What does "accessory motion" refer to in joint mechanics?

Accessory motion refers to the movement of joint surfaces relative to each other during functional movements. This concept is crucial in understanding how joints function, as it encompasses the small, subtle movements that occur between the articulating surfaces. These accessory movements include roll, glide, and spin, which contribute to the overall function of the joint but are not typically voluntary movements.

When assessing joint mechanics, knowing how the surfaces move relative to each other helps ensure that joint stability and proper biomechanics are maintained, which can impact injury prevention and rehabilitation protocols. Furthermore, recognizing the significance of accessory motions supports clinicians in diagnosing joint dysfunction and designing effective treatment strategies.