What muscles are used when turning a doorknob?

Answer 1

biceps brachii,pronator quadratus,supinator/pronator teres(depending on the direction of rotation) for turning and flexor digitorum superficialis and flexor digitorum profundus for flexing the fingers and palm to hold the key in place. The main muscle however in turning a key is biceps brachii,while pronator quadratus hold the two bones of the forearm together.the supinator or pronater teres supinate or pronate the arm respectively.

Answer 2

While turning a key the hand muscles are only required to hold the key in place.To do so the muscles flexor digitorum superficialis, flexor digitorum profundus, palmar interossei and lumbricals are used to flex the hand and the fingers.

Answer 3

The biceps brochii is the main forearm muscle that is used wen turning a key. The pronator quadratus holds this muscle in place.