I saw a chiropractor and a Physical Therapist for back pain this month. They both did this funky test pressing against my backbone several times. What does this tell them?
You may be describing a test for mobility or movement of the spinal segments. Were you lying face down on a mat or table? If so, then the test is called a posterior-anterior glide or mobility test.
The test is done using the pad of the palm on the little finger side. The examiner applies a gentle "spring-like" pressure down through the spinous process. The vertebrae at several levels are tested up and down the spine. This helps the examiner feel what's normal for you.
The idea is to look for too much or too little motion. Treatment is based on whether the patient needs more or less motion at each level.
Julie M. Fritz, PhD, PT, ATC, et al. Lumbar Spine Segmental Mobility Assessment: An Examination of Validity for Determining Intervention Strategies in Patients with Low Back Pain. In Archives of Physical Medicine and Rehabilitation. September 2005. Vol. 86. No. 9. Pp. 1745-1752.