

The Inverted Supinator Sign is a common neurological test used in the physical assessment of upper motor neuron lesions.
According to Cook et al. (2009), the inverted supinator sign has a sensitivity of 61% and specificity of 78%. The clinical value of this test as a stand-alone test is weak.
To conduct the test have the patient in sitting position. Support the patient’s forearm with your arm to ensure that it is relaxed. Slightly pronate the forearm and locate the styloid process of the radius at the attachment of the brachioradialis. Then apply a quick series of taps near the styloid process using a reflex hammer.
A positive test will show in finger flexion or slight elbow extension.
Other common tests to screen for upper motor neuron lesions are: