Which position is used to test shoulder internal rotation under gravity-minimized conditions?

Which position is used to test shoulder internal rotation under gravity-minimized conditions?

• A. Prone with shoulder and elbow extended off the edge of the table; head rotated to the same side.
• B. Prone with tested arm hanging freely over the edge of the table; head rotated away.
• C. Seated with arm abducted 60 degrees.
• D. Supine with arm abducted and extended.

Answer: (A)

The test uses a gravity-eliminated setup to isolate the shoulder internal rotators so their strength is measured without the extra influence of the limb’s weight. Placing the patient prone with the shoulder and elbow extended off the edge of the table positions the arm in a way that minimizes the gravitational torque on the shoulder joint, while allowing the examiner to apply resistance to internal rotation in a controlled, isolated manner. Turning the head to the same side helps stabilize the neck and shoulder girdle, reducing compensatory movements that could skew the result. Other positions would introduce more gravitational influence or change the mechanics of the shoulder, making it harder to attribute any movement to the internal rotators alone. For example, positions where the arm is hanging or abducted alter the torque and recruit different muscles, so they’re less suitable for gravity-minimized testing of internal rotation.

The test uses a gravity-eliminated setup to isolate the shoulder internal rotators so their strength is measured without the extra influence of the limb’s weight. Placing the patient prone with the shoulder and elbow extended off the edge of the table positions the arm in a way that minimizes the gravitational torque on the shoulder joint, while allowing the examiner to apply resistance to internal rotation in a controlled, isolated manner. Turning the head to the same side helps stabilize the neck and shoulder girdle, reducing compensatory movements that could skew the result.

Other positions would introduce more gravitational influence or change the mechanics of the shoulder, making it harder to attribute any movement to the internal rotators alone. For example, positions where the arm is hanging or abducted alter the torque and recruit different muscles, so they’re less suitable for gravity-minimized testing of internal rotation.