Final answer:
The biceps brachii muscle originates from the supraglenoid tubercle of the scapula and the coracoid process of the scapula. It inserts into the radial tuberosity of the radius bone and the bicipital aponeurosis. Its action is to flex the forearm at the elbow joint and assist in supinating the forearm and flexing the arm.
Step-by-step explanation:
The biceps brachii muscle originates from two points – the long head originates from the supraglenoid tubercle of the scapula, and the short head originates from the coracoid process of the scapula. The muscle then inserts into the radial tuberosity of the radius bone and the bicipital aponeurosis.
The action of the biceps brachii is to flex the forearm at the elbow joint. It also assists in supinating the forearm at the radioulnar joints, and flexing the arm at the shoulder joint. Additionally, it can provide additional power in forearm flexion.