Which reflex is being tested here?

Finger flexor reflex/Hoffmann's reflex with patient's hand in supination. It involves loosely holding the middle finger and flicking the fingernail downward, allowing the middle finger to flick upward reflexively. A positive response is seen when there is flexion and adduction of thumb on same hand. Brachioradialis reflex /Supinator reflex: observed by striking brachioradialis directly with a reflex hammer when the patient's arm is relaxing. This reflex is carried by the radial nerve (spinal level: C5, C6) Waenberg sign: Neurological sign consisting of involuntary abduction of the fifth (little) finger, caused by unopposed action of extensor digiti minimi.