Which joints are intended to produce movement in three planes and are prone to mobility restrictions?

• A. Hinge Joints
• B. Synarthrotic Joints
• C. Ball-And-Socket Joints
• D. Mobile Joints

Answer: (D)

Joints that move in three planes are ball-and-socket joints. Their shape and articulation allow motion around three axes: flexion–extension, abduction–adduction, and internal–external rotation. This tri-planar freedom comes from the spherical head in a cup-like socket, giving a wide range of motion but less inherent stability. Because of that, mobility restrictions are common and can arise from tight joint capsules and surrounding ligaments, muscle imbalances, or pathological changes like adhesive capsulitis, arthritis, or injuries that limit rotation, tracking, or overall motion. The shoulder and hip are the classic examples. In contrast, hinge joints largely move in a single plane, and synarthrotic joints are largely immobile, so they don’t fit the idea of three-plane movement. A term like “mobile joints” isn’t a standard anatomical category and doesn’t specify the motion pattern.