3. R. shoulder arthrogram, AP projection

An arthrogram is an X-ray study of a joint obtained after the injection of sterile, water-soluble iodine-containing liquid into the joint cavity. The radiopaque contrast provides more anatomic information than does the plain film alone. In most cases these studies have been supplanted by MRI (see Images #4, #5 & #6 in this unit), which can yield more information about the joint and surrounding structures without the risks associated with an arthrogram (infection, allergic reaction to the contrast agent, etc.).

However, this image is still useful in illustrating radiologic anatomy since it displays normal parts of the joint (glenohumeral joint proper, axillary recess), and structures normally communicating with the joint (subscapular bursa, sheath of long head of biceps tendon). Note that the subcranial-subdeltoid bursa does not normally communicate with the joint and so does not fill with radiopaque contrast. Visualization in this manner would indicate a complete tear of the supraspinatus tendon.