Colorectal Flashcards
4 layers of the colon
mucosa–> submucosa –> muscularis propria –> serosa
retorperitoneal components of colon
ascending, descending, and sigmoid are all retroperitonel
peritoneum
covers anterior upper and middle 1/3 of the rectum
muscularis mucosa
circular/longitudinal interwoven inner layer
muscularis propria
circular layer of muscle
plicae semilinaris
transverse bands that from haustra
bands that run longitudinally along the colon
taenia coli
superior mesenteric artery
ascending and 2/3 transverse colon
ileocolic, right and middle colic arteries
inferior mesenteic artery
1/2 transverse colon, descending colon, sigmoid colon, and upper portion of rectum
left colic, sigmoid branches, superior rectal artery
marginal artery
runs along colon margin, connecting SMA to IMA
collateral flow
arc of Riolan
short direct connection between IMA and SMA
venous drainage of the colon
follows arterial supply ,
except IMV –> goes to splenic vein, joins SMV to form portal vein
superior rectal artery
branch of IMA
middle rectal artery
branch of internal iliac
inferior rectal artery
branch of internal pudendal (which is a branch of the internal iliac)
lymphatic drainage from superior and middle rectum
drain to IMA nodal lymphatics
lymphatic drainage from lower rectum
IMA nodes, internal iliac nodes
watershed area of the colon
splenic flexure ( Griffiths point) (SMA and IMA junction) rectum (Sudaks point) superior rectal and inferior rectal artery junction
external sphincter
puborectalis muscle- under CNS control (voluntary)
a continuation of levator ani muscle
nerve supply to the external sphincter
pudendal nerve, perineal branch of S4
internal sphincter
involuntary control
continuation of the circular band of colon muscle (smooth)
transition between anal canal and rectum
levator ani
mucus secreting goblet cells
crypts of lieberkuhn
source of nutrients for colonocytes
short chain fatty acids
stump pouchitis
TX: short chain fatty acids
infectious pouchitis
TX metronidazole
denovilliers fascia
rectovesicular fascia in men
rectovaginal fascia in women
waldeyers fascia
rectosacral fascia