Answer:
a. a joint's maximum range of motion
Step-by-step explanation:
A goniometer is a device that is used to measure the maximum arc of motion made by a joint. The traditional goniometer consists of a protractor and two extending arms ,one of the arms is movable while the other one is stationary.To take measurements the center of the goniometer is aligned with the center of a joint. Then the arm of the goniometer is moved until it aligns with the limb that has been moved to a maximum position that the joint allows. The angle made between the two arms of the goniometer is measured in degrees and is the maximum range of motion of the joint.