01 / Location & anatomical relationships
At the upper corner of your torso, where each arm begins.
02 / Structure & organization
The shoulder complex includes the glenohumeral, acromioclavicular and sternoclavicular joints and movement of the scapula over the thorax. The rotator cuff centers the humeral head as larger muscles move the arm.
03 / Function
Its bones and muscles let your arm reach in many directions.
04 / Mechanism
Several joints work together at the shoulder. The upper-arm bone meets a shallow socket in the shoulder blade, and nearby muscles guide it. The shoulder blade also slides over the ribs as you reach upward.
Working together: muscular system
When you bend your elbow, some muscles contract while others relax. Their coordinated pull moves the bones at the joint.
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Connect structure with function
Arm elevation requires coordinated scapular and humeral motion. The shoulder's large range depends heavily on soft-tissue control around a relatively shallow socket.
Check your understanding
Locate the shoulder 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.