During goniometric measurement, the stationary arm is aligned parallel to an imaginary line between the acromial processes. This setup assesses which motion?

• A. Flexion of the cervical spine
• B. Lateral flexion of the cervical spine
• C. Rotation of the cervical spine
• D. Rotation of the thoracic and lumbar spines

Answer: (C)

In goniometry, you align the stationary arm to a fixed reference that stabilizes the part you’re not measuring so the read reflects only the desired motion. Aligning the stationary arm parallel to the line between the acromial processes places that reference across the shoulders, which stabilizes the thorax. When the head turns left or right, the movement occurring is rotation of the cervical spine in the horizontal plane, and the moving arm tracks that rotation relative to the fixed trunk reference. This setup isolates cervical rotation, whereas flexion/extension use a different alignment and rotation of the thoracic/lumbar spine would involve the trunk rather than the neck.