What this means
A dog's back is normally nearly level or gently curved. When it rises upwards the dog looks hunched: belly tucked in, legs gathered under the body, steps short and sometimes careful. That is how a dog with back or belly pain often looks, but muscle stiffness or spasm can produce the same posture.
In some dogs the back arches only briefly, for example during play or excitement, and after a while everything returns to normal. This may be an inherited muscle or movement problem, but a vet makes that call, not the owner. Sometimes a hunch hides a back injury or a disc problem.
Do not massage the back or try to straighten it. Notice when the back arches, whether it is a constant posture or short episodes, and whether your dog also whimpers or avoids stairs and jumping. If you can, film your dog walking and hunching. A video is easier for a vet to judge than a description in words.
Possible causes
These are things that can cause this sign. It is not a diagnosis, and they are not equally likely for your dog.
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A back injury or strain
After a fall, a jump or a harsh movement the back may hurt. The dog walks carefully, hunches and avoids climbing.
About the condition: Back injuries -
A problem with the discs between the vertebrae
When a disc presses on the spinal cord or nerves, the back becomes painful. The neck may stiffen or the hind legs weaken at the same time.
About the condition: Intervertebral disc disease -
An inherited muscle stiffness problem
In some dogs the back briefly arches and the legs stiffen during play or excitement. After rest everything returns to normal.
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Episodes of muscle cramping
Short muscle spasms can arch the back and stiffen the legs. The episodes pass but may recur.
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Belly pain
A dog with a sore belly may tuck it in and hunch. Vomiting or dullness is then often seen as well.
What else to watch for
These observations help your vet build the picture faster. Note down what you saw and when.
- Whether the back is arched all the time or only in short episodes
- When it happens: during play, excitement, after rest or for no reason
- Whether the legs stiffen at the same time or the walk looks unnatural
- Whether your dog avoids stairs, jumping or getting onto the sofa
- Whether it whimpers, growls or pulls away when the back is touched
- Whether everything returns to normal after rest
When to book a routine visit
If your dog hunches, walks hunched or its back arches during play, book an examination and show a video of the behaviour.
Related conditions
Conditions whose entries mention this sign. The list is somewhere to read on, not a way to reach a diagnosis.
- Back injuries Bones and joints A dog's back can be hurt by an accident or by changes in the spine itself, such as damaged intervertebral discs pressing on the spinal cord. This causes pain and sometimes weakness or even paralysis, so it is not something to wait out. Only a vet can judge what is going on and how urgently help is needed.
- Canine epileptoid cramping syndrome (Spike's disease) Nerves and muscles This is a condition in which a dog has episodes of muscle cramping: the muscles tighten involuntarily and walking becomes uncoordinated. Unlike in an epileptic seizure, the dog stays conscious throughout the episode. Because other illnesses can look similar, a vet decides whether this is the cause.
- Intervertebral disc disease Bones and joints Intervertebral disc disease is a condition in which the discs that cushion the spine between the vertebrae degenerate, bulge or rupture and start pressing on the spinal cord or nerves. This causes pain and, in more serious cases, weakness or even paralysis of the legs. The damage can happen suddenly, even after a perfectly ordinary jump, or build up gradually, so it is not something to wait out.
- Scottie cramp Nerves and muscles This is an inherited disorder of the nervous system in which excitement or physical exertion brings on episodes of muscle stiffness and cramping. The dog stays aware throughout the episode and moves normally again after a short rest. Other disorders can look similar, so a vet decides what is really going on.
Body systems: Bones and joints Nerves and muscles