In a vehicle accident, the musculocutaneous nerve was completely severed, but still the person was able to weekly flex the elbow joint. All of the following muscles are responsible for this flexion, EXCEPT:

Muscles involved in elbow flexion are biceps brachii/biceps, brachialis, brachioradialis, extensor carpi radialis longus/ long radial extensor, pronator teres, palmaris longus, flexor carpi radialis and flexor carpi ulnaris.Pronator teres has two heads a humeral and an ulnar head. The ulnar head arises from the medial border of coronoid process of ulna. And both the heads get united and the combined muscle passes obliquely across the proximal forearm for inseion into lateral surface of radius. This muscle is primarily involved in the rapid pronation movements of the forearm.Ref: Muscle Exercises Encyclopedia page 306. Clinical Anatomy: (a Problem Solving Approach) By Neeta V. Kulkarni page 153.