noun
bursa
Anatomical term for a fluid-filled sac that reduces friction between tissues such as bone, muscle, and tendon.
肩の滑液包が炎症を起こすと、痛みが出ることがあります。
When the bursa in the shoulder becomes inflamed, it can cause pain.
Compound of 滑液 (synovial fluid) + 包 (sac, envelope). The term is a direct anatomical coinage.