Radiographic Pearls:
Radiographing the Scapula

Dr. Bob Toal, DACVR

Strict adherence to proper technique and positioning can facilitate radiographic interpretation. This concept is especially true for the scapula. Poorly positioned radiographs or failure to take the proper views can cause one to miss the extent of the lesion or the lesion itself.

Correct positioning of the scapula is easy if several points are kept in mind. The body and spine of the scapula are at right angels to each other. This means that two views are needed to adequately project both parts. Also, the scapular body is superimposed over the ribs. If the leg is extended, the shoulder joint is clearly visualized but the ribs remain superimposed over the scapular body. Therefore at least two different positioning methods are needed for a complete unobstructed lateral view of the scapula. Also, to see the scapular spine fully, a posterior-anterior projection is recommended. Thus, a minimum of three views are needed for a complete scapular study. The following discussion will focus on how to do a radiographic evaluation of the scapula.

Lateral Projections:

Two methods of projection should be used to evaluate the scapula laterally. In these methods, the involved leg is placed on the down side with the x-ray beam directed medial to lateral. Sedation will help with fractious patients. Cassette placement is indicated in the diagrams and the x-ray beam is centered over the scapula or the shoulder joint as needed.

1) The cranial thoracic projection is best for the scapular neck and the shoulder joint. It is not good for the scapular body thus it needs to be supplemented with another view. See the diagram below.

Cranial Thoracic position

2) The dorsal thoracic projection is used to isolate the scapular body laterally in an unobstructed plane away from the ribs. In this view the body is visualized "en face" and the spine is seen end-on. Consequently, lesions of the spine may be missed with this technique thus it needs to be supplemented with a PA projection.

Dorsal Thoracic Position

Posterior-Anterior(PA)Projection.

3) The posterior-anterior projection is used for the scapular body, spine and the shoulder joint. The patient is placed in dorsal recumbency with the rear legs pulled caudally and the forelegs cranially. The sternum is rotated 300 away from the affected side. This maneuver isolates the scapula and produces a true PA view. If needed, this view can be obtained in a recumbent patient utilizing a horizontal beam.

continued on page 6 - see Radiology

SouthPaws Veterinary Referral Center Newsletter, Winter 2003