The biceps brachii is one of the most recognized muscles in the human body, associated with visible strength and arm movement. This prominent muscle is situated on the front of the upper arm, spanning the distance between the shoulder and the elbow. Its main role involves controlling the movement of the forearm, allowing for a variety of daily actions.
Where the Bicep Is Located
The name “biceps” literally translates from Latin as “two heads,” which accurately describes this muscle’s unique anatomical structure. It is composed of a long head and a short head, both of which originate on the scapula, or shoulder blade. The long head begins at the supraglenoid tubercle, a small bony projection just above the shoulder socket. The short head starts nearby at the coracoid process, a hook-like structure on the front of the shoulder blade.
These two distinct muscle bellies merge together in the middle of the upper arm to form a single, thick muscle mass. This combined muscle then travels down the front of the humerus, crossing the elbow joint. The tendon of the biceps brachii attaches to the radius bone in the forearm at a specific point called the radial tuberosity. This attachment point enables the muscle to manipulate the forearm bone during movement.
How the Bicep Moves the Arm
The location and connection points of the biceps brachii allow it to perform two main actions at the elbow joint. The most commonly known function is elbow flexion, the act of bending the arm to bring the forearm closer to the upper arm, like when lifting an object. The muscle contracts and shortens, pulling the insertion point on the radius toward the origin points on the scapula.
The muscle also has a specialized function called forearm supination, which is the rotational movement that turns the palm of the hand upward. Because the biceps tendon inserts onto the radius bone, pulling causes the radius to rotate. This rotational power makes the biceps the strongest supinator of the forearm, an action utilized when turning a doorknob or using a screwdriver. The long head of the biceps also crosses the shoulder joint, which allows it to provide some assistance in raising the entire arm forward, known as shoulder flexion.
Keeping Your Biceps Strong and Safe
Strengthening the biceps typically involves exercises that incorporate its primary functions of elbow flexion and forearm supination. Movements like the standard bicep curl engage the muscle directly, particularly when the palm is facing upward. It is often beneficial to include compound movements, which are exercises that involve multiple joints, as these can promote overall arm and shoulder stability.
The biceps tendons are susceptible to common injuries, including tendonitis and tears, often occurring due to overuse or sudden, excessive force. Biceps tendonitis is an inflammation affecting the long head of the tendon near the shoulder, often resulting from repetitive overhead activity. Tears can happen either near the shoulder or at the elbow, sometimes producing a noticeable change in the muscle’s appearance. Avoiding overtraining and utilizing controlled movements with proper form helps reduce strain on the tendons, maintaining the health of this important muscle.