Scapula Lateral is a radiography positioning projection of the Upper Extremity. Erect anterior or posterior oblique, rotated until the scapular body is lateral. CR perpendicular to IR. SID 40". The centering point is located mid-vertebral (medial) border of the scapula, with the body rotated until the scapula is in profile. The central ray is perpendicular to the IR, to the mid-vertebral border, rotated until the scapular body is lateral (the degree varies with arm position). Image-quality criteria include scapular body shown in profile without foreshortening, humerus not superimposed on the area of interest. A sample technique is 85 kVp with DR 8 or CR 14 mAs, at an SID of 40 inches (102 cm).
Anatomy demonstrated
- Scapular body in profile.
- Acromion process, seen through the humeral head.
- Coracoid process.
- Inferior angle.
- Vertebral border of scapula.
Patient preparation
- WARNING: with shoulder trauma, do not attempt to rotate the arm if a fracture or dislocation is suspected; leave the affected arm as presented (Bontrager). Merrill's: a trauma patient can be done in the LPO or RPO position.
- Verify patient identity using two identifiers.
- Remove watches, bracelets, and radiopaque items from shoulder.
- Position patient erect facing the IR in an anterior oblique, affected scapula against the IR; rotate until a line from the superior angle to the AC joint is perpendicular to the IR (about 45-60 degrees).
- For the body, have the patient reach across the chest and grasp the opposite shoulder; for the acromion and coracoid, place the arm behind the lower back or let it hang at the side.
- Suspend respiration during the exposure.
Position & centering point
Mid-vertebral (medial) border of the scapula, with the body rotated until the scapula is in profile.
Central ray
Perpendicular to the IR, to the mid-vertebral border, rotated until the scapular body is lateral (the degree varies with arm position).
Exposure / technique
- kVp
- 85
- mAs
- DR 8 / CR 14
- SID
- 40" (102 cm)
- Notes
- Erect technique. Body rotated about 45 degrees with the arm across the chest, about 60 degrees with the arm behind the back or at the side. Sample technique: DR 8 / CR 14 mAs at 85 kVp, 40 in SID, for a 24 cm part. Adjust for your equipment.
kVp and mAs are sample values. Use caution when applying them in your department.
Image-quality criteria
- Scapular body shown in profile without foreshortening.
- Humerus not superimposed on the area of interest.
- Bony borders of the acromion and coracoid seen through the humeral head.
- Scapular body free of rib superimposition.
- Vertebral and lateral borders directly superimposed.
- Collimation: closely to the scapula (Bontrager); 1.5 inches above the shoulder, 1 inch beyond the lateral shadow (Merrill's).
Common errors
- 1 Insufficient rotation fails to show scapula in true profile.
- 2 Vertebral and lateral borders not directly superimposed: adjust the body rotation.
- 3 Rib superimposition obscures scapular detail.
- 4 Humerus left over the area of interest: arm position depends on the scapular part shown.
- 5 CR not at the mid-vertebral border of the scapula.
Clinical indications
- Scapular body fracture evaluation in profile.
- Scapular spine fracture or displacement assessment.