Shoulder Scapular Y is a radiography positioning projection of the Upper Extremity. Erect 45-60 degree anterior oblique, arm hanging at the side. SID 40". The centering point is located the intersection of the scapular body, coracoid, and acromion (the y junction), arm at the side.. The central ray is perpendicular to the scapular y formed by the scapular body, spine, and acromion.. Image-quality criteria include scapular y clearly formed by scapular body, spine, and acromion., humeral head centered at the y junction.. Standard exposure ranges from 70 to 80 kVp, 6 to 12 mAs, at an SID of 40 inches (102 cm).
Anatomy demonstrated
- Scapular body forming the lower arm of the Y.
- Scapular spine forming the transverse arm of the Y.
- Acromion process at the superior junction.
- Coracoid process visible.
- Humeral head at the Y intersection.
- Proximal humerus in profile.
Patient preparation
- Verify patient identity using two identifiers.
- Remove watches, bracelets, and radiopaque items from shoulder.
- Position patient erect in a 45-60 degree anterior oblique.
- Let the arm hang at the side, abducted slightly if possible; do not attempt to rotate it.
- Keep scapula and humerus aligned in the scapular plane.
Position & centering point
The intersection of the scapular body, coracoid, and acromion (the Y junction), arm at the side.
Central ray
Perpendicular to the scapular Y formed by the scapular body, spine, and acromion.
Exposure / technique
- kVp
- 70–80
- mAs
- 6–12
- SID
- 40" (102 cm)
- Notes
- Erect technique. The arm hangs at the side and may be abducted slightly so the humerus does not overlie the ribs; never attempt to rotate it. Breathing suspended.
Image-quality criteria
- Scapular Y clearly formed by scapular body, spine, and acromion.
- Humeral head centered at the Y junction.
- Acromion process visible at the superior arm of the Y.
- Coracoid and acromion form the upper arms of the Y, the scapular body the stem.
- Scapular body and spine superimposed.
- Collimation: 3 inches on all sides of the shoulder.
Common errors / ARRT traps
- 1 Insufficient body obliquity skews the Y and superimposes the humeral head.
- 2 Insufficient scapular Y formation from rotation or arm position.
- 3 Patient breathing motion blurs the image during exposure.
- 4 Off-centered CR misses the Y junction.
- 5 Body position too lateral or oblique distorts the Y symmetry.
Clinical indications
- Anterior or posterior humeral head dislocation evaluation.
- Shoulder trauma follow-up with suspected dislocation.
- Proximal humeral fracture assessment.
- Post-reduction shoulder dislocation check.
Aligned to the current ARRT Radiography Content Specifications.