骨髄(こつずい)

骨髄(こつずい) is the soft tissue inside bones that produces blood cells. Composed of 骨(こつ) (bone) + 髄(ずい) (marrow, core).

MEDICAL TERMS:

• 骨髄(こつずい)移植(いしょく): bone marrow transplant
• 骨髄(こつずい)バンク: bone marrow registry/bank
• 骨髄(こつずい)検査(けんさ): bone marrow examination/biopsy
• 骨髄(こつずい)提供者(ていきょうしゃ)/ドナー: bone marrow donor

IDIOMATIC USE:

• 骨髄(こつずい)に染(し)みる: to be deeply felt, to penetrate to the marrow
• 骨髄(こつずい)に達(たっ)する: to reach the bone marrow (deeply affecting)

These idioms express something that affects one profoundly.

IN JAPAN:
骨髄(こつずい)バンク (Japan Marrow Donor Program) campaigns are well-known. Registration drives are a common topic in news and public health messaging.