Final answer:
The biceps brachii, brachialis, and brachioradialis are forearm flexors involved in flexing the forearm, with the biceps brachii also assisting in supination and shoulder flexing. The brachialis adds power to forearm flexing, while the brachioradialis helps in quick flexion or gradual lifting.
Step-by-step explanation:
The biceps brachii, brachialis, and brachioradialis are all muscles that flex the forearm. The biceps brachii is known for crossing the shoulder and elbow joints to assist in this action and is also involved in supinating the forearm at the radioulnar joints as well as flexing the arm at the shoulder. The brachialis is located deep to the biceps brachii and provides additional power to the flexing motion. The brachioradialis, which is part of these anterior compartment muscles, can flex the forearm rapidly or help in lifting a load more gradually. Together, these muscles, with their associated blood vessels and nerves, make up the anterior flexor compartment of the arm.