What symptom distinguishes tendinitis from other musculoskeletal injuries?

The symptom that distinctly characterizes tendinitis is localized swelling and tenderness. Tendinitis specifically refers to the inflammation of a tendon, which is the tissue that connects muscle to bone. When this inflammation occurs, it's typical to see localized swelling around the affected tendon, along with tenderness when pressure is applied or the tendon is moved.

While chronic, low-grade pain may be present in tendinitis, it is not exclusive to this condition, as other musculoskeletal injuries may also present with similar pain patterns. Acute, severe pain can indicate many different types of injuries, but it does not specifically point to tendinitis, which generally presents with milder but more persistent symptoms. Joint locking is associated with different conditions, often relating to ligaments or intra-articular structures rather than tendons, making it an inadequate distinguishing symptom for tendinitis. Thus, the hallmark features of localized swelling and tenderness serve to differentiate tendinitis from other musculoskeletal injuries effectively.