Shoulder AP Oblique, Grashey Method is a radiography positioning projection of the Upper Extremity. Body rotated 35-45 degrees toward the affected side. CR perpendicular to IR. SID 40". The centering point is located glenohumeral joint, about 2 inches medial and 2 inches inferior to the superolateral border of the shoulder, body rotated 35-45 degrees so the scapula is parallel to the IR. The central ray is perpendicular to the IR, centered to the scapulohumeral joint. Image-quality criteria include glenoid cavity in profile, joint space clearly open, glenoid cavity free of superimposition by the humeral head. The SID is 40 inches (102 cm).
Anatomy demonstrated
- Glenoid cavity and fossa in profile.
- Proximal humerus and humeral head.
- Coracoid process projecting anteriorly.
- Scapula.
- Acromion and clavicle.
- Shoulder soft tissues.
Patient preparation
- WARNING: do not rotate the arm if a fracture or dislocation is suspected (both books print this at the AP shoulder; Bontrager files this oblique under nontrauma).
- Verify patient identity using two identifiers.
- Remove watches, bracelets, and radiopaque items from shoulder.
- Position patient erect, posterior shoulder to IR.
- Rotate body 35-45 degrees, affected shoulder toward IR.
- Abduct the arm slightly. Bontrager flexes it in neutral rotation; unless a fracture or dislocation is suspected, Merrill's uses internal rotation with the palm on the abdomen and allows department protocol.
- Suspend respiration during the exposure.
Position & centering point
Glenohumeral joint, about 2 inches medial and 2 inches inferior to the superolateral border of the shoulder, body rotated 35-45 degrees so the scapula is parallel to the IR.
Central ray
Perpendicular to the IR, centered to the scapulohumeral joint.
Exposure / technique
- kVp
- N/A
- mAs
- N/A
- SID
- 40" (102 cm)
- Notes
- Erect technique. Bontrager lists 75 ± 5 kV analog and 80 ± 5 kV digital; neither book's chart prints an mAs for this projection. Body rotation is usually 35-45 degrees, with the goal of placing the scapula parallel to the IR. A rounded shoulder or a recumbent patient needs more, up to 60 degrees recumbent in Merrill's.
Image-quality criteria
- Glenoid cavity in profile, joint space clearly open.
- Glenoid cavity free of superimposition by the humeral head.
- Coracoid process visible projecting anteriorly.
- Anterior and posterior rims of the glenoid superimposed.
- Soft tissue detail of the joint space and axilla visible.
- Collimation: upper and lateral borders at the soft tissue margins (Bontrager); about 8 x 10 inches (Merrill's).
Common errors
- 1 Insufficient rotation fails to open the glenoid cavity properly.
- 2 Too little rotation for a rounded shoulder or recumbent patient: the scapula must be parallel to the IR.
- 3 CR not at the scapulohumeral joint, 2 inches medial and inferior to the superolateral shoulder border.
Clinical indications
- Anterior humeral head dislocation or subluxation.
- Glenoid cavity fracture evaluation.
- Fractures of the glenoid labrum or brim, or a Bankart lesion.
- Glenohumeral joint instability evaluation.