Finding the Right Spot To Feel The Transverse Process
Doctors and therapists treating the thoracic spine (middle of the back) have some special challenges. The anatomy of the thoracic spine is different from the cervical spine (neck) and the lumbar spine (low back). The bones of the thoracic spine are the transition units from cervical to lumbar spine.

In this study, physical therapists test a new model for finding the transverse processes (TP) of the thoracic spine. The TP is a bony extension out to the side of the vertebral bone. It connects to the rib on either side of the vertebrae. Restoring normal alignment and motion at this connection is important for some patients with shoulder, neck, or back pain.

But finding the exact spot of the TP can be difficult. It's not close to the surface of the skin. Some examiners use the spinous process (SP) to help them find the TP. But the shape and direction of the SP changes from the top of the bottom of the thoracic spine. The spinous process is the bump you feel along the middle of your back. Using this landmark to locate the TP may not be reliable.

To find the best way to locate the TPs, researchers dissected 15 cadavers. They removed the soft tissues over the TPs and SPs. They inserted pins into the SPs and TPs of each thoracic vertebra. Then they used a digital caliper to measure the distances between these two points. They took into consideration how far apart the fingers have to be to feel contact points.

The authors report that if you find the SP and palpate (feel) just to the side of it, you'll be on the TP of the vertebra one level above. This holds true throughout the thoracic spine.

This model replaces the previously used Rule of Threes model. The old model used the SPs to find the TPs. This method tried to adjust for the change in angle of the SP from vertebra to vertebra. The new model shows this is not necessary. However, this new model may not always apply to the last two thoracic vertebrae (T11 and T12) because of how much they vary in position from person to person.
Michael A. Greelhoed, PT, DPT, OCS, MTC, et al. A New Model to Facilitate Palpation of the Level of the Thoracic Processes of the Thoracic Spine. In Journal of Orthopaedic & Sports Physical Therapy. November 2006. Vol. 36. No. 11. Pp. 876-881.