There is a diagnostic procedure that can be used to measure motion of C-1 upon C-2 in relation to the rest of the cervical spine.
The patient is supine with the head and neck flexed mildly upward, taking the neck out of extension. The amount of flexion relates to the amount of thoracic kyphosis. A flat thoracic spine requires less flexion. A "round back" thoracic spine requires more flexion to remove extension.
Positioned at the head end of the table, you first evaluate the patient's cervical rotation to the right with finger contact on the atlas. To do this, place your left hand, face up, under the head of the patient. The third finger grasps the lateral aspect of the right transverse process and exerts posterior tissue pull posteriorly until slack is removed. The patient's head rests in the palm of the left hand. The thumb takes a firm and comfortable contact over the left transverse process. The right hand comfortably assists by being placed under the head and over part of the face on the right side.
Rotate the patient's head and neck to the right to the point of tension, or end point, with the tension and slack being concentrated at C-1. Visually check whether the amount of rotation to the right was achieved with the major contact at C-1 level. Repeat the same rotation procedure with rotation to the left, using the right hand as the contact hand.
The end result is that 99 percent of the time, there will be less rotation to the right and more to the left. You can vary the contact method by placing the contact on the left side of the atlas when turning right or on the right side of the atlas when turning left, maintaining slight flexion. The result is the same. There is more restriction in rotation to the right than left. If you introduce lateral flexion, with or without rotation, there is more resistance to lateral flexion on the left as compared to the right side.
If the C-1 level is adjusted from the left side to correct the rotation and lateral bending restrictions, and the motion is rechecked after adjustment, the restriction would be expected to be removed. This is often the case - or the restrictions could be lessened, but not totally removed.
Excluding malformation and significant pathology, mid- to lower cervical compression restrictions (fixations) can restrict atlas movement in rotation and lateral bending. Remove the mid- to lower cervical compression by manual traction or mechanical traction, and the atlas will automatically assume greater range of motion with the testing procedure. In other words, atlas motion and restriction can be greatly influenced by mid- and lower cervical mechanical disorders. (Think about the recurring upper cervical complaints that recur after upper cervical corrections.)
Regarding patients with lower cervical DJD, you can usually find the same reactions at the atlas contacts. If no fusion is involved, traction to separate the lower cervical joint spaces to loosen them can and usually does result in automatic increase in motion at the upper cervical spine.
The manual method of tractioning the mid- to lower cervical spine is more precise and accurate. While the patient's head is in slight flexion, you can palpate the posterior C-spine, assume vertebral contacts, traction at each level and feel for resistance and separation. Such traction can be done in sets of rhythmic, mild- to moderate-induced pulling pressure.
The bottom line: If you are not already doing so, it would seem prudent to include axial motion palpation as part of your assessment of the cervical spine.
Dr. Joseph Kurnik practices in Torrance, Calif. He is a former columnist and longtime contributor to DC; previous articles are available online at www.dynamicchiropractic.com.