Arthrokinematic Motion (Arthrokinematics)
Arthrokinematic Motion: Small amplitude motions between bone surfaces at a joint. The arthrokinematic motions include roll, glide (slide or translation), spin, compression, and distraction (traction). Arthrokinematic motions accompany osteokinematic motions to maintain joint congruence.
- Synonyms of Arthrokinematic Motion: arthrokinematics, passive accessory motion, joint play, and component motion.
- Example of Arthrokinematic Motion: During shoulder abduction, the humeral head rolls superiorly in the glenoid fossa. This must be accompanied by an inferior glide of the humeral head so that the center of the humerus remains close to the center of the glenoid fossa (joint congruence is maintained).
- Osteokinematic Motion versus Arthrokinematic Motion: Osteokinematic motions are the motions commonly referred to as "joint actions," and include flexion, extension, abduction, adduction, etc. Arthrokinematic motions are the small motions between joint surfaces that aid in maintaining joint surface congruence and include spin, glide (slide), roll, etc. Range of motion (ROM) most often refers to osteokinematic motion, whereas passive accessory motion most often refers to arthrokinematic motion.
For more information on arthrokinematic motions, check out our course and video lecture:
Arthokinematic Motion Definitions:
- Roll : Roll is an arthrokinematic motion. The movement of an object, usually in one direction (inferiorly, medially, etc.), by turning over and over on its axis. Similar to the way a ball might roll across a field. An anatomical example would be the posterior roll of the humeral head in the glenoid fossa during external rotation of the humerus.
- Glide : A linear movement of an object across a surface parallel to the plane of that surface. Similar to the way skis slide down a snowy slope. An anatomical example would be the posterior glide of the humeral head during internal rotation of the humerus to maintain congruence with the glenoid fossa.
- Spin : A rotational movement around a single axis. Analogous to the way a top or dreidel "spins" on a tabletop. An anatomical example would be the posterior spin of the femoral head in the acetabulum during hip flexion.
- Compression : The approximation of two surfaces; that is, a force that reduces the space or increases the pressure between two surfaces. Similar to the way the teeth are "clenched" together during a bite.
- Distraction (traction) : Distraction is an arthrokinematic motion. A force applied that separates two surfaces; that is, a force that increases the space or decreases the pressure between two surfaces. Similar to the way a suction cup is pulled from a window.