What is the primary motion at C1-C2?

What is the primary motion at C1-C2?

• A. Flexion
• B. Lateral Flexion
• C. Rotation
• D. Extension

Answer: (C)

Rotation is the primary motion at this joint because the atlas (C1) rotates around the dens of the axis (C2). The odontoid process acts as a pivot, so when you turn your head, C1 and the skull rotate on the dens. The transverse ligament holds the dens against the anterior arch of C1, stabilizing this motion. Because of this setup, most cervical rotation occurs here, while flexion-extension and lateral flexion are more limited at this level and occur more at other joints like the atlanto-occipital junction.

Rotation is the primary motion at this joint because the atlas (C1) rotates around the dens of the axis (C2). The odontoid process acts as a pivot, so when you turn your head, C1 and the skull rotate on the dens. The transverse ligament holds the dens against the anterior arch of C1, stabilizing this motion. Because of this setup, most cervical rotation occurs here, while flexion-extension and lateral flexion are more limited at this level and occur more at other joints like the atlanto-occipital junction.