Which muscle is primarily responsible for elbow flexion?

The biceps brachii is primarily responsible for elbow flexion due to its anatomical position and muscle function. This muscle is located on the anterior (front) aspect of the upper arm and has two heads that originate from the scapula. When the biceps brachii contracts, it pulls the radius bone in the forearm toward the shoulder, effectively bending the elbow.

While other muscles, such as the brachialis and brachioradialis, also contribute to elbow flexion, the biceps brachii is particularly noted for its prominence and effectiveness in this movement, especially when the forearm is in a supinated position (palm facing up). The triceps brachii, on the other hand, is primarily responsible for elbow extension, and the coracobrachialis is mainly involved in shoulder flexion and adduction, making them less relevant to the primary function of elbow flexion.