Excessive upward rotation of the scapula is most likely due to weakness of which muscles?

Excessive upward rotation of the scapula is most likely due to weakness of which muscles?

• A. Rhomboids and Latissimus Dorsi
• B. Serratus anterior
• C. Upper trapezius
• D. Pectoralis minor

Answer: (A)

Excessive upward rotation happens when the muscles that pull the scapula downward and rotate it downward aren’t doing their job, so the upward-rotating muscles dominate. The long-range downward rotators include the rhomboids and latissimus dorsi, which pull the scapula inward, downward, and rotate it downward. If these are weak, that downward pull diminishes, and the scapula tends to rotate upward more than normal during arm movement. Among the options, weakness of the rhomboids and latissimus dorsi removes a key downward-rotating force, making excessive upward rotation the most likely outcome. Serratus anterior, if weak, tends to cause insufficient upward rotation and winging; the upper trapezius mainly contributes to elevation and upward rotation, so weakness would reduce upward rotation rather than cause excess; pectoralis minor is a downward rotator, but its weakness is less likely to produce the observed pattern compared with losing both rhomboids and latissimus dorsi.

Excessive upward rotation happens when the muscles that pull the scapula downward and rotate it downward aren’t doing their job, so the upward-rotating muscles dominate. The long-range downward rotators include the rhomboids and latissimus dorsi, which pull the scapula inward, downward, and rotate it downward. If these are weak, that downward pull diminishes, and the scapula tends to rotate upward more than normal during arm movement. Among the options, weakness of the rhomboids and latissimus dorsi removes a key downward-rotating force, making excessive upward rotation the most likely outcome. Serratus anterior, if weak, tends to cause insufficient upward rotation and winging; the upper trapezius mainly contributes to elevation and upward rotation, so weakness would reduce upward rotation rather than cause excess; pectoralis minor is a downward rotator, but its weakness is less likely to produce the observed pattern compared with losing both rhomboids and latissimus dorsi.