Traction should be perpendicular to the treatment plane, while glides are parallel to the treatment plane

3.7. Ask questions to the words in italic.

1. Pure gliding can occur only if the two articulating surfaces are congruent where either both are flat or both are curved. 2. Since virtually all articulating joint surfaces are incongruent, meaning that one is usually flat while the other is more curved, it is more likely that gliding will occur simultaneously with a rolling motion. 3. Rolling does not occur alone because this would result in compression or perhaps dislocation of the joint. 4. Although rolling and gliding usually occur together, they are not necessarily in similar proportion, nor are they always in the same direction. 5. If the articulating surfaces are more congruent, more gliding will occur, whereas if they are less congruent, more rolling will occur.

3.8. Complete the sentences with words from the box.

1. Rolling will always … in the same direction as the movement. 2.

For example, in the knee … when the foot is fixed on the ground, the femur will always roll in an anterior direction when moving into knee extension and conversely will roll posteriorly when moving into flexion. 3. The direction of the … … of motion is determined by the shape of the articulating surface-that is moving. 4. If you consider the shape of two articulating surfaces, one joint surface can be determined to be convex … … while the other may be considered to be concave in shape. 5. In the knee, the femoral condyles would be considered … … … …, while the tibial plateau would be the concave joint surface. 6. In the glenohumeral joint, … … … would be the convex surface, while the glenoid fossa would be the concave surface.