POSTERIOR OBLIQUE POSITION - GLENOID CAVITY: SHOULDER (NONTRAUMA)

GRASHEY METHOD

Pathology Demonstrated:

• Fractures and/or dislocation of the proximal humerus and fractures of the glenoid labrum or brim are demonstrated; may demonstrate a Bankart lesion, erosion of glenoid rim, and the integrity of the scapulohumeral joint; also may demonstrate certain pathologies, such as osteoporosis and osteoarthritis.

Technical Factor:

• IR size - 18 x 24 cm (8 x 10 inches), crosswise
• Moving or stationary grid
• 75 +- 5 kV range
• mAs 7

Shielding:

Upright AP oblique glenoid cavity: Grashey method.

• Place gonadal shielding over 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 conditions allows.)

Part Position:

• Rotate body 35 to 45 degree toward affected side.
• If the radiograph is performed with the patient in supine position, place supports under elevated shoulder and hip to maintain this position.
• Center mid-scapulohumeral joint to CR and to center of IR.
• Adjust cassette so that top of IR is about 2 inches (5 cm) from lateral border of humerus.
• Abduct arm slightly with arm in neutral rotation.

Recumbent AP oblique glenoid cavity: Grashey method

Central Ray:

• CR perpendicular to IR, centered to scapulohumeral joint, which is approximately 2 inches (5cm) inferior and medial form the superolateral border of shoulder.
• Minimum SID of 40 inches (100cm)

Collimation:

• Collimate so upper and lateral borders of the field are to the soft tissue margins.

Respiration:

• Suspend respiration during exposure.

Note:

• The degree of rotation varies depending on how flat or round the shoulder of the patient are:
• Having a rounded or curved shoulder and back requires more rotation to place the body of the scapula parallel to the IR.

Radiographic Criteria:

Structures Shown:

AP oblique glenoid cavity: Grashey method

• Glenoid cavity should be seen in profile without superimposition of humeral head.

Position:

• The scapulohumeral joint space should be open.
• Anterior and posterior rims of glenoid cavity are superimposed.

Collimation and CR:

• Collimation should be visible on four sides to area of affected shoulder.



AP oblique glenoid cavity: Grashey method
Showing moderate deterioration of the scapulohumeral joint

• CR and center of the collimation field should be at the mid-glenohumeral joint.

Exposure Criteria:

• Optimal density and contrast with no motion will visualize soft tissue margins and clear, sharp bony trabecular markings.
• Soft tissue detail of the joint space and axilla should be visualized.