yläperäsuoli

Yläperäsuoli, also known as the upper rectum, refers to the topmost portion of the rectum. Anatomically, the rectum is the final section of the large intestine, terminating at the anus. The division into upper and lower sections is primarily for descriptive purposes and can vary slightly depending on the source or context. The upper rectum is generally considered to be the part that lies above the peritoneal reflection, meaning it is within the peritoneal cavity in its upper aspect, and retroperitoneal in its lower aspect.

This region is crucial for the storage of feces before defecation. Its smooth muscle walls, under involuntary control, also play a role in regulating the passage of waste. The upper rectum receives its blood supply from the superior rectal artery, a continuation of the inferior mesenteric artery. Venous drainage follows a similar pattern, with the superior rectal vein draining into the portal venous system. Lymphatic drainage is to the inferior mesenteric lymph nodes. The nerve supply is derived from the autonomic nervous system, influencing both motility and sensation.

Understanding the anatomy and physiology of the upper rectum is important in clinical medicine, particularly in the diagnosis and treatment of conditions such as rectal cancer, inflammatory bowel disease, and other anorectal disorders. Surgical approaches and the location of tumors within this segment can influence treatment strategies and prognosis.