In the context of injuries, which option represents an objective sign that can be measured?

A sign is an objective indication of a medical condition that can be observed or measured by someone other than the patient, such as a healthcare professional. In the context of injuries, signs can include quantifiable reactions, such as swelling, bruising, or range of motion restrictions, which can be documented through various assessments or diagnostic tools.

In contrast, a symptom is a subjective experience reported by the patient, such as pain or fatigue, and cannot be measured objectively. The mechanism refers to the process or reason behind an injury, providing insight into how the injury occurred but not serving as a measurable indicator. Differential diagnosis is the process of distinguishing between two or more conditions with similar signs or symptoms and is a systematic approach, rather than an objective sign itself. Therefore, the correct identification of a sign is key to assessing and diagnosing injuries effectively.