Final answer:
To measure arm motor function, practitioners often check muscle tone and for tremors, while scientists may measure the mass of an arm and its center of mass in a static study using scales and calculating the forces involved.
Step-by-step explanation:
Measuring Arm Motor Function
When studying the motor function of the arm, the assessment typically involves observing and palpating the muscles for abnormalities and assessing muscle tone by moving the arm through its passive range of motion. In a more technical approach, one could measure the mass of the arm and its center of mass to understand the arm's mechanics better. In such an anatomical study, a subject would lie on their back, extend the arm, and two scales would be used to measure the force at the elbow and the hand. By interpreting the readings from the scales and knowing the distances from the shoulder to each scale, the mass of the arm and the center of mass can be calculated. A free body diagram would help in directing the analysis of these measurements.
To measure arm motor function and mass accurately, one might need to change the position of the scale under the hand, or use different measuring methods, such as leveraging biomechanical models or conducting a motor exam which involves checking muscle tone and the presence of tremors in extended positions. Also, factors like centripetal acceleration during dynamic activities can provide additional information about arm movement and function.