Which term describes joints such as the ankle, hip, thoracic, glenohumeral, upper cervical, and wrist?

• A. Global Joints
• B. Hinge Joints
• C. Mobile Joints
• D. Stable Joints

Answer: (C)

The key idea here is mobility: these joints are all designed to move through a wide range of motions in multiple planes. Each of the listed joints is a highly mobile, synovial (diarthrodial) joint with a joint capsule, ligaments, and cartilage that allow various movements. For example, the ankle and wrist enable complex motions like flexion/extension and side-to-side deviations; the hip and shoulder (glenohumeral) are ball-and-socket joints with extensive rotational freedom; the thoracic region and upper cervical spine permit rotation and bending; together these joints support activities from walking and running to reaching and manipulating objects. Stability is still provided by surrounding muscles and ligaments, but the defining feature of these joints is their mobility.