## The Duodenojejunal Flexure and Ligament of Treitz **Key Point:** The **ligament of Treitz** (also called the **suspensory ligament of the duodenum**) is a fibromuscular band that anchors the duodenojejunal flexure to the posterior abdominal wall at the level of the L2 vertebra. ### Anatomy of the Ligament of Treitz **High-Yield:** The ligament of Treitz is derived from the peritoneum and contains smooth muscle (continuation of the diaphragm's crura). It acts as a natural "suspensory" structure. ### Structural Relationships | Landmark | Attachment | Function | |----------|-----------|----------| | **Ligament of Treitz** | From L2 vertebra/right crus of diaphragm to duodenojejunal flexure | Suspends and anchors the flexure | | **Duodenojejunal flexure** | Junction of D4 (4th part of duodenum) and jejunum | Marks transition from retroperitoneal to intraperitoneal small bowel | | **Location** | Left of midline, posterior to superior mesenteric vessels | Anatomical landmark for surgery | **Clinical Pearl:** The duodenojejunal flexure is a **fixed point** in the abdomen because of the ligament of Treitz. This is clinically important because: - It serves as a reference point for identifying small bowel loops during surgery. - Abnormal fixation or absence of the ligament can lead to **intestinal malrotation** and volvulus. - In **Superior Mesenteric Artery (SMA) syndrome**, the SMA may compress the duodenum just distal to the ligament of Treitz. **Mnemonic:** **"Treitz Tethers"** — The ligament of Treitz tethers (anchors) the duodenojejunal junction to the posterior abdominal wall. ### Embryological Basis The ligament of Treitz is a remnant of the dorsal mesentery and contains smooth muscle derived from the **right crus of the diaphragm**. This explains its muscular component and its role in suspending the duodenojejunal flexure [cite:Standring Anatomy 42e Ch 65]. 
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