In the inferosuperior axial projection of the shoulder, the arm should be abducted to what degree?

In the inferosuperior axial projection of the shoulder, the arm should be abducted to what degree?

• A. 45°
• B. 90°
• C. 120°
• D. 135°

Answer: (B)

In the inferosuperior axial projection of the shoulder, the arm should be abducted to 90 degrees. This positioning is critical for obtaining the best possible visualization of the shoulder joint and related structures. When the arm is abducted to this degree, it allows the central ray to pass through the axilla (armpit) and exit through the scapula, providing a clear view of the glenohumeral joint and the surrounding bony anatomy.

Abducting the arm to 90 degrees helps to prevent obstructions from the surrounding tissues and enhances contrast, facilitating a more accurate assessment of any potential pathologies or injuries in the shoulder area. This specific angle aligns the humeral head with the image receptor correctly and demonstrates the lateral view of the glenoid cavity, which is essential for comprehensive diagnostic purposes.