LATERAL PROXIMAL HUMERUS | AP INTERNAL ROTATION SHOULDER
Warning: Do not rotate arm if fracture or dislocation is suspected.
Pathology Demonstrated:
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| The posterior aspect of the hand placed against the hip will position the humerus in internal rotation ..see external rotation |
- Fracture and/or dislocations of the proximal humerus and the shoulder girdle may demonstrate calcium deposits in the muscles, tendons, or bursal structures. Some pathology, such as osteoporosis, osteoarthritis, and bony tumors, also may be evident.
Technical Factors:
- IR size- 24 x 30 cm (10 x 12 inches), crosswise (or lengthwise to demonstrate entire humerus in injury includes proximal half of humerus)
- Moving or stationary grid
- 70+- 5 kV range
- mAs 6
Shielding:
- Shield pelvic area.
Patient Position:
- Perform radiograph with the patient in an erect or supine position.(The erect position is usually less painful for patient, if condition allows.) Rotate body toward affected side, if necessary, to place shoulder in contact with IR or tabletop.
Part Position:
- Position patient to center scapulohumeral joint to center or IR.
- Adduct extended arm slighly; then internally rotate arm (pronate hand) until epicondyles of distal humerus are perpendicular to IR.
Central Ray:
- CR perpendicular to IR, directed to 1 inch (2.5 cm) inferior to coracoid process
- Minimum SID of 40 inches (100cm)
Collimation:
- Collimate on four sides, with lateral and upper borders adjusted to soft tissue margins.
Respiration:
- Suspend respiration during exposure.
Radiographic Criteria for AP Internal Rotation Shoulder
Structure Shown:
- Lateral view of proximal humerus and lateral two-thirds of the clavicle and upper scapula are demonstrated, including the relationship of the humeral head to the glenoid cavity.
Position:
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| AP View Shoulder | Internal Rotation: Greater Tubercle (arrow) | Lesser Tubercle in profile (arrowhead). |
- Full internal rotation position is evidenced by the lesser tubercle visualized in full profile on the medial aspect of the humeral head.
- An outline of the greater tubercle should be visualized superimposed over the hemeral head.
Collimation and CR:
- Collimation should be visible on four sides to area of affected shoulder.
- CR and center of collimation field should be at scapulohumeral joint.
Exposure Criteria:
- Optimal density and contrast with no motion will demonstrate clear, sharp bony trabecular markings with soft tissue detail visible for possible calcium deposits.
