Which two cervical vertebrae account for the greatest amount of axial rotation?

Which two cervical vertebrae account for the greatest amount of axial rotation?

• A. C1 & C2
• B. C2 & C3
• C. C5 & C6
• D. C4 & C5

Answer: (A)

Rotation of the neck is dominated by the joint between the first two cervical vertebrae. The atlas (the first cervical vertebra) sits in a ring around the axis (the second cervical vertebra) whose upward project is the dens. When you turn your head, C1 pivots around the dens of C2, making this atlantoaxial joint the primary site of axial rotation. The ligaments and the way the facets are oriented at this level set up a pivot that enables a large amount of rotation, roughly half of the cervical rotation occurs here. The lower cervical joints (below C2) mainly allow flexion and extension with only limited rotation, so they contribute far less to axial rotation.

Rotation of the neck is dominated by the joint between the first two cervical vertebrae. The atlas (the first cervical vertebra) sits in a ring around the axis (the second cervical vertebra) whose upward project is the dens. When you turn your head, C1 pivots around the dens of C2, making this atlantoaxial joint the primary site of axial rotation. The ligaments and the way the facets are oriented at this level set up a pivot that enables a large amount of rotation, roughly half of the cervical rotation occurs here. The lower cervical joints (below C2) mainly allow flexion and extension with only limited rotation, so they contribute far less to axial rotation.