health issues with my very old iguana

Question
My iguana is about 15 years old if I've done my math correctly. She has always been very healthy until recently.
She seems to be getting very bony. I don't really know how to describe it any better, except she seems to be losing muscle{?} so that her bones seem to protrude. Just this evening her tail got hooked on one of her branches and it did not break off but it seems broken and separated but still within the skin. I feel so horrible that this is happening to her and i have no idea what's causing it. She still continues to eat and go about her business. Do you have any ideas what could be the problem???
I am very distressed- please help!
Thank you, Holly

Answer
Hi  Holly and Robert.
I commend you on getting your ig to 15 yrs of age so far!!
It sounds like she may be having some calcium issues or nutritional problems that she is not using the nutrients in the foods she is eating....and other age related problems with iguanas.  Although 15 isn't old for an iguana..many never make it to even that age due to genetics. She may have some kidney issues going on, and of course there can be other reasons..BUT..the fact she is eating, etc is a good sign.
I am including some info on UVB, which has changed in the past year or so. I also do recommend a vet check up for some bloodwork which can tell what may be causing her problems.
LIGHTING:
Supplying uvb can be done in a few ways. By special lights
that come in fluorescent tubes or special screw in bulbs
(mercury vapor)that are designed to produce uvb and heat.
The tubes do not produce heat. UVB is needed by the reptile to be able to absorb the calcium in the foods they eat.
With out the uvb, they will develop metabolic bone disease.
With the tubes, they must say that they produce BOTH uvb and
uva. The uvb needs to be 5% or higher. Repti Sun 10.0 and the Repti Glo 8.0's are a great source for uvb. The old "favorites" are the repti sun 5.0 or the Iguana light..which are the same tube, just different package.
There are tubes that say ''full spectrum'' but they do not produce any uvb.
These need to be positioned 6-8 inches over the reptile for the 5% and 8% and 8-10 inches for the 10% so
that they get the uvb that is needed. The tubes need to be replaced every 6-9 months as that they stop producing UVB long before they stop producing light.Using a fixture that holds two uvb tubes of at least 3 feet in length will provide adequate uvb for your iguana. There has been new studies that have proven that compact uvb lights, both the spiral/coil type and the ones that look like long "U's" laying on their side and a few other brands are causing what basically amounts to snow blindness in reptiles.  To read more on this, you can go to http://www.uvguide.co.uk/index.htm
On the mercury vapor , they also produce heat. They also
produce the uvb and uva. The best on the market now are the
Mega Rays.(http://www.reptileuv.com) The distance from these are greater than the uvb tubes and the directions must be followed that
are listed for the light. When using the mercury vapor
lights, you don't need to have one light for uvb and one for
heat. The Mercury vapor lights provide both.
For daytime heat, if using the tube uvb, regular household
incandescent light bulbs produce heat. The wattage will
depend on the size of your iguanas enclosure. and the room temperature.Of course, the best uvb is from the
sun and if you are in an area that you are able to take your reptile outside in a proper enclosure, (Never a tank or enclosed, solid cage)

To find a qualified vet in your area you can go to
http://www.herpvetconnection.com
http://www.arav.org/ECOMARAV/timssnet/amm/tnt_mdsearch.cfm
http://www.anapsid.org/vets/