How do joint surfaces move in accessory motion?

Accessory motions refer to the subtle movements that occur between joint surfaces, which are crucial for normal joint function and movement. These motions include spin, roll, and glide, which collectively allow for a more versatile range of motion than simple rotation or linear movement.

Spin involves the rotation of one surface around another fixed surface, while rolling occurs when one surface rolls over another, creating a curve in motion. Glide (or translation) refers to the linear movement of one joint surface over another, which can happen simultaneously with rolling or spinning. Together, these motions accommodate the dynamic needs of various activities, helping to reduce friction and distribute loads across joint surfaces evenly.

Understanding accessory motions is essential for professionals in athletic training and rehabilitation because they influence joint stability, range of motion, and overall functional mobility. Recognizing how these movements contribute to joint mechanics can help in diagnosing injuries and developing effective treatment plans.