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Lizard Rear Limb Problems

The facts about why your lizard can't move its back legs.

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Question 1:
I just picked my monitor up from the pet store a few days ago. At the time he ran around on all fours. Ever since I got him home, he seems have lost the use of his rear legs and continues to pull himself along with his front legs. He has been eating, but obviously I am very concerned with his condition.

Question 2:
I have a question regarding my iguana. About three weeks ago I noticed that my iguana can’t use his back legs. He can move them slightly, but he cannot use them. Now, starting this week, the same thing is starting with his front left leg. He isn’t really eating. He cannot move his tail at all. What is going on here? I do not understand? Is he dying?

Question 3:
We have a water dragon that is about a year old. A few days ago I noticed his hind legs were dragging. It looks as though he might be constipated because I haven’t noticed any signs of him going to the bathroom. We feed him lettuce, meal worms and crickets. Any hints?

I have grouped these three questions together because they all address lizards with the inability to use their hind legs. These problems have occurred in three different species of lizard, showing that this particular problem can happen to just about any type of herp.


In answering these questions, I am a bit frustrated that none of the owners gave me information regarding full-spectrum lighting for their pets’ habitats, and only one mentioned diet but even that information was quite sketchy.

Readers, when writing in to ask me a question, please include the herp species, minimum and maximum temperatures in the habitat, mean humidity, lighting (basking and ultraviolet, and how often replaced), what food you offer (in detail, including if insects are gut-loaded), what commercial food items are offered, what specific types of vegetables and fruits are offered and any supplements provided. Also, let me know if your herp is housed alone or is with other animals, and if so, what type and how many. This information is really helpful to me when assessing your herp’s problems.

With all three of these lizards, I suspect nutritional secondary hyperparathyroidism (NSHP), a form of metabolic bone disease (MBD). I have discussed this syndrome previously in several of my online columns, so please take a few minutes to check through the archived questions and answers to read up on how and why this happens.

The short explanation is this: a herp that does not receive enough calcium in the diet, or one that does not have full-spectrum lighting (especially the UVB portion), or the full-spectrum light is not changed as directed by the manufacturer (ultraviolet emissions are usually the first to peter out, so the light will still appear good), or the herp does not receive natural sunlight (not filtered through glass or plastic), then the herp will begin pulling calcium out of the bones in order to maintain the correct calcium level in the bloodstream, which is vital for normal functioning of all organ systems. As the bones become decalcified, the bone structure weakens, so over time the bones of the spinal column may collapse inward, often resulting in nerve damage of the back legs. Leg bones may develop spontaneous fractures, which are called folding fractures. Many deformities of the bones are possible.

One of the first signs of NSHP may be that the lizard no longer walks by lifting up its body and begins dragging itself close to the ground. The hind legs and tail often are the first to show signs of weakness, and then flaccid paralysis may occur. If the spinal cord is damaged from the spinal vertebrae (bones) collapsing, then other signs may develop, including constipation. In some cases, the herp may begin twitching or may even develop seizures related to the low blood calcium levels.


In all three of these cases, hind end weakness/paralysis is a sign of possible NSHP and warrants a trip to your herp vet for physical examination, lab testing, radiographs and appropriate treatment after diagnosis. Although deformity to the bones may be permanent, it is possible to stop the bony changes and even to strengthen the bones through the use of a hormone called calcitonin salmon.  But it is important that each of the lizards receive veterinary medical care as soon as possible.

There are other diseases and problems that can result in hind leg lameness or constipation, so this is another reason why any lizard with those signs should be evaluated by a qualified herp vet in order to have the problem correctly diagnosed and treated.