Male pelvic contents and anal triangle Flashcards
What is the blood supply to the rectum?
- Superior rectal (from inferior mesenteric)
- Middle rectal (from internal iliac)
- Inferior rectal (from internal pudendal)
Which muscle aids the external anal sphincter in the control of defecation?
The Puborectalis
Bends the rectum to slow the passage of faeces and helps maintain continence
What is the main component of the ischioanal fossae and what is the importance of this?
Adipose tissue/fat
Supports the neurovascular structures
Allows the anal canal space in which it can expand into during the expulsion of faeces from the body
True or False?
Both of the anal sphincters are under voluntary control
False!
The internal anal sphincter is formed by the wall of the anal canal and is under involuntary control
The skeletal muscle that surrounds the opening of the anal canal forms the external anal sphincter which is under voluntary control
When does the rectum become the anal canal?
When it pierces the pelvic floor in the anal triangle
What is the role of the prostate gland?
Releases fluid that increases the liquid component of semen and helps support the sperm
The fluid is alkaline so helps to neutralise the acidic environment of the vagina
Why might hypertrophy of the prostate gland cause urinary problems?
Enlargement of the gland can affect the passage of urine from the bladder - patients may experience leakage of urine or the desire to urinate
If lobes increase in size they can compress or distort the urethra which can cause problems releasing urine
Can lead to the formation of pouches in the bladder that urine can pool in, increasing the likelihood of UTIs
What is highlighted in the image?
Ischioanal fossae
What arteries supply the prostate?
Internal pudendal
Middle rectal
Inferior vesical arteries
What is the relationship of the internal rectal plexus and the internal anal sphincter?
The plexus sits superficial to the internal anal sphincter
Describe the journey of the vas deferens towards the pelvis
Cross the lateral wall of the pelvis over the external iliac vessels to descend towards the seminal vesicles
What is highlighted in this image?
Seminal vesicle
What nerve controls external anal sphincter?
Pudendal nerve (S2-4) - inferior rectal branch
What does this image show?
Anal columns
What makes up the borders of the ischioanal fossae?
Walls- ischial tuberosity, rectum/anal canal
Roof- levator ani muscle
Floor- skin
What is the innervation of the external anal sphincter?
The inferior rectal nerve - a branch of the pudendal nerve
What is the name of the spaces found on either side of the rectum?
The ischioanal (ischiorectal) fossae
Which structures does the external anal sphincter pass between to wrap around the opening of the anal canal?
Anococcygeal ligament Perineal body (a dense structure of connective tissue that lies at the edge of the urogenital diaphragm to provide attachment to the muscles of the perineum)
What is highlighted by this image?
The Pectinate line
What is the clinical importance of the prostatic venous plexus?
Has many communications with the vertebral veins which can permit metastasis of prostatic cancers to the lower vertebral column
What is the anal triangle?
An area found in both males and females
Found between an imaginary line between the ischial tuberosities and the coccyx
What does the seminal vesicle do?
Secretes fluid to make the ejaculate more fluid as it passes into the urethra
Support the sperm - for example releases fructose to provide the sperm with energy
How many lobes does the prostate gland have?
5 incomplete lobes
What is the relationship of the prostate gland to the bladder?
The prostate sits inferior to the bladder
What is the lymphatic drainage of the testes?
Drain to aortic nodes at the root of the testicular artery at L2- follows its arterial supply
What structure is highlighted?
Internal anal sphincter
What is the blood supply to the distal aspect of the vas deferens and the seminal vesicles?
Branches of the anterior division of the internal iliac artery - the inferior vesical and prostatic artery (a branch of the inferior vesical artery)
What structure is highlighted?
External anal sphincter
How is the ejaculatory duct formed?
The vas and seminal vesicle join and form the ejaculatory duct
What is the contents of the ischioanal fossae?
Branches of the pudendal nerve, artery and vein
Adipose tissue
What is the blood supply to the inferior rectum and anal canal?
Inferior rectal artery - a branch of the internal pudendal artery
Describe the appearance of the seminal vesicles
Highly coiled tubes of around 5cm long (stretched out would be 10-15cm long)
Appear lumpy and small and sit posterior to the bladder
Wrapped in connective tissue
What are the small internal folds of the anal canal?
Anal columns
How is the prostatic gland supported?
By the puboprostatic ligament and the pelvic floor muscles
Pubococcygeus forms a muscular support for the prostate gland called puboprostaticus/ levatore prostatae
How does the vascular supply and drainage change at the pectinate line?
Arterial is from the inferior mesenteric artery above the line and below it is from the internal iliac
Venous drainage above the line is to the portal venous system and below it goes to the caval venous system
What are the divisions of the external anal sphincter?
Divided by connective tissue into deep, superficial and subcutaneous parts
What is the role of the vas deferens?
Transports sperm from the testis to the ejaculator duct and into the urethra
Which structure passes closely with the perineal nerve?
Internal pudendal artery
What structure is highlighted?
The Vas Deferens
How does innervation change above and below the pectinate line?
Above - Visceral motor and sensory innervation
Below - Somatic motor and sensory innervation
What is the blood supply to the wall of the anal canal?
The inferior rectal arteries
What is the lymphatic drainage of the rectum/anal canal in relation to the pectinate line?
Above - drainage is to internal iliac lymph nodes
Below - drainage to superficial inguinal lymph nodes
What is the importance of the pectinate line?
Marks the end of the visceral (internal) part of the digestive tract and the start of the parietal (body wall) structures
What is contained within the anal columns?
Terminal branches of the superior rectal vessels
What is the location of the seminal vesicles in relation to the bladder?
Sit posterior to the bladder
Describe the journey of the ureters in the male to the pelvis
Ureter passes from the abdomen and into the pelvis
Crosses the bifurcation of the common iliac vessels before descending towards the base of the bladder
What structure is highlighted?
The prostate gland
What structures pass through the prostate?
Prostate receives the ejaculatory ducts and also has the urethra passing through it
What is the lymphatic drainage of the skin of the penis and wall of the scrotum?
Drains to superficial inguinal nodes
