C1 Vertebrae (Atlas)

Authors

Affiliations

Nate Yomogida, B.S., SPT

Doctor of Physical Therapy

B.S. in Kinesiology

Chloë Kerstein, B.S., SPT

Doctor of Physical Therapy

B.A. in Neuroscience

Landmarks

Transverse process

Palpation

C1 Transverse process

To palpate the Transverse process of C1

• Locate the angle of the mandible on the lateral aspect of the jawbone, it should feel “sharp”¹.
• Move posteriorly from the angle of the mandible and you should feel the bony prominence of the C1 transverse process¹.
• C1 TP lies between the angle of the mandible and the mastoid process¹.

Caution

Palpate the C1 transverse process gently since this area may be quite tender¹.

Dysfunction

During a violent forced extension, the posterior arch of the atlas (C1) can be caught between the occipital bone and the posterior arch of the axis (C2) resulting in a “nutcracker” mechanism which fractures the atlas².

References

1.

Finando D, Finando SJ, Finando D. Trigger Point Therapy for Myofascial Pain: The Practice of Informed Touch. Healing Arts Press; 2005.

2.

Jones B. B Project Foundations. b Project; 2025.