Final answer:
The extensor digitorum muscle is responsible for extending the fingers and is innervated by the radial nerve. It is not a flexor muscle and originates from the lateral epicondyle of the humerus.
Step-by-step explanation:
The correct statement regarding the extensor digitorum muscle is that it is responsible for extending the fingers. It is not a flexor muscle but an extensor muscle. It is innervated by the radial nerve. Lastly, it originates from the lateral epicondyle of the humerus.