The Tailbone

Pain in the lower back can often be described by clients as a pain in their tailbone. Typically, when clinicians hear this, we think of the coccyx, the last segment of the spine. However, clients might point to their sacrum, the much larger triangular shaped bone just below the lumbar spine. The two regions are in direct contact and influence each other to a great degree. As practitioners we should be specific about which region we want to address. These two anatomical regions differ in their construction and that affects how we make decisions regarding their programming/movement prescriptions.

The coccyx is the last segment of the spine, consisting of four vertebrae that fuse across the lifespan. It attaches directly to the last sacral vertebra and has some interesting muscular attachments, namely the gluteus maximus. The lower portion of glute max attaches directly to the coccyx and if that musculature is having a difficult time turning off or is repeatedly activated it can compress the ipsilateral coccyx. Compression to a sufficient degree will reduce circulation and pain usually ensues shortly thereafter.

If we are suspicious that the client is describing more sacral pain, this level is higher in the spine, and a different aspect of glute max is involved. The higher we travel along the sacrum the greater the proportion of glute max we recruit. This muscle is often traditionally described as one big muscle, but as dissections improve it is starting to be appreciated as multiple. The larger portion spans the sacro-iliac joint, aka the SI joint, and just like with the lower portion can compress this joint if overutilized.

When considering how to train or treat clients with these issues we should be specific in which area we are looking to change and program exercises that alter mechanics at the appropriate region. For instance, if we want to alter mechanics at the coccyx we could consider a deep squat, most likely on slant boards, to promote expansion here. Whereas if the base of the sacrum is the area primarily affected, then a box squat may be the more effective means of decompression.

When clients mention pain in their tailbone, we must first identify what they mean exactly by the tailbone, as this is often confused. Once we have confidence in where the issue has arisen, we can prescribe exercises accordingly. Deciding where we want to alter mechanics influences how we prescribe movement. We can bias particular regions via different exercises, and that requires thoughtful programming.

Austin Ulrich, Physical Therapist