Gastrointestinal: Clinical anatomy of Faecal Continence - the Distal GI tract Flashcards
where are faeces stored?
rectum
where is the rectum located?
lies between the pelvic inlet and pelvic floor
when does the sigmoid colon become the rectum?
anterior to s3
- the rectosigmoid junction
when does the rectum become the anal canal?
tip of the coccyx
what lies immediately superior to the elevator ani muscle?
rectum ampulla
what formed most of the pelvic diaphragm?
Levator Ani Muscle
what type of muscle is the Levator Ani Muscle made out of?
skeletal
what is the function of the Levator Ani Muscle?
provides support for the pelvic organs - tonically contracted most of the time
THIS MUST BE RELAXED TO ALLOW DEFECATION
what supplies the Levator Ani Muscle?
nerve to levator ani (branch of the sacral plexus)
Pudendal (S2,3,4)
what happens when the puborectalis contracts?
decreases the anorectal angle
how many sphincters does the anal canal have?
2 [internal and external]
what type of muscle is the internal anal sphincter?
smooth muscle
what stimulates the contraction of the internal anal sphincter?
sympathetic nerves [sphincter is closed]
T12-L2
what type of muscle is the external anal sphincter?
skeletal muscle
what stimulates the contraction of the external anal sphincter?
pudendal nerve
what marks the junction between the part of the embryo which formed the GI tract (endoderm) and the part that formed the skin (ectoderm)?
Pectinate line
what is the arterial supply above the pectinate line?
inferior mesenteric artery
what is the venous drainage above the pectinate line?
portal venous system
what is the lymphatic drainage above the pectinate line?
inferior mesenteric nodes (internal iliac nodes)
what is the arterial supply below the pectinate line?
internal iliac artery
what is the venous drainage below the pectinate line?
to systemic venous system (internal iliac)
what is the lymphatic drainage below the pectinate line?
superficial inguinal nodes
what drains inferior pelvic structures? (lymph)
internal iliac
what drains lower limb, and more superior pelvic structures? (lymph)
external iliac
what drains lymph from the external and internal iliac?
common iliac
where does lymph from the common iliac drain to?
lumbar nodes
what supplies (arterial) the hind gut organs?
inferior mesenteric artery
what causes rectal varices?
portal hypertension
what lies on the right and left of the anal canal?
ischioanal fossae
