Atlas of Human Anatomy by Netter

Vascular supply from branches/tributaries of SMA/SMV
Left colic artery and vein
Right colic artery and vein
Middle colic artery and vein
Lymphatic drainage to middle colic nodes
Nerve supply
Superior mesenteric plexus along right and middle colic arteries
Inferior mesenteric plexus along left colic arteries
Descending colon
On left side of posterior abdominal wall
Extends from splenic flexure to sigmoid colon
Is secondarily retroperitoneal
May have a short mesentery in one third of people
Vascular supply from branches/tributaries of IMA/IMV
Left colic artery and vein
Superior sigmoid artery and vein
Lymphatic drainage to the epicolic and paracolic nodes
Innervation
Sympathetic fibers from the lumbar sympathetic trunk and superior hypogastric plexus
Parasympathetic fibers from the pelvic splanchnic nerves
Sigmoid colon
S-shaped loop of variable length
Links descending colon with rectum
Long mesentery with a V-shaped root: sigmoid mesocolon
Vascular supply from branches/tributaries of inferior mesenteric artery (IMA)/inferior mesenteric vein (IMV)
Left colic artery and vein
Superior sigmoid artery and vein
Lymphatic drainage to the epicolic and paracolic nodes
Innervation
Sympathetic fibers from the lumbar sympathetic trunk and superior hypogastric plexus
Parasympathetic fibers from the pelvic splanchnic nerves
Rectum and anal canal (Section 5-9: Pelvis and Perineum-Rectum and Anal Canal)
Rectum
Begins anterior to the body of the S3 vertebra
Is approximately 15 cm long
Connects sigmoid colon and anal canal
Fixed, and continuous with the anal canal
Anal canal
Begins at distal end of rectal ampulla
Extends from pelvic diaphragm to anus