A 45-year-old male arrived at the emergency depament with injuries to his left elbow after he fell in a bicycle race. Radiographic and MRI examinations show a fracture of the medial epicondyle and a torn ulnar nerve. Which of the following muscles would be most likely to be paralyzed?

Fracture of the medial epicondyle often causes damage to the ulnar nerve due to its position in the groove behind the epicondyle. The ulnar nerve innervates one and a half muscles in the forearm--the flexor carpi ulnaris and the medial half of the flexor digitorum profundus. The flexor digitorum superficialis is innervated by the median nerve and the biceps brachii by the musculocutaneous. The radial nerve innervates both the brachioradialis and supinator muscles.