Hyporeflexia of upper limbs Brachioradialis hyporeflexia 2020-10-11T14:26:08Z The brachioradialis reflex is a deep tendon reflex involving the C5 and C6 nerve roots through its innervation by the radial nerve. To test brachioradialis reflex, the forearm is supported in a slightly pronated position. Then, the physician delivers a series of quick hits with the reflex hammer to the area of the styloid process of the radius at the point of brachioradialis insertion. Reduced intensity of the brachioradialis tendon reflex.