In addition to pain, what primary physical exam finding might indicate a sprained ankle?

Joint instability is a primary physical exam finding that can indicate a sprained ankle due to the nature of the injury. A sprain occurs when the ligaments, which connect bone to bone and support the joint, are stretched or torn. This often leads to a decreased ability of the joint to maintain its normal stability.

When assessing an injured ankle, if joint instability is observed, it suggests that the ligamentous support has been compromised, making the joint more prone to further injury or misalignment during movement. This finding will often be evaluated through specific stress tests performed by the clinician, which can reveal excessive motion that would not normally occur in a stable ankle joint.

While muscle rigidity, skin discoloration, and heat sensation can occur with various injuries, they are not definitive indicators of a sprained ankle. Muscle rigidity may suggest muscle strain or another type of injury rather than ligament damage. Skin discoloration can be associated with bruising, but it is not specific to sprains and can occur in various trauma scenarios. Heat sensation might indicate inflammation but does not specifically correlate to the mechanical stability of the ankle joint. Therefore, joint instability remains the most direct and relevant physical examination finding for diagnosing a sprained ankle.