What is the normal range for shoulder abduction?

What is the normal range for shoulder abduction?

• A. 0-180°
• B. 0-120°
• C. 0-90°
• D. 0-70°

Answer: (A)

Shoulder abduction measures the full arc of motion from the arm at the side up to the arm raised overhead, and it involves the whole shoulder complex, not just the main joint. As you lift the arm in the frontal plane, the glenohumeral joint contributes about 90 degrees, and the scapulothoracic mechanism must upwardly rotate to allow the full range, adding roughly another 60 degrees. Together, this gives about 180 degrees of motion. That’s why the normal range is 0 to 180 degrees. The other options underestimate the full arc because they reflect only part of the movement or limit the motion to the glenohumeral joint alone.

Shoulder abduction measures the full arc of motion from the arm at the side up to the arm raised overhead, and it involves the whole shoulder complex, not just the main joint. As you lift the arm in the frontal plane, the glenohumeral joint contributes about 90 degrees, and the scapulothoracic mechanism must upwardly rotate to allow the full range, adding roughly another 60 degrees. Together, this gives about 180 degrees of motion. That’s why the normal range is 0 to 180 degrees. The other options underestimate the full arc because they reflect only part of the movement or limit the motion to the glenohumeral joint alone.