Dogs love to play and run outside. In many cases, it’s all fun and games, but in some, injuries might come. It can appear as limping in the back leg, an acquired reluctance to jump, or even obvious struggling to get up. 

Many might think it’s a hip, knee, or leg problem. In some cases, it’s iliopsoas myositis in dogs. The iliopsoas muscle group plays a key role in hip flexion and core stability. This means that it’s used every time your dog runs, climbs stairs, and stands up from the ground. 

When this muscle becomes strained, inflamed, or injured, your dog may show subtle changes in gait or avoid certain movements entirely. This condition affects a deep muscle in the dog’s hip and lower back area.

Because the iliopsas muscle is situated deep within the dog’s body, injuries can be tricky to diagnose. In this guide, we’ll break down everything you need to know about iliopsoas myositis in dogs, from the muscle itself to the treatment options. 

What Is the Iliopsoas Muscle in Dogs?

The iliopsoas is a combination of two muscles: the psoas major and iliacus. It’s located in the area where the spine meets the pelvis, connecting the spine and femur. 

Because of its strategic location, the iliopsoas is also a major player in hip flexion, the movement that lifts the dog’s hind leg forward. This also helps stabilize the lower spine and pelvis during motion. 

The iliopsas’ position makes it vulnerable to strain injuries and overuse, since it’s always engaged whenever your dog walks, runs, jumps, or climbs stairs. 

In healthy dogs, the iliopsoas works silently in the background, powering everyday movements and providing stability. In inflamed and strained ones, dogs may feel a sharp pain.

What Causes Iliopsoas Myositis in Dogs?

Iliopsoas myositis in dogs can develop from both sudden injuries and gradual overuse. Here are the common ones: 

Acute Trauma or Overstretching

One of the most common causes of iliopsas myositis in dogs is the forceful stretch of the iliopsas muscle. This can happen whenever a dog slips on a slippery floor, missteps while running, jumping, and landing awkwardly, or changes directions at high speed.

The abrupt and sudden movements can overstretch the dog’s muscle fibers, damaging the tendon where it attaches to the femur.

Chronic Overuse

Dogs that participate in high-intensity activities such as agility, flyball, and other canine sports can strain their iliopsoas muscles due to overuse. Over time, this can result in micro-tears in the muscle fibers, which lead to inflammation and chronic pain. 

Concurrent Orthopedic Conditions

If your dog has another orthopedic problem, such as hip dysplasia and cruciate ligament injuries, it may have an uneven movement pattern. This can apply additional strain on the iliopsoas muscle group, leading to strain and injury. 

Breed and Activity Level

While any dog can be at risk of iliopsoas myositis, sporting breeds and working dogs are at a higher risk because of their activity level and physical demands. Border Collies are a great example. 

What Are the Signs of Iliopsoas Myositis in Dogs?

The symptoms of canine iliopsoas myositis can often mimic other orthopedic issues. They can start off as subtle changes but can progress to become noticeable ones when the injury worsens. This includes:

• Hind Limb Lameness. Dogs with iliopsoas injury often show a limp in one of their back legs. The limping can be more obvious after exercise or play. 

• Difficulty Getting Up. Some dogs can be seen having difficulty getting up from their resting posture. This is because the muscle is heavily involved in hip flexion. 

• Altered Gait. Affected dogs can appear to have an altered walking style, one that is stiff and painful. You might notice your dog taking shorter steps with the affected hind leg. 

• Reluctance to Jump or Climb. Some dogs also lessen their jumping and climbing movements due to the pain they feel whenever they use their hind legs. 

• Sensitivity to Touch. Gently pressing or massaging the area can cause your dog to flinch or pull the leg away. 

• Decreased Physical Activity. Dogs affected by iliopsoas myositis can lose speed, have trouble with jumping, or become reluctant to run. 

• Postural Changes. Some dogs may arch their back or shift weight forward as a way to alleviate the pain they feel.