Napoleon's Sign ( Belly Press ) tests the integrity of which muscle?

• A. Subscapularis
• B. Supraspinatus
• C. Infraspinatus
• D. Teres Minor

Answer: (A)

Napoleon's Sign (Belly Press) directly tests the subscapularis, the shoulder’s main internal rotator and a key stabilizer of the humeral head. In this test, you place the hand on the abdomen with the elbow flexed about 90 degrees and press the palm into the belly. An intact subscapularis lets you generate that internal rotation so the hand stays flat against the abdomen and the elbow remains close to the body, with the scapula stable. If the subscapularis is torn or weakened, maintaining internal rotation is difficult; the shoulder compensates by recruiting other muscles (like the pectoralis major), and the elbow may drift or the palm may fail to stay flush with the abdomen. This compensatory pattern produces a positive sign, indicating subscapularis insufficiency. The other rotator cuff muscles are primarily involved in external rotation or different planes of movement, so their integrity isn’t what this test specifically assesses.