A Real Pain In The Butt

By Ian Nurse, DC

This past month, as the Boston Marathon training cycle came to a close, more and more runners started coming into my office complaining of the same thing: “So I have this dull ache in my butt! I think it’s my piriformis.” With this sudden spike of a particular injury in mind, I will attempt to answer the following questions: why is everybody talking about the piriformis and where the heck is it?

For such a small muscle, the piriformis seems to get a lot of attention. It does play an important role as a hip stabilizer and an external rotator (bringing your leg out and back), but it doesn’t act alone. There are three other external rotators and stabilizers of the hip that play an equally significant role.

So why does this one little muscle get a whole syndrome named after it? The answer revolves around the piriformis’ proximity to another extremely important structure, the sciatic nerve. The piriformis muscle and sciatic nerve are close neighbors that even demonstrate various positioning throughout the population. For the majority of the population, the sciatic nerve lies directly beneath the lower edge of the piriformis; others demonstrate a split sciatic nerve lying above and below the piriformis; another small group actually have their sciatic nerves bisect the muscle itself. That said, all four deep external rotators, as well as the gluteus medius muscle, are positioned close enough to the sciatic to cause irritation. Perhaps a more appropriate name might be “deep external rotator syndrome?”

Traditionally, piriformis syndrome is used to describe a condition in which tension within only the piriformis muscle produces entrapment and irritation of sciatic nerve. This entrapment can be caused by numerous soft tissue factors including an excess of scar tissue surrounding the nerve or a muscle imbalance. As the sciatic nerve is one of the largest nerves in the body, comprised of nerve roots from L4-S3, if it becomes entrapped, one can feel a variety of symptoms. Typically, a patient complains of a deep ache in the hip with pain and/or paresthesia (abnormal tingling or sensation) traveling down the back of the thigh and into the calf and foot. Symptoms are often exacerbated when the patient performs squats or stands from a seated position. Clinically, patients notice symptoms more with sitting and during car rides. Repetitive activities such as walking, running, and cycling can become quite uncomfortable as tension over the sciatic builds.

While the positioning of the anatomy plays an important role, there are many avoidable risk factors that contribute to developing this syndrome. As the main hip external rotators are the gluteus maximus and gluteus medius, weakness and imbalance within these muscles impede on proper function of the deep hip rotators, thus, causing tension. Wearing improper footwear, running on banked surfaces or slippery surfaces (think of all the snow this past winter) and sitting all day (especially if you have a wallet in your back pocket) are also common causes. Pregnancy, and the resulting relaxation of the pelvic bowl ligaments, is a potential cause, as the deep rotators must now pick up the slack for the ligaments.

As runners, we need to pay attention to the little things within our training that can cause these muscles to get irritated. Replacing your shoes before they become too worn out, avoiding banked surfaces, and strengthening of the hip girdle muscles can make a big difference in avoiding this condition in the first place.

As one can see, while small, these muscles can cause big problems. Thankfully, the most effective form of treatment is a conservative one that involves muscle therapy, stretching, and strengthening. The Myrtle Routine created by Coach Jay Johnson is an important supplement to training that can be performed a few times a week to help avoid any muscle imbalance. In addition, a tennis or lacrosse ball can be a simple and inexpensive means of trigger point therapy helping to break up scar tissue deep in the glute and relax the musculature releasing tension on the sciatic.

While “external rotator syndrome” is, both literally and figuratively, a pain in the butt, when treated correctly, it is not an injury that has to stop you from doing the activities that you love.

This is an excerpt from the latest issue of Level Renner (Issue 14, May/Jun 2013). As always, it’s free, so download it here. Sign up for your free subscription (in the sidebar) and you’ll be alerted each time we publish. Ian Nurse is not only a chiropractor but also a real fast runner. See our Boston Marathon coverage to see how he did.