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February 18, 2003 -- This article is the 13th in our series of white papers on radiologic patient positioning techniques for x-ray examinations. If you'd like to comment on or contribute to this series, please e-mail .For the humerus, anteroposterior (AP) and lateral radiographs constitute the basic examination. Both views should include the elbow and joints of the shoulder, with the elbow manifesting a true lateral configuration in the lateral projection. Technical factors
Positioning for an AP projection of the humerus
Evaluation criteria for AP projection of humerus
Positioning for a lateral projection of the humerus
Evaluation criteria for lateral projection of humerus
Radiographic positioning for the clavicle The radiographic evaluation of the clavicle requires AP and AP axial projections. Technical factors
Positioning for an AP projection of the clavicle
Positioning for an AP axial projection of the clavicle
Evaluation criteria for the clavicle
Radiographic positioning for the AC joint The AC joint is a small synovial joint between the lateral end of the clavicle and the medial aspect of the acromion of the scapula. It permits both gliding and rotary (elevation, depression, protraction, and retraction) movements. Although the AC joint is visualized in routine views of the shoulder, it may be superimposed on other osseous structures. Radiographs obtained in the frontal projection with a cephalad tilt of the incident beam of approximately 15° are superior in delineating abnormalities of this articulation. Stress radiographs are frequently necessary to diagnose AC joint subluxation and dislocation. These are obtained by having the patient hold a 2.3-7 kg (5-15 pound) mass (weight) in the hand or tying this weight to the wrist. If possible, it is beneficial to view both AC joints on a single film. This allows comparison of the two joints, permitting the radiologist to observe the distance between the coracoid process and clavicle on both sides.
Technical factors
Positioning for an AP projection of the AC joint
Evaluation criteria for an AC joint radiograph
AuntMinnie.com contributing writer February 18, 2003 Related Reading Getting the most from shoulder positioning, December 24, 2002 The bends and flexures of forearm and elbow x-ray positioning, November 21, 2002 The twists and turns of hand and wrist x-ray positioning, October 15, 2002 Digit imaging requires diligent positioning, September 17, 2002 Patient positioning techniques for a lower gastrointestinal series, June 27, 2002 Copyright © 2003 AuntMinnie.com How many pounds of weight should be affixed to each wrist for the AP projection of the AC joint?Shoulder Girdle/Clavicle. What Cr angle is required for the AP axial projection Alexander method for AC joints?In the Alexander method (AP axial projection), which is superior in delineating abnormalities of AC joint, the CR is directed to the coracoid process at a cephalic angle of 15°. This angulation projects the AC joint above the acromion.
How should the central ray be angled for the AP projection of the AC joints?Central ray: The central ray should be directed to the scapulohumeral joint perpendicular to the image receptor. For an AP Axial, a cephalic angle of 35 degrees.
How many degrees is the body rotated for the AP oblique projection of the shoulder joint?The AP oblique Grashey view is obtained with the patient rotated 35-45 degrees and his or her back (scapular body) up against the imaging detector.
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