Final answer:
The question about the degrees of scapular upward rotation during the first 30° of arm elevation has an incorrect set of options. In typical biomechanics, about 10° of scapular upward rotation is involved in the first 30° of arm elevation.
Step-by-step explanation:
The question pertains to the biomechanics of the shoulder complex during arm elevation. Specifically, it asks about the contribution of scapular upward rotation when the arm is elevated by 30°. The correct answer is not listed in the options provided by the student. In reality, the first 30° of arm elevation typically involves about 10° of scapular upward rotation. This means that none of the options A) 30°, B) 45°, C) 60°, or D) 90° are correct. Human movement and particularly scapulothoracic motion is complex, and the proportion of scapular rotation can vary between individuals. Nevertheless, the scapula generally starts contributing to arm elevation after the first 30 degrees of elevation.