Recommended radiographs for the shoulder trauma series include the following:
• A true anteroposterior view in the plane of the scapula with the arm in internal and external rotation
• An axillary lateral view. If an axillary radiograph cannot be obtained, one of the following views must be obtained:
• A scapulolateral view
• One of the modified axillary views
• A CT scan
—Radiographs of the injured shoulder in two planes (anteroposterior and axillary lateral or scapular lateral) are absolutely essential to evaluation of an acutely injured shoulder
___True Anteroposterior Views ___
Because the scapula lies on the posterolateral aspect of the thoracic cage, the true anteroposterior view of the glenohumeral joint is obtained by angling the x-ray beam 45 degrees from medial to lateral.The advantage of the true anteroposterior views of the scapula over traditional anteroposterior views in the plane of the thorax is that the x-ray demonstrates the glenoid in profile rather than obliquely and, in the normal shoulder, clearly separates the glenoid from the humeral head . In the true anteroposterior x-ray, the coracoid process overlaps the glenohumeral joint. If the true anteroposterior x-ray demonstrates the humeral head to be overlapping with the glenoid, the glenohumeral joint is dislocated either anteriorly or posteriorly.
Axillary Lateral View
Initially described by Lawrence in 1915, the axillary lateral x-ray can be taken with the patient supine or erect. Ideally, the arm is positioned in 70 to 90 degrees of abduction. The x-ray beam is directed into the axilla from inferior to superior, and the x-ray cassette is placed superior to the patient’s shoulder.Axillary lateral x-rays provide excellent visualization of the glenoid and the humeral head and clearly delineate the spatial relationship of the two structures. Loss of glenohumeral cartilage is clearly revealed when the joint space between the glenoid and the humeral head is decreased or absent. Dislocations are easily identified, as are compression fractures of the humeral head and large fractures of the anterior or posterior glenoid rim . Some fractures of the coracoid and the acromion and the spatial relationship of the acromioclavicular joint can also be seen on this view.
The scapulolateral view is sometimes known as the transscapular, the tangential lateral, or theY lateral.
A lateral projection of the scapula forms a Y shape . The upper arms of the Y are formed by the coracoid process anteriorly and by the scapular spine posteriorly. The vertical portion of the Y is formed by the body of the scapula. At the intersection of the three limbs of the Y lies the glenoid fossa. In the normal shoulder, the humeral head is located overlapping the glenoid fossa . This view is particularly helpful in determining the anterior or posterior relationship of the humeral head to the glenoid fossa.
_Modified Axillary Views
1-Velpeau Axillary Lateral View:
Bloom and Obata’s modification of the axillary lateral x-ray of the shoulder is known as the Velpeau axillary lateral because it was intended to be taken with the acutely injured shoulder still in a sling without abduction.
With the Velpeau bandage or shoulder sling in place, the patient stands or sits at the end of the x-ray table and leans backwards 20 to 30 degrees over the table.
The x-ray cassette is placed on the table directly beneath the shoulder, and the x-ray machine is placed directly over the shoulder so that the beam passes vertically from superior to inferior, through the shoulder joint onto the cassette . On this view, the humeral shaft appears foreshortened and the glenohumeral joint appears magnified, but otherwise, it demonstrates the relationship of the head of the humerus to the scapula.
2-Apical Oblique View
Garth, Slappey, and Ochs have described an apical oblique projection that reliably demonstrates the pathology of the glenohumeral joint. The patient may be seated or in a supine position, and the arm may remain in a sling. The x-ray cassette is placed posteriorly, parallel to the spine of the scapula. The x-ray beam is directed through the glenohumeral joint toward the cassette at an angle of 45 degrees to the plane of the thorax and is also tipped 45 degrees caudally.
The resultant x-ray demonstrates the relationship of the humeral head to the glenoid and therefore identifies the presence and direction of glenohumeral dislocations and subluxations. This view clearly defines the anteroinferior and posterosuperior rims of the glenoid and is useful for detecting calcifications or fractures at the glenoid rim . Posterolateral and anterior humeral head compression fractures are also revealed by this view.Kornguth and Salazar reported that this technique is excellent for diagnosis in the acute setting.
3-Stripp Axial Lateral View: The Stripp axial view, described by Horsfield,17 is similar to the Velpeau axillary lateral view, except that the beam passes from inferior to superior and the x-ray cassette is positioned above the shoulder.
4-Trauma Axillary Lateral View
Another modification of the axillary lateral view has been described by Teitge and Ciullo. The advantage of this view over the Velpeau and Stripp views is that it can be taken while the patient is supine, as is often necessary in patients with multiple trauma. This view can be taken while the injured shoulder is still immobilized in a shoulder-immobilizer dressing. To obtain this view, the patient is supine on the x-ray table, and the involved arm is supported in 20 degrees of flexion by placing radiolucent material under the elbow. The x-ray beam is directed up through the axilla to a cassette propped up against the superior aspect of the shoulder. This view defines the relationship of the humeral head to the glenoid fossa.