There are several ways to depict the structures of the shoulder, which consist of muscles, tendons, bones, cartilage and soft tissue.
When deciding which medical imaging technique should be used, there are a couple of factors that need to be taken into account. Firstly, one has to consider the suspected clinical diagnosis. Together with the knowledge of the advantages and limitations of the various medical imaging techniques ( i.e. conventional radiography, ultrasound, computer tomography and magnetic resonance), one has to make an informed decision which technique would best suit the specific situation.
Hodler et al. recommend to start scanning with conventional x-rays taken from at least two planes, since this method gives a wide first impression and even has the chance of exposing any frequent shoulder pathologies, i.e. decompensated rotator cuff tears, tendinitis calcarea, dislocations, fractures, usures and/or osteophytes. Furthermore, x-rays are required for the planning of an optimal CT or MR image.
Conventional x-rays and ultrasonography are the primary tools used to confirm a diagnosis of injuries sustained to the rotator cuff. For extended clinical questions, imaging through Magnetic Resonance with or without intraarticular contrast agent is indicated.
The conventional invasive arthrography is now-a-days being replaced by the non-invasive MRI and US and is used as an imaging reserve for patients who are contraindicated for MRI, for example pacemaker-carriers with an unclear and unsure ultrasonography.
Extracted from Wiki: http://en.wikipedia.org/wiki/Shoulder under the Creative Commons Attribution-ShareAlike License