Dogs with groin or iliopsoas muscle issues are a common source of injury, chronic pain and lameness in a dog’s hind limb. More common than you may think!
WHERE IS THE ILIOPSOAS MUSCLE?
The iliopsoas muscle consists of the fusion of two muscles – the Iliacus and the psoas major.
Hence: ilio+ psoas = iliopsoas.
It is often shortened to “psoas” (pronounced “so-az”).
The iliopsoas is located along the dog’s lower spine and groin area. This muscle also connects to the inside of the dog’s thigh bone.
WHAT DOES IT DO?
The psoas is the master muscle of the lower body. It is a core muscle. It is involved in all lower body movement- jumping, changing directions, laying down, standing up, and forward motion.
1. Flexing the hip
The main function of the psoas is to flex (contract the hip) and externally rotate the hip. Think a male dog urinating on a tree – he brings his leg in (flexing) and lifts it by twisting/rotating his trunk. Because it is a major hip flexor, if it is in spasm, it will cause many of the muscles in the lumbar region to compensate and become painful.
It also helps prepare the body to explode forward or change direction.
Canine athletes such as agility, herding and sporting dogs regularly move at high speeds or bursts of speed. Their body is put into contortions at these high rates of speed causing the iliopsoas to work hard and at odd angles.
The iliopsoas has major functionality and is a common muscle to become either overused or injured. Most injuries occur during extension and external rotation of the leg or flexion (contraction) of the trunk.
2. Flexing the spine
The iliopsoas also plays a part in flexing the lumbar spine, arching the back – think of a dog defecating.
3. Stabilising the hip joint
The iliopsoas stabilises the vertebral column. This helps balance the lower back.
A dog uses these muscles to flex the hip and lower part of the spine. Anytime the lower back and hip have to flex (contract) the psoas is involved.
If the psoas is healthy the lumbar spine rests in a perfect, symmetrical position, the hips fold and extend without limitation, and the body feels free, unrestricted, balanced.
WHEN CAN INJURY OCCUR?
Iliopsoas injuries happen because of excessive force. This usually occurs in one of three ways:
1. Participating in highly energetic and repetitive activities
Iliopsoas strain results from excessive stretching of this muscle. During highly athletic activities such as agility or fetching a tennis ball, the dog’s body contorts at high speeds and the psoas works extra hard.
Iliopsoas sprains/injuries also occur when dogs do sharp turns or slip and fall trying to catch the ball.
2. Slipping and sliding with splayed legs
The psoas is prone to excessive stretching and tearing. When a dog slips or falls with his legs splayed out, the psoas can overstretch and injure.
Overstretched muscles become weaker leading to a weak core, instability in this area and torn muscles risk scar tissue.
3. Orthopaedic issues
Underlying orthopaedic conditions like hip dysplasia, back injuries and torn cruciate ligaments can cause a dog to protect the injury. They do this by tightening the groin muscle. This may lead to the psoas muscle to go into painful spasm.
WHICH DOGS ARE MORE PRONE TO ILIOPSOAS INJURY?
1. Dogs involved in highly energetic activities
Any dog that is involved in explosive and energetic actions – accelerating quickly, jumping, making tight turns, hard running. This is true for both sporting dogs and energetic pets. Examples include running the fence continuously and chasing after a ball.
Note the torque pressure placed on the spine in the movement of this dog.
2. Dogs with orthopaedic issues
Dogs suffering from hip dysplasia and cruciate injuries cause the dog to protect the joint by muscle guarding.
Muscle guarding leads to muscle strains. The muscle tries to protect a painful joint by limiting its range of motion resulting in pain and muscle shortening.
3. Weekend Warriors
These include dogs that are sporadically active. Dogs that are overtrained with limited recovery time, have poor conditioning and weak core muscles fall into this group. Dogs with poor conformation (such as abnormal spinal alignment) are prone to psoas related injuries.
4. Repetitive activity
Activities include repeated jumping with hyperextension of hind limbs. When a dog does a repetitive activity without variation it also does not allow other core muscle to build up.
Poor conditioning and weak core muscle can increase the risk of stretch injury.
5. Inadequate warm-up
Many times low impact warm-ups are skipped with athletic dogs and they are suddenly asked to jump or turn. An excited dog will do these movements with gusto and the sudden strain on cold muscles more easily lead to injuries.
The same is true for excitable pets at home or even having your dog jump out of a car to run and chase a ball.
6. Dogs with weak hindquarters, lower back pain.
Ongoing or repetitive minor injuries often go hand in hand with underlying pre-existing neurologic or orthopaedic conditions such as lower back pain, hip pain, or stifle disease. Similarly, dogs with core muscle weakness or weak hindquarters are at greater risk of slipping into a splay leg position and exacerbating a chronic injury.
~excerpts from Jackie Crawford of Canine Muscle Works, Australia
Cert. Animal Neuro-Myofascial Release
Cert. Veterinary Thermal Imaging
Cert. Canine Myofunctional Therapy
Cert. Emmett Therapy
Cert. Rocktape Canine Equine course
Dr Ingar Krebs ,DVM, Diplomate ACVS – Soft Tissue Faculty Surgeon, orthopaedic and neurologic surgery