A cat with a sore back does not limp and does not cry. It stops jumping onto the 60 cm windowsill, sleeps on the floor instead of the bed, and grows a patch of matted fur where it can no longer reach to groom. By the time a limp appears, the problem has usually been running for 3 to 6 weeks. The 0 to 4 scale below is the fastest way to decide whether this is a Monday appointment or a 2 am drive.
Grade 0 to 4: locate, then decide how fast
Grade the cat on its worst moment in the last 24 hours, not on how it looks in the clinic, where adrenaline hides a lot. Grade 0 is a normal gait and a normal jump. Grade 1 is a stiff walk on rising, a jump height down by about a third, and no reaction to firm pressure beside the spine. Grade 2 is a visibly shortened stride, refusing the 60 cm shelf, and a flinch or a hiss when you press the long muscles 2 cm either side of the spine. Grade 3 is ataxia in the hind legs, knuckling of the paws, and no jumping at all. Grade 4 is dragging, paralysis, or a cat that cannot urinate, and that is an emergency within hours, not days.
| Grade | Walk | Jump height | Reaction to back touch | See a vet within |
|---|---|---|---|---|
| 0 | normal, 4 paws even | normal, 100 percent | none | routine visit |
| 1 | stiff for the first 3 to 5 steps | down about 33 percent | none, muscles tight | 3 days |
| 2 | short stride, head low | refuses 60 cm, uses 30 cm | flinch or hiss | 48 hours |
| 3 | ataxia, paws knuckle over | 0 cm, no jump | cries out, guards | 24 hours |
| 4 | drags hind legs or cannot stand | 0 cm, no jump | may feel nothing at all | 0 hours, same hour |
Three groups of causes
The first group is degenerative: intervertebral disc disease, and the spinal osteoarthritis that shows on X-rays in most cats past 12 years. Disc extrusion is rarer in cats than in dogs, but when it happens it is usually thoracolumbar and it progresses over 24 to 72 hours. The second group is traumatic: a fall from a 3rd floor window, a door shutting on the tail base, a dog bite, or a hairline fracture of a lumbar vertebra that a cat hides for a week. The third group is everything that mimics a disc: discospondylitis from a bacterial infection, spinal lymphoma, a vertebral tumor, and referred pain from pancreatitis or kidney disease, which is why a back that hurts on palpation still needs blood work.
Three minutes of observation at home
Watch the cat walk away from you on a hard floor for 10 steps, then walk toward you for 10 more: a cat with back pain drops the head, shortens the hind stride, and swings the pelvis rather than flexing it. Then put a hand flat on the spine and press gently with 2 fingers, 2 cm to each side, from the shoulders to the tail base, and note where the skin ripples or the cat turns. Then lift the food bowl 15 cm and see whether the cat stretches up or sits down to eat. Three signals, 3 minutes, and a grade you can take to the clinic.
Never lift the hind legs
Lifting a cat by the hind legs, or pulling the tail up to look underneath, extends the spine at exactly the segment where a disc is most likely to be extruding. In a cat with a fractured vertebra it can displace the fragment and turn a grade 2 into a grade 4 in one motion. The safe lift is one hand under the chest and one under the pelvis, keeping the spine level, and a cat that cannot stand should be moved on a rigid board, not carried like a handbag.
Never massage the spine
Deep pressure along the spine does two bad things. It increases disc pressure at the affected segment, and in a cat with spinal instability it moves tissue that should be still. The muscles beside the spine are usually in spasm for a reason: they are splinting a segment that hurts, and releasing them removes the splint. Warm compresses for 10 minutes at 38 to 40 C on the long muscles, not on the spine itself, are the version that does not carry that risk.
The two checks that actually decide the plan
Check one is the neurological exam, done by hand and taking 5 minutes: proprioceptive placing (turn a paw over and see if the cat rights it), the withdrawal reflex in each hind limb, tail tone, and anal tone. A cat that drags a paw but rights it is a different case from one that does not right it, and the difference decides whether the cat goes home or goes to imaging. Check two is imaging: plain X-rays in 2 views, lateral and ventrodorsal, under sedation, which show bone, alignment, and disc space but cannot show the disc itself. If the neurological exam is abnormal, the next step is MRI or CT, and those are the only ways to see a extruded disc or a spinal tumor.
What the timeline looks like
A cat at grade 1 with no neurological deficit is usually managed with 4 to 6 weeks of restricted jumping, a ramp to the bed, and a recheck at 2 weeks. A grade 2 cat gets the same plus pain control and a stricter 48-hour observation window; if it worsens by one grade in that window, imaging moves up. A grade 3 cat needs imaging within 24 hours, and a grade 4 cat needs a referral centre the same day, because the window for decompression is measured in hours and a cat that loses deep pain for more than 48 hours has a much lower chance of walking again.
Five things to do tonight
- Grade the cat twice: once now and once after 24 hours, and write both numbers down.
- Put a 30 cm step or a ramp in front of the 2 highest places the cat uses, and block the rest.
- Move food, water, and litter to one room at floor level so the cat stops climbing for 48 hours.
- Check the litter box for urine output: no urine in 12 hours with a grade 3 or 4 cat means go now.
- Book the neurological exam, not just an X-ray, because a normal X-ray with a grade 2 cat proves very little.
Related: how cats hide pain in general in hidden pain signs, why a suddenly aggressive cat is often a hurting cat in sudden aggression and pain.
Frequently asked
How do I tell if my cat's back hurts?
Look at function, not at crying. A cat that stops using the 60 cm shelf, walks with a shortened hind stride and a low head, and flinches when you press 2 cm beside the spine is showing back pain. Grade it 0 to 4 on its worst moment in the last 24 hours.
Why should I not lift a cat by the hind legs or massage its spine?
Both extend or load the segment where a disc is most likely to be extruding. Lifting the hind legs can displace a fracture fragment and turn a grade 2 cat into a grade 4 in one motion, and deep massage removes the muscle splint that is protecting the sore segment.
Do X-rays show a slipped disc in a cat?
No. Plain films in 2 views show bone, alignment, and disc space narrowing, but not the disc itself. If the neurological exam shows a deficit, MRI or CT is the next step, and that is the only way to see an extruded disc or a spinal tumor.