joint capsule

This term is a specialized anatomical designation used primarily in medical, orthopedic, and biological contexts. It describes a specific structural boundary, and as such, it is rarely used in casual conversation unless discussing a medical diagnosis or surgical procedure.

In clinical settings, the term is frequently paired with descriptors like "ruptured," "inflamed," or "tightened" to indicate the pathological state of the joint. Because it refers to a specific biological structure, it follows standard English noun patterns but is almost exclusively restricted to technical registers.