The duodenal bulb, approximately 5cm in length, originates from the pylorus of the stomach and extends towards the right posterior direction. It turns abruptly into the descending part behind and below the neck of the gallbladder, where the transition point is known as the superior duodenal flexure. The segment of the duodenal bulb, approximately 2.5cm proximal to the pylorus, features a thinner wall and a smoother mucosal surface with few or no annular folds. This segment is referred to as the duodenal bulb and is a common site for duodenal ulcers. However, duodenal ulcers, statistically, do not progress to cancer.
The duodenum, connecting the pylorus above and the cecum below, extends for a total length of 5 to 7 meters in adults, and is divided into three parts: duodenum, jejunum, and ileum. The duodenum, specifically the duodenum duodenum, lies between the stomach and jejunum. It measures approximately 20 to 25cm in length and 4 to 5cm in diameter in adults. It is closely adhered to the posterior abdominal wall and is the shortest, largest in diameter, deepest, and most fixed segment of the small intestine. Shaped like a "C," it encircles the pancreatic head and can be divided into four parts: superior, descending, horizontal, and ascending. It functions like a funnel, collecting pancreatic juice, bile, and gastric juice. Without it, digestion is impaired, and the consumption of meat becomes difficult. The duodenum plays a significant role in digestion and absorption, and its absence can have a detrimental impact on food digestion. As a vital organ for digestion and absorption, food undergoes physicochemical digestion in the stomach, passes through the duodenum, and is further processed through its physicochemical actions to absorb nutritional components.
