What Purpose Do the Biceps Have?

Without the biceps-brachii muscle turning your palm upward, you couldn't eat, drink or text. Controlling coordinated and complex movements at the elbow and forearm, the biceps-brachii, or biceps, is a strong muscle responsible for flexion and supination. Whether hanging a picture frame or just drinking a cup of coffee, this muscle allows you to bend your elbow and flex your forearm.

Bending the Elbow

• The biceps provide balance and strength.

  The muscles, tendons and ligaments attached to the forearm, elbow and upper arm provide movement in the articulations of the radius, elbow joint and humerus. The biceps muscle attaches to the forearm just below the elbow at the proximal end of the radius, the end nearest to the torso. The other end of this muscle attaches to the proximal end of the upper arm. Acting as a pulley system, the shoulder end of the biceps pulls the elbow in toward the body, while the end of the muscle closest to the forearm provides stability and adds strength to the flexing elbow. This balancing act allows you to raise and lower the elbow with precise control.

Flexing the Foream

• Muscle spindle cells in this tissue signal movement in the biceps.

  Attaching to the wrist and elbow, the forearm supinates, or rolls palm forward. In this position, in which you could hold a bowl of soup, the forearm requires assistance from the biceps in order to lift the bowl to your mouth. Without the pulley action of the biceps, the forearm and wrist would lack sufficient flexibility to allow you to feed yourself, dress, brush your teeth or arm wrestle. The biceps brachii flexes the supinated forearm at the elbow, according to "Wheeless' Textbook of Orthopedics." The distal end of the muscle, attaches to the radius, the bone in the forearm on the thumb side of the arm.

Supinating the Forearm

• When the arms are resting at your sides, the back of the hand faces out in pronation. Rolling the forearm and hand inward and upward, the biceps brachii muscle pulls the radial bone into supination upon upward rotation of the forearm. Working in unison, the biceps and supinator muscles of the forearm allow the palms to face upward, according to Henry Gray's "Anatomy of the Human Body." If you grasp the biceps of the left arm with your right hand and rotate the left palm and forearm, you can feel the rolling movement of the biceps brachii.

Balance and Power

• Similar to rope, tendons and ligaments anchor muscle to bone with many layers of strong tissue. Providing strength and support, the biceps tendon and ligament fasten the radius and humerus bones to the elbow. This supinating, two-headed muscle and tendon, allow delicate and precise work, such as buttoning your coat, as well as strength and stability, such as budging the refrigerator to sweep underneath it.