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Old Dog Back Legs Splayed Out and Shaking (Here’s Why)

By Patricia Williams
Last updated: August 21, 2026

Seeing an old dog’s back legs splayed out and shaking can be frightening, particularly when the change happens suddenly.

A dog that is struggling to keep its hind legs underneath its body may be experiencing weakness, pain, poor balance, or difficulty controlling its movements.

The suddenness and severity of the symptoms are important when deciding how quickly your dog needs veterinary care.

Table of Contents

Old Dog Back Legs Splayed Out and Shaking: Why It Happens

A dog may suddenly have its back legs splayed out and shaking when pain, weakness, muscle fatigue, poor traction, or a problem affecting the joints, nerves, or spine interferes with normal hind-leg stability.

Shaking can occur when muscles are working harder to support the body, but it may also accompany discomfort or neurological problems.

In an older dog, the combination of hind-leg instability and shaking deserves attention, especially if it is new, getting worse, or accompanied by difficulty standing or walking.

Old Dog Back Legs Splayed Out and Shaking: Symptoms

Depending on the underlying problem, other symptoms may occur at the same time, including:

Trembling or shaking in the back legs
Difficulty getting up
A wide-based or unsteady stance
Weakness after walking
Stiffness when moving
Dragging or scuffing of the hind paws
Reluctance to walk, climb stairs, or jump

Old Dog Back Legs Splayed Out and Shaking: Common Causes

Arthritis and Joint Pain

Arthritis can cause pain and stiffness in the hips, knees, and other joints. A painful dog may change its stance to reduce pressure on uncomfortable joints, causing the hind legs to spread farther apart.

Shaking may occur because your dog is uncomfortable or because the muscles are working differently to compensate for painful joints.

Stiffness after resting, reluctance to use stairs, and reduced interest in exercise are common accompanying signs.

Although arthritis is common in older dogs, a sudden worsening of mobility should not automatically be blamed on arthritis. A veterinarian can determine whether joint pain is contributing to the problem.

Slippery Flooring

Smooth floors can make it difficult for an older dog to maintain traction. If the hind legs slide outward, the muscles may tense and shake as your dog tries to regain balance.

This can be particularly noticeable when getting up from a lying position, turning, or walking across hardwood or tile.

Dogs with weak hindquarters, long nails, or painful joints may be especially vulnerable.

If the shaking and splaying occur mainly on slippery surfaces but your dog walks normally on carpet or another nonslip surface, poor traction may be contributing. However, a sudden change should still be monitored.

Hind-Leg Muscle Weakness

Older dogs can lose muscle strength because of aging, reduced activity, chronic illness, or orthopedic problems.

Weak hindquarters may make it difficult to stabilize the pelvis and keep the legs positioned underneath the body.

The muscles may shake because they are working harder to support your dog’s weight. You may also notice difficulty rising, reduced endurance, or a slower walking pace.

Gradual muscle weakness can often be addressed with veterinary guidance and appropriate activity. Sudden or pronounced weakness requires more careful evaluation.

Hip or Knee Problems

Pain or instability affecting the hips or knees can make it difficult for a dog to bear weight normally. Your dog may spread its back legs, shift its weight, or shake when standing.

Some orthopedic conditions cause intermittent problems, while others result in more persistent lameness.

Your dog may also have trouble getting up or may avoid movements that require the hind legs to work harder.

If one leg appears worse than the other, or your dog suddenly stops bearing weight on a limb, veterinary assessment is recommended.

Spinal Disease

Conditions affecting the lower spine can interfere with strength, coordination, and sensation in the hind legs.

An affected dog may have difficulty keeping its legs underneath its body and may appear shaky or unstable.

Other signs can include a hunched posture, reluctance to move, back pain, stumbling, or changes in paw placement. Some spinal problems can progress quickly.

Sudden hind-leg weakness, especially when accompanied by pain or difficulty walking, should be evaluated promptly.

Neurological Problems

The nervous system controls the muscles and coordination needed for standing and walking.

A neurological problem can therefore cause hind-leg shaking, weakness, or poor coordination even when there is no obvious injury to the legs.

You may notice paw dragging, knuckling, crossing of the hind legs, stumbling, or difficulty correcting the position of a paw. Some dogs develop a noticeably wide-based stance.

Neurological symptoms should be assessed by a veterinarian because treatment depends heavily on the underlying cause.

