Arthrokinematics refers to the movement of joint surfaces.
The angular movement of bones in the human body occurs as a result of a combination of rolls, spins, and slides.
- A roll is a rotary movement, one bone rolling on another.
- A spin is a rotary movement, one body spinning on another.
- A slide is a translatory movement, sliding of one joint surface over another.
The convex-concave rule is the basis for determining the direction of the mobilizing force when joint mobilization gliding techniques are used to increase a certain joint motion. The direction in which sliding occurs depends on whether the moving surface is concave or convex.
- Concave = hollowed or rounded inward
- Convex = curved or rounded outward
If the moving joint surface is convex, sliding is in the opposite direction of the angular movement of the bone. If the moving joint surface is concave, sliding is in the same direction as the angular movement of the bone.
In glenohumeral articulation, the concave glenoid fossa articulates with the convex humeral head.
- The glenohumeral posterior glide increases flexion and internal rotation.
- The glenohumeral anterior glide increases extension and external rotation.
In humeroradial articulation, the convex capitulum articulates with the concave radial head.
- The dorsal or posterior glide of the head of radius increases elbow extension.
- The volar or anterior glide of the head of the radius increases elbow flexion.
In articulation of the hip joint, the concave acetabulum articulates with the convex femoral head.
- The hip posterior glide increases flexion and internal rotation.
- The hip anterior glide increases extension and external rotation.
In tibiofemoral articulation, the concave tibial plateaus articulate on the convex femoral condyles.
- The tibiofemoral posterior glide increases flexion.
- The tibiofemoral anterior glide increases extension.
In articulation of the tabocrural joint, the convex talus articulates with the concave mortise (tibia and fibula).
- The talocrural dorsal or posterior glide increases dorsiflexion.
- The talocrural ventral or anterior glide increases plantarflexion.
Kisner, C., Colby, L.A. (2002). Therapeutic Exercise: Foundations and Techniques, 5th ed. F.A. Davis: Philadelphia.
Reprinted with permission from Arthrokinematics, Justine Haroon, ed. In Physiopedia, http://www.physio-pedia.com/Arthrokinematics. Accessed August 21, 2012.