WEEK 9 PELVIS AND PERINEUM FINISHED Flashcards
What is the perineum?
Refers to an external surface area as well as a compartment of the body.
The region overlying the inferior pelvis outlet.
It is separate from the pelvic cavity by the pelvic diaphragm.
It is the saddle area, a diamond shaped area when the body is lying down and the legs are abducted
What is the mons pubis?
A bit of fat which is found in front of the pubic symphysis. Protective role, more prominent in women. Helps to protect that area from pressure during intercourse
Where is the mons pubis in relation to the perineum?
Anteriorly
What is lateral to the perineum?
Legs
What is posterior to the perineum?
Gluteal folds and intergluteal cleft
What does mons mean?
Rounded eminence
What is the boundaries of the perineum? Anteriorly Posteriorly Laterally Anterolaterally Posterolaterally
Anteriorly - pubis symphysis Posteriorly - coccyx Laterally - ischial tuberosities Anterolaterally - inferior pubic rami Posterolaterally - Sacrotuberous ligaments
What is the perineal body
The midpoint line between the 2 ischial tuberosities.
A collection of tissue made up of both skeletal and smooth muscle and also different fibres collagen and elastin. Size and consistency varies and is just under the skin. It acts as an anchor and many structures attach to it.
Where is the perineal body in males and female?
Posterior to the bulb of the penis, of the vestibule of the vagina.
What does vestibule mean?
Opening
What muscles attach to the perineal body?
Bulbospongiosum
External anal sphincter
What is the perineal membrane?
A tough sheet of deep fascia that runs between the pubic arch and covers the anterior aspect of the pelvic outlet.
What is the anal canal?
Terminal part of the bowel (2.3-3.5 cm long)
The anus is at the end of the anal canal.
Begins where the pubo recitals muscle forms a sling around the end of the rectum (anorectal junction)
Runs between the upper aspect of the pelvic diaphragm to the anus.
What does anal mean?
Ring
What direction does the anal canal run in?
Inferiorly and posteriorly.
Where does the anal canal run in relation to the perineal body?
Between the perineal body and the anococcygeal ligament.
What are the 2 triangles in the perineum?
Anterior triangle is the urogenital triangle
Posterior triangle is the anal triangle
poos ft Joshuopathy
yep
What is the external anal sphincter?
Large band of voluntary muscle.
Found either side of the inferior 2/3 of the anal canal
Blends superiorly with puborectalis.
Supplied by S4 inferior rectal nerve
What is the internal anal sphincter?
Involuntary band of muscle that surrounds the superior 2/3 of the anal canal.
It is a thickening of the muscle within the bowel and is supplied by the PNS through the pelvic splanchnic nerves.
The muscle direction is both circular and longitudinal
What are anal columns? What do they consist of? What do they contain? What happens at the inferior ends?
Longitudinal ridges in the superior half of the mucous membranes of the anal canal.
They consist of layers of mucous membrane
Contain the terminal branches of the superior rectal artery and vein.
In the inferior ends, the columns are joined by anal valves.
What is superior to the anal valves?
Sinuses which when compressed release mucous which aids in defecation.
What is the pectinate line? What does it mean in terms of embryonic development?
The irregular line produces by the anal valves.
Above the line is endoderm, below the line is ectoderm.
What does the pectinate line divide the anus into? Why is it relevant?
Into superior and inferior regions, the different regions are derived from different embryonic tissue?
What is the arterial supply of the anal canal superior to the pectinate line? what does it drain into?
The superior rectal artery. Drains into the portal venous system (goes through the liver to get to the IVC)
What is the arterial supply of the anal canal inferior to the pectinate line? what does it drain into?
The inferior rectal artery. Drains to the Caval system straight into inferior vena cava.
What is the innervation of the anal canal superior to the pectinate line?
Autonomic (inferior hypogastric plexus)
What is the innervation of the anal canal inferior to the pectinate line?
Somatic (pudendal nerve S2-S4)
