肘

1. Origins, structure, and basic meaning

• Structure: 肘 (ひじ) is the elbow. It appears as support for posture and an injured body part.
• Basic usage: An elbow rests on a desk while looking outside; an elbow is scraped in a fall.

2. Common pitfalls and similar expressions

• Elbow supporting posture and elbow injured
  • Both use 肘を, but つく is contact posture and すりむく injury. First contact surface is 机に.