What is the primary role of the biceps brachii?

The primary role of the biceps brachii is to flex the elbow. This muscle is located in the upper arm and is particularly well-known for its appearance as a prominent muscle when flexing the arm. When the biceps contract, they shorten and pull the forearm toward the shoulder, resulting in the bending of the elbow joint.

In addition to this primary action, the biceps brachii also assists with shoulder flexion and supination of the forearm, which further emphasizes its importance in movements involving the arm and hand. Understanding this muscle's primary function is crucial for grasping how various movements of the upper limb are coordinated.