A diagnostic examination of a joint where air and then a radiopaque contrast medium are injected into the joint space,x-rays are taken,and internal injuries of the meniscus,cartilage,and ligaments may be seen,if present,is:

A) arthroscopy.
B) goniometry.
C) arthrography.
D) thermography.

The diagnostic examination described involves the injection of a radiopaque contrast medium into the joint space, which is characteristic of arthrography. Arthroscopy is a different diagnostic technique that involves inserting a small camera into the joint and visualizing it directly. Goniometry measures joint range of motion, and thermography is a technique used to measure surface temperatures. Therefore, the only appropriate answer is C, arthrography.