National Physical Therapy Examination (NPTE) Practice Exam

When a patient elevates their arm past 120 degrees of elevation, what muscles primarily facilitate upward rotation of the scapula?

1. Lower trapezius and serratus anterior muscles

2. Lower trapezius and middle trapezius muscles

3. Upper trapezius and lower trapezius muscles

4. Serratus anterior and upper trapezius muscles

The correct answer is: Lower trapezius and serratus anterior muscles

The muscles that primarily facilitate upward rotation of the scapula during arm elevation beyond 120 degrees are the lower trapezius and the serratus anterior. The serratus anterior plays a crucial role in the protraction and upward rotation of the scapula. Its contractions allow the scapula to move laterally and upward as the arm elevates. This action is particularly important for the overall function of the shoulder girdle, ensuring that the glenohumeral joint remains stable during overhead movements. The lower trapezius also contributes significantly to this upward rotation. When the arm is elevated, the lower trapezius is activated to assist in pulling the medial border of the scapula toward the spine, working in conjunction with the serratus anterior to achieve the necessary motion. Through the coordinated action of these two muscles, the scapula can move effectively in upward rotation, which is essential for achieving full range of motion in shoulder elevation beyond 120 degrees.