The superficial branch is a completely different topic. It is a sensory branch with no motor function so the patient presents with “Wartenberg Syndrome” which is superficial sensory disturbance in the superficial branch of radial nerve distribution. This distribution is on the dorsal side of the thumb and index finger. This nerve is commonly damaged by trauma as it is in the subcutaneous space in the distal forearm. In the proximal forearm it is relatively protected by the brachioradialis muscle.
It may also be damaged by a needle injury during a Dequervains tenosynovitis injection!
So I follow it if these symptoms are present.
Steve