The Radial Head—Capitulum View

The radial head-capitulum view is a modified lateral view of the elbow that is obtained by angling the tube 45 degrees toward the radial head. This results in projection of the radial head ventrally and eliminates overlap of other bones. The radial head-capitulum view also separates the humeroradial and humenoulnar articulations.

Practically speaking, there are several ways of obtaining the view, nicely reviewed and illustrated by Hobbs (2005):

• Sitting Axial Lateromedial Projection (Coyle Method): The patient is seated on a chair at the end of the examination table with the elbow flexed at about 90° (exact 90° flexion is not necessary) and the palm facing the film and table top. The x-ray tube is angled 45° in a lateromedial projection with the central ray directed to the mid-elbow joint.
• Recumbent axial lateromedial projection (Coyle Method): The elbow is flexed at about 90° (exact 90° flexion is not necessary) with the palm facing the film. The x-ray tube is angled 45° in a lateromedial projection with the central ray directed to the mid-elbow joint.
• Sitting 45° axial mediolateral projection: The patient is seated on a chair at the end of the examination table with the dorsal side of the forearm facing the film. The arm is brought slightly forward so that the elbow is at an angle of greater than 90°. The tube is directed at a 45° mediolateral projection with the central ray directed to the mid-elbow joint. This is a good projection in that it can be performed on a patient in an arm sling. In addition, by obtaining a 45° lateromedial projection in the same position, we can get a good look at the coronoid process.

References

• Greenspan A, Norman A. The radial head, capitellum view: useful technique in elbow trauma. AJR Am J Roentgenol. 1982 Jun;138(6):1186-8.
• Greenspan A, Norman A, Rosen H. Radial head-capitellum view in elbow trauma: clinical application and radiographic-anatomic correlation. AJR Am J Roentgenol. 1984 Aug;143(2):355-9.
• Hobbs DL. Fat pad signs in elbow trauma. Radiol Technol. 2005 Nov-Dec;77(2):93-6.