the vas deferens
no sphincter as it passes through the bladder wall- obliquity of passage enures that as the bladder is filled- the urethra is effectively closed
Describe catheterisation in males
spongy urethtra- surrounded by erectile tissue of the bulb of the penis immediately deep to the deep perineal pouch, the wall of this segment is relatively thin and angles superiorly to pass through the deep perineal pouch- at this position the urethra is vulnerable to damage
membranous part- runs superiorly as it passes through the deep perineal pouch
prostatic part- slight concave curve anteriorly as it passes through the prostate
Describe the complications of catheterisation in males
Urinary catheterization- process of inserting tube through urethra + into bladder
Indications: urine output monitoring or when patient unable to pass urine
Catheterization more complex in males, 2 angles: infrapubic (1st bend) + Prepubic (2nd bend)
The tip of a urethral catheter can also become lodged in the prostatic utricle
A urinary catheter, must negotiate a 900 bend in the urethra as it passes from the perineum to the pelvis.
What is the consequence of the bladder filling with urine
As the bladder fills with urine, it rises above the level of the pubic symphysis behind the lower part of the abdominal wall, pushing the peritoneum away from the anterior abdominal wall as it rises
it then becomes possible to insert a needle or drainage tube into the bladder just superior (2cm) to the pubic symphysis without entering the peritoneal cavity and damaging any structures
