National Physical Therapy Examination (NPTE) Practice Exam

According to the convex-concave rule, which glenohumeral joint mobilization technique is most appropriate for increasing motion to scratch the back?

1. Distraction with inferior glide

2. Anterio glide with abduction

3. Superior glide with approximation

4. Distraction with posterior glide

The correct answer is: Distraction with posterior glide

The correct answer focuses on the principles outlined in the convex-concave rule, which informs how to properly mobilize a joint based on the shape of the articulating surfaces. In the case of the glenohumeral joint, the rounded, convex humeral head moves over the concave glenoid fossa during arm movements such as reaching to scratch the back. Distraction with a posterior glide is specifically effective in this context because, when moving the arm backward and across the body (a common action in scratching the back), the humerus experiences a posterior roll. To facilitate this motion without restricting it, a distraction combined with a posterior glide can help increase this movement, enhancing both flexion and internal rotation. This mobilization technique also addresses the joint's accessory movements, which can alleviate tightness and improve range of motion effectively, making it the most suitable choice for this particular action. Understanding how each technique leverages the geometry of the joint is valuable for determining which mobilization will yield the best results for specific motions like scratching one's back.