Anatomy, Shoulder and Upper Limb, Biceps Muscle

Excerpt

The biceps brachii, or simply "biceps," is a large, thick, fusiform muscle on the upper arm's ventral portion (see Image. Right Upper Extremity Surface Anatomy). As the name implies, this muscle's proximal attachment has 2 heads. The short head is sometimes referred to as "caput breve," while the long head is also called "caput longum." Distally, the biceps brachii continues as the bicipital aponeurosis, crossing the elbow joint to insert on the radius and forearm fascia. This muscle is a forearm flexor when extended but becomes the forearm's most powerful supinator when flexed.

The conditions affecting the biceps brachii are often caused by muscle overuse or trauma. For example, the "popeye deformity," common to baseball pitchers, arises from a ruptured long head tendon due to chronic wear and tear. Consequently, the muscle forms a ball at the anterior mid-arm. The biceps brachii is also an important landmark for locating the brachial artery during physical examination and ultrasound-guided arterial cannulation.

This article discusses the biceps brachii's anatomy and clinical importance.