This chapter outlines the anatomy, epithelium, vasculature, musculature, and innervation of the rectum and anal canal. The rectum extends from the sacrum to the upper edge of the puborectalis muscle attachment, harboring mucus-secreting columnar epithelium. The (surgical) anal canal, 4–5 cm long, is defined as the tubular part extending from the upper edge of the puborectalis muscle attachment to the anal verge and comprises transitional epithelium, anal epithelium, and stratified squamous epithelium to the boundary of anal skin. Muscular components, including the levator ani muscles, conjoined longitudinal muscle, and internal/external sphincters, support fecal continence and defecation. Arterial supply derives from superior, middle, and inferior rectal arteries, whereas venous plexuses drain into the portal and systemic systems. Neural regulation involves sympathetic and parasympathetic fibers from splanchnic and pelvic nerves, as well as somatic innervation via the pudendal and levator ani nerves, facilitating coordinated motor and sensory control. These structures mutually contribute to the functional and surgical relevance of anorectal anatomy.