This TBT (Tucker BioKinetic Technique) Checkup is for the Sacroiliac (SI) joint. You can do this on your horse.

Be sure to do both sides and compare. Unfortunately, sometimes both are "stuck". So be sure to compare with other horses as well.

If your horse has a sacroiliac problem, check out Reverse the Diagnosis ebook for underlying causes of SI issues in horses: https://www.tuckerbiokinetic.com/rtdbook