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From Digestive System
Splenic Flexure
Bend between transverse and descending colon.
Overview
The splenic flexure, also known as the left colic flexure, is a sharp bend in the colon where the transverse colon transitions into the descending colon. It marks a key anatomical and physiological transition point in the large intestine, associated with changes in blood supply and innervation. It is named for its proximity to the spleen.
Location
The splenic flexure is located in the left upper quadrant (LUQ) of the abdomen. More specifically, it:
Lies beneath the spleen, near the tip of the 9th or 10th rib
Is positioned posterior to the stomach and anterior to the left kidney
Marks the junction between the midgut and hindgut embryologically
It is more superior and sharply angled than the right (hepatic) flexure, making it more fixed and less mobile.
Structure
The splenic flexure is structurally a continuation of the colonic wall but has unique anatomical considerations:
Serosal covering: Intraperitoneal, suspended by the phrenicocolic ligament and adjacent to the splenocolic ligament
Wall layers: Mucosa, submucosa, muscularis externa, and serosa—consistent with the rest of the colon
Vascular supply: Dual blood supply from both the superior mesenteric artery (SMA) via the middle colic branch and the inferior mesenteric artery (IMA) via the left colic branch
Lymphatic drainage: Drains into the inferior mesenteric and para-aortic lymph nodes
Function
The splenic flexure contributes to the colon’s overall function of:
Transporting fecal material: Facilitates the transition of intestinal contents from the transverse colon to the descending colon
Absorption: Continues absorption of water, electrolytes, and vitamins produced by colonic bacteria
Fermentation: Supports microbial fermentation of undigested material
Physiological Role(s)
Though not functionally distinct, the splenic flexure plays roles in:
Segmental contraction: Assists in forming and moving feces via haustral and mass movements
Transitional physiology: Reflects a shift in autonomic innervation—from vagus nerve (midgut) to pelvic splanchnic nerves (hindgut)
Vascular watershed area: Located at the border of SMA and IMA territories, making it vulnerable to ischemia
Clinical Significance
The splenic flexure is clinically important for several reasons:
Ischemic colitis: It is a known “watershed area” with reduced collateral circulation, making it susceptible to ischemia during hypoperfusion states
Splenic flexure syndrome: A functional gastrointestinal disorder characterized by bloating, cramping, and left upper quadrant pain due to trapped gas or colonic spasm
Colorectal cancer: Tumors may arise at the splenic flexure and are often more challenging surgically due to the sharp angle and dual blood supply
Endoscopic navigation: The flexure may be difficult to pass during colonoscopy due to its fixed and angulated position
Referred pain: Disorders here may cause referred pain to the left upper abdomen or back
Imaging studies such as CT, barium enema, and colonoscopy help evaluate pathology at the splenic flexure. Awareness of its vascular vulnerability and fixed location is essential in both medical and surgical gastroenterology.
Did you know? The stomach acid is strong enough to dissolve metal, but the stomach lining protects itself from being digested!