Internal rotation is defined as which of the following?

• A. Rotation toward the middle of the body
• B. Rotation away from the middle of the body
• C. Rotation around the long axis of the limb
• D. Rotation with flexion

Answer: (A)

Internal rotation is about turning a limb toward the body's midline. This directional sense is what defines it: when the limb rotates inward so its front faces move toward the center of the body, that’s internal rotation. That’s why the best choice states rotation toward the middle of the body. Rotating away from the midline is external rotation, which is not what’s being described here. The idea of rotating around the long axis describes the axis of rotation, which is involved in internal/external rotation, but it doesn’t specify the inward direction. Rotation with flexion mixes two different ideas and isn’t the defining feature of internal rotation.