TRANSTHORACIC LATERAL PROJECTION: HUMERUS (TRAUMA)

Pathology Demonstrated:

Fracture of the diaphysis of the humeral are demonstrated. An AP with neutral rotation is required in addition to the transthoracic lateral projection.

Technical Factor:

IR size 35 x 43 cm (14 x 17 inches), lengthwise
Moving or stationary grid, vertical, CR to centerline
75+- 5kV range
Minimum of 2 seconds exposure time with breathing technique (between 2 and 4 seconds is desirable)

Shielding:

Patient Position:

Upright transthoracic lateral shoulder

Perform radiograph with the patient in an erect or supine position. (The erect position, which also may be more comfortable for patient, is preferred.) Place patient in lateral position with side of interest closest to IR. With patient supine, place portable grid lines horizontally and center CR to centerline to prevent grid cutoff (insert).

Part Position:

Place affected arm at patient's side in neutral rotation; drop shoulder if possible.
Raise opposite arm and place hand over top of head; elevated shoulder as much as possible to prevent superimposition of affected shoulder.
Center mid-diphysis of affected humerus and center of IR to CR as projected through thorax.
Ensure that thorax is in a true lateral position or has slight anterior rotation of unaffected shoulder to minimize superimposition of humerus by thoracic vertebrae.

Central Ray:

Recumbent transthoracic lateral shoulder

Collimation:
Collimate on four sides to area of interest.

Respiration:

Breathing technique is preferred if patient can cooperate. Patient should be asked to gently breathe short, shallow breaths without moving affected arm or shoulder. (This will allow best visualization of humerus by blurring out ribs and lung structures)

Note:

If patient is in much pain to drop injured arm and shoulder high enough to prevent superimposition of shoulders, angle CR 10 to 15 degrees cephalad.

Radiographic Criteria:

Structure Shown:

Transthoracic lateral

Lateral view of the entire humerus and glenohumeral joint should be visualized through the thorax without superimposition of the opposite humerus.

Position:

The outline of the shaft of the humerus should be clearly visualized anterior to the thoracic vertebrae. The relationship of the humeral head and the glenoid cavity should be demonstrated.

Collimation and CR:

Collimation should be visible on four sides to area of affected hmerus. CR and center of collimation field should be at the mid-diaphysis of the affected humerus.

Exposure Criteria:

Optimal density and contrast will demonstrate the entire outline of the humerus. Overlying ribs and lung markings should appear blurred because of breathing technique, but bony outlines of the humerus should appear sharp, indicating no motion of the arm during the exposure.

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