血腫

1. Origins, structure, and basic meaning

• Structure: 血腫, read けっしゅ, denotes a localized collection of blood in body tissue outside the blood vessels.
• Basic usage: It names a small hematoma seen on imaging and the condition examined after a fall.

2. Common pitfalls and similar expressions

• Collected blood rather than skin color alone
  • It refers to blood collected in tissue outside vessels, not merely discoloration visible on the skin.