Compression

Compression: Compression is an arthrokinematic motion. 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. An anatomical example would include forces that direct one bone surface into another resulting in a reduction in intra-articular volume. Although often thought of as a "destructive force", it is likely best to consider compression as a naturally occurring, and stabilizing force. Any arthrokinematic force in excess (spin, glide, roll, traction) may be viewed as potentially deleterious.

Image: By BruceBlaus - Own work, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=29987033