What is the most sensitive test for detecting nerve injury in a finger after trauma?

The most sensitive test for detecting nerve injury in a finger after trauma is two-point discrimination. This test evaluates the ability to sense the difference between two closely spaced points on the skin. It is particularly effective in detecting fine touch and proprioceptive sensations, which are often impaired following nerve injuries.

Two-point discrimination is more sensitive than the other modalities listed because it assesses the integrity of the specific nerve pathways responsible for fine tactile sensations. When a nerve is injured, the ability to accurately perceive two distinct points diminishes, making this test a critical tool in diagnosing nerve damages, especially in areas like fingers where fine sensory functions are essential.

In contrast, light touch and pain sensation tests, while useful, do not provide as much detail regarding the functional status of small nerve fibers. Similarly, temperature sensation can be affected by broader aspects of skin integrity or circulation, rather than specifically indicating nerve function. Therefore, two-point discrimination stands as the most reliable and sensitive measure for evaluating nerve injury in fingers post-trauma.