Pain, Anxiety, or Muscle Fatigue

Shaking is not always caused by a neurological problem. Dogs may tremble when they are painful, frightened, stressed, or physically exhausted.

An older dog that has difficulty standing may become anxious because it feels unstable. Similarly, muscles can tremble after exertion when they are fatigued.

If the shaking repeatedly occurs together with hind-leg splaying, however, it is important to look for an underlying physical cause rather than assuming the dog is simply tired or anxious.

More Serious Neurological or Systemic Disease

Severe weakness affecting the hind legs can sometimes occur with serious neurological or systemic disease.

Depending on the condition, a dog may develop marked difficulty standing, loss of coordination, profound weakness, or other changes.

A dog that suddenly cannot support its hindquarters should be treated as needing urgent veterinary assessment.

Waiting to see whether severe weakness resolves on its own can delay diagnosis of a potentially serious problem.

Old Dog Back Legs Splayed Out and Shaking: What to Do

If your senior dog’s back legs are suddenly splaying outward and shaking, veterinary assessment should come first to determine whether pain, weakness, a neurological problem, or another underlying condition is responsible.

Once your veterinarian has addressed the cause, supportive mobility products can help make everyday movement safer and more comfortable.

Paw grips may improve traction on slippery floors, while a rear support harness can provide additional stability when standing or walking.

An orthopedic bed can also provide supportive cushioning during periods of rest. Learn more in our guides to the Best Paw Grips for Senior Dogs, Best Dog Harnesses for Weak Back Legs, and Best Orthopedic Beds for Senior Dogs.

You can also explore our Senior Dog Products hub for more mobility and comfort recommendations for aging dogs.

When to Call or Visit the Vet

Because both shaking and hind-leg instability can have several causes, a new or recurring problem in an older dog deserves veterinary attention.

Schedule an appointment if you notice:

Repeated hind-leg shaking
Recurring episodes of the legs splaying outward
Increasing difficulty getting up
Stiffness or persistent weakness
Changes in walking or balance
Paw dragging or scuffing
Reluctance to exercise
Signs of joint, muscle, or back discomfort

Seek emergency veterinary attention immediately if your dog develops:

Inability to stand or walk
Sudden severe hind-leg weakness
Paralysis or inability to move a limb
Severe or rapidly worsening pain
Significant loss of coordination
Sudden loss of bladder or bowel control with hind-leg weakness

Collapse or extreme distress

Old Dog Back Legs Splayed Out and Shaking: Treatment

Veterinary treatment for an old dog whose back legs are splayed out and shaking starts with a thorough examination of the paws, joints, muscles, spine, and nervous system to determine whether pain, weakness, an orthopedic problem, or a neurological condition is responsible.

The veterinarian may recommend X-rays or other diagnostic imaging to identify problems that are not visible externally, while blood tests may be performed when appropriate.

Treatment may include prescription pain relief, anti-inflammatory medication, restricted activity, physical rehabilitation, mobility support, or other targeted therapy based on the diagnosis.

Recovery and Monitoring

Recovery depends on the underlying cause. A dog whose legs are slipping because of poor traction may improve after environmental changes, while arthritis, joint disease, spinal conditions, or neurological problems may require ongoing veterinary management.

Monitor your dog’s ability to stand, walk, turn, and lie down.

Pay attention to whether the shaking becomes more frequent, lasts longer, or begins occurring while your dog is resting.

Keep your dog’s environment as safe as possible by reducing slippery surfaces and limiting activities that require jumping or sudden movements.

Follow your veterinarian’s instructions regarding exercise and rehabilitation.

If your dog has a chronic mobility condition, long-term management may include appropriate exercise, rehabilitation, environmental modifications, and veterinary-directed treatment. Regular follow-up can help determine whether the condition is stable or changing.

Key Takeaway

An old dog with back legs splayed out and shaking may be experiencing poor traction, muscle weakness, arthritis, joint pain, spinal disease, or a neurological problem.

Shaking can occur when muscles are struggling to support the body, but it can also be associated with pain or impaired nerve function.

A brief episode caused by slippery flooring may be less concerning than sudden weakness that persists or keeps returning.

Because older dogs can develop orthopedic and neurological problems, new hind-leg instability should not automatically be considered a normal part of aging.

If your dog cannot stand, develops severe weakness or pain, or suddenly loses normal movement or coordination, seek emergency veterinary attention. If the symptoms persist or recur, a veterinary examination can help identify the cause and provide an appropriate treatment plan.