The piriformis syndrome is a common problem in people and is now being recognized as a source of dysfunction and pain in pets. There has been a focus mainly for dogs, but affected cats are now being identified. Pain and dysfunction are experienced by pets limiting their mobility and potentially quality of life depending on severity. It can be misdiagnosed as hip dysplasia or other joint disease meaning that it is easily overlooked as a cause of an abnormal gait or hip area discomfort. Many people experience piriformis syndrome so it is valuable to make some comparisons between humans and pets. 

Humans can experience mild to severe pain or numbness in the buttock area that can extend down the leg into the calf and feet. It is the result of entrapment of the sciatic nerve by the piriformis muscle. There can also be accompanying inflammation. The sciatic nerve emerges from under the piriformis muscle near the hip joint. Trauma or injury to the buttock or hip area is thought to be the trigger in at least 50% of the cases. Runners and cyclists are often affected by over use of the piriformis muscle.

There is an interesting relationship between the piriformis muscle and the sciatic nerve. The sciatic nerve is the largest nerve in the body arising from nerve roots at the end of the spine. It is a nerve with both sensory and motor (muscle) fibers that runs down the leg into the foot. Motor nerves go to muscles of the back of the thigh and all muscles below the knee. Sensory information is carried from areas of the foot to the knee. This anatomy and function of the sciatic nerve is similar between humans and dogs and cats. 

The piriformis muscle is located in the buttock area. It attaches to the sacrum (end of the spine in humans) and the first part of the tail in dogs and cats. Also it has attachments to the sacrotuberous ligament and sacroiliac (SI) joint capsule. These origin attachments become important when identifying factors that contribute to piriformis problems. The opposite end (insertion) of the piriformis attaches to the top of the femur bone at the hip area. Function of the piriformis muscle includes stabilizing the hip, extension motion of the hip and rotation of the femur.

One of the obvious, primary differences between humans and pets is the way they stand – humans walk on two legs and pets walk on four. So the mechanics of motion of the lower back, pelvis, and hip joint are different.

For dogs and cats there are numerous contributors to the piriformis syndrome. These may include over use depending on lifestyle (i.e. agility, working, hiking), misalignment of the SI joint, lumbosacral (LS) instability, trauma, or a combination. Affected pets may have an abnormal gait that can have similarities with hip joint degeneration or cranial cruciate ligament (CCL) disease of the knee.

Piriformis syndrome can be challenging to manage because there are numerous factors like the misalignment issues, muscle pain from chronic spasms, and inflammation in the muscle, tendon, and associated sciatic nerve. Each contributor needs to be identified through a careful evaluation which can include observation of the gait, physical examination with focus on palpation of the affected area, radiographs of the hips and lower back, and ultrasound of the sciatic nerve and piriformis.

Therapy involves management of the contributing factors with the use of multiple integrative techniques including osteopathic manipulation, acupuncture, laser therapy, homeopathy, herbs, nutritional supplements, and appropriate rehabilitation exercises. Addition of pain medications may be needed for severe situations.

If you have concerns about your pet’s mobility and comfort, contact your veterinarian.

Ron Carsten, DVM, PhD, CVA, CCRT was one of the first veterinarians in Colorado to use the integrative approach, has lectured widely to veterinarians, and has been a pioneer in the therapeutic use of food concentrates to manage clinical problems. He is also the founder of Colorado Animal Rescue (CARE). In addition to his Doctor of Veterinary Medicine, he holds a PhD in Cell and Molecular Biology and is a Certified Veterinary Acupuncturist and Certified Canine Rehabilitation Therapist. He practices integrative veterinary medicine in Glenwood Springs. Dr. Carsten is the 2022 Colorado Veterinary Medical Association Distinguished Service Award recipient.