幽門

1. Origins, structure, and basic meaning

• Structure: 幽門(ゆうもん) is an anatomical term for the outlet of the stomach leading toward the small intestine.
• Basic usage: It is used when describing stomach anatomy or the route taken by stomach contents. Typical patterns are 胃の出口にある幽門 and 幽門を通る.

2. Common pitfalls and similar expressions

• Use it as a technical term
  • It names a specific anatomical part, so it is not used for an ordinary gate or exit.
• Difference from 胃
  • 胃(い) refers to the stomach as a whole, while 幽門 refers specifically to its outlet toward the small intestine.