British Journal of Radiology 74 (2001),756-758 © 2001 The British Institute of Radiology
Alternative radiographic projections of the ulnar coronoid process
F J Tomás, RT
Department of Radiology, Hospital de la Santa Creu i Sant Pau, Avda. Sant Antoni Ma Claret 167, 08025 Barcelona, Spain
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Abstract
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We describe two radiological projections that ensure correct imaging of the ulnar coronoid process and that can be carried out with minimum mobilization of the joint, thus being practical in virtually all patients.
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Introduction
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The incidence of lesions of the coronoid process of the elbow is relatively low. Isolated fractures are rare and are usually found in association with dislocations of the joint or in cases of multiple fractures in which they frequently combine with splintered fractures of the radial head. Appropriate treatment depends on correct diagnosis, and determining the origin of the splintered fragment is particularly important.
Plain radiography is indispensable for studying the coronoid process. Oblique 45° projection of the elbow in internal rotation and extension is the most commonly employed technique, supplementing the standard anteroposterior and lateral projections [1, 2]. Other described techniques [3, 4] are derived from the oblique 45° radial head–capitellum projection described by Greenspan and Norman [5]. All these projections suffer from the disadvantage that they are impractical in patients experiencing mobility difficulties in the shoulder joint, since they require extension and abduction of the arm.
This article describes two radiological projections that ensure correct imaging of the coronoid process and that can be carried out with minimum mobilization of the joint, thus being practical in virtually all patients.
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Methods
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Oblique 45° projection with abduction of the arm
For this projection, the patient is seated on a chair alongside the examination table. The elbow should be maintained bent at an angle of 90° and the arm is then abducted 45°, supporting the forearm over the radiographic cassette on the table. The X-ray beam will be perpendicular to the radiographic cassette and will focus on the joint (Figure 1a
). The coronoid process will be seen clearly since the radial head will be superimposed over the ulnar metaphysis, and the condyles over the humeral metaphysis (Figure 1b).
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Figure 1. Oblique 45° projection with abduction of the arm. (a) Patient positioning. (b) Resulting image.
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Oblique 45° lateromedial projection with anterior displacement of the arm
The patient is seated on a chair in front of the examination table on which the radiographic cassette is situated. The arm is brought forward slightly, sufficiently for the elbow to be forward from the patient's trunk and at an angle greater than 90°. The dorsal side of the forearm is placed over the radiographic cassette. The X-ray beam will be angled at 45° in a lateromedial direction and will focus on the elbow flexure (Figure 2a). The image of the coronoid process will be slightly elongated and magnified due to the angle of thebeam with respect to the joint and the film. The external condyle will be superimposed over the humeral metaphysis, since the radial head will be above the ulnar metaphysis, and both will appear elongated and magnified (Figure 2b).
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Figure 2. Oblique 45° lateromedial projection with anterior displacement of the arm. (a) Patient positioning. (b)Resulting image.
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Discussion
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Conventional radiography of the traumatised elbow does not always succeed in determining the origin of the resultant bone fragments. Carrying out oblique projections in patients with limited mobility of the extremity is not always possible, since it is necessary to either displace the arm anteriorly or to abduct it. The techniques presented here do not have these drawbacks. The oblique 45° projection with abduction is very simple to carry out, and the arm need only be abducted half as much as in the techniques derived from the oblique radial head–capitellum projection [3, 4]. The image obtained of the coronoid process is identical to that in the standard oblique projection. It is an ideal projection for periodical checks of lesions of the coronoid process. However, owing to superimposition of the humeral condyles, it is not appropiate for imaging of the distal humerus.
The oblique projection with anterior displacement of the arm can be performed on a patient whose arm is bandaged to the trunk, and it is sufficient to move the arm forward slightly, just enough to displace the elbow from the lateral plane with respect to the trunk. The advantage of this technique over the previous one is that it allows examination of the joint in two oblique planes without movement of the patient. All that is necessary is a lateromedial angle of 45° for examination of the coronoid process, or mediolateral for the radial head [6]. This is especially important in splintered fractures in which it is necessary to examine the entire proximal forearm, and the technique saves time, is more comfortable for the patient and does not involve any loss of quality in the resulting image.
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Acknowledgments
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We thank Mrs Anahita Saheb for assistance in translating this work into English.
Received for publication January 18, 2001.
Revision received April 23, 2001.
Accepted for publication May 1, 2001.
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References
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Ballinger PW. Merrill's atlas of radiographic positions and radiologic procedures (7th edn). St Louis, MO: Mosby-Year Book Inc., 1992.
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Guilbeau JC, Mouelhi MM, Nahum H. Les profils modifiés du coude en traumatologie. J Radiol 1986;67:439–44.[Medline]
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Tomás FJ, Carbó L. Nueva proyección para el diagnóstico de fracturas de la apófisis coronoides del cúbito. Radiología 1992;34:69.
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Greenspan A, Norman A. The radial-head, capitellum view: useful technique in elbow trauma. AJR 1982;138:1186–8.[Free Full Text]
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Tomás FJ, Proubasta IR. Modified radial head–capitellum projection in elbow trauma. Br J Radiol 1988;71:74–5.[Abstract]
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Abstract
Introduction
