01 / Location & anatomical relationships
Between your shoulder and elbow.
02 / Structure & organization
The humerus separates anterior and posterior muscle compartments. Biceps brachii, brachialis and coracobrachialis lie anteriorly; triceps dominates posteriorly. Major vessels and nerves travel through the region toward the elbow and forearm.
03 / Function
The bone inside it is called the humerus.
04 / Mechanism
Muscles attach around the humerus and cross the shoulder or elbow. The biceps helps bend the elbow, while the triceps straightens it. When one action is needed, the muscles coordinate rather than all pulling equally.
Part of a bigger picture
The upper arm belongs in our arms & hands collection. Explore the nearby parts to see how this area of the body fits together.
Explore arms & hands →FOR DEEPER STUDY
Connect structure with function
Biceps contributes to both elbow flexion and forearm supination. Triceps extends the elbow, illustrating how attachment positions determine the direction of muscle action.
Check your understanding
Locate the upper arm in relation to its neighbors. Explain how the structural features described above support its function, then distinguish it from a nearby structure with a different role.
Keep learning
Continue with OpenStax Anatomy and Physiology for system-level study. This atlas is educational and has not undergone independent medical peer review.