BOC Domain 4 Treatment and Rehab Practice Test 2026 – Complete Guide to Therapeutic Modalities

D2 extension moves the arm diagonally from a high/outward position toward a lower/inward position, and the timing runs from proximal to distal. The shoulder starts by extending, establishing the base of the diagonal path. After that, the forearm pronates, guiding the hand downward and inward, and finally the fingers flex to complete the grasp pattern. This proximal-to-distal sequence fits the functional flow of a down-and-in diagonal movement, where the larger proximal segment initiates the motion and the distal segments follow to finish the action. The other options don’t match this directional sequence or the typical distal progression seen in D2 extension.