Where is the first segment of the spine with coupled motion?

Where is the first segment of the spine with coupled motion?

• A. C0-C1
• B. C1-C2
• C. C3-C4
• D. C2-C3

Answer: (D)

The first segment with coupled motion is the joint between the second and third cervical vertebrae. At the skull-C1 junction the movement is mainly nodding with little rotation, and at the C1-C2 joint the motion is dominated by rotation with little lateral bending. Once you move to C2-C3, the facet orientation allows rotation to occur together with lateral flexion, so coupled motion first appears there.

The first segment with coupled motion is the joint between the second and third cervical vertebrae. At the skull-C1 junction the movement is mainly nodding with little rotation, and at the C1-C2 joint the motion is dominated by rotation with little lateral bending. Once you move to C2-C3, the facet orientation allows rotation to occur together with lateral flexion, so coupled motion first appears there.