Radiographs are generally taken of the navicular bones, proximal sesamoid bones, fetlock joints, tarsal joints, and stifles. Their are different views generally requested by American Veterinarians and should be clarified with you and even a list and/or small illustration is handy to have to be able to communicate exactly what your Vet may wish to see. The radiographs are reviewed and examined for bone chips, bone remodeling, and OCD. The radiographs are often graded into 1 of 4 classes by the European veterinarians given an evaluation for risk of potential future lameness. American Veterinarians tend to give an opinion but not a ranking.
1.Good/satisfactory: Acceptable
2.Satisfactory: Acceptable, although bone changes indicate increased risk; "We see more bone changes, but they are changes that are acceptable for competing. The horse has a 30 percent prognosis for lameness."
3.Moderate: Usually acceptable; Changes judged in accordance with the clinical examination findings. Seen on older horses with more training and competitive experience.
4.Unsatisfactory: Not acceptable for use
Sample view of typical xray

In addition to the radiograph portion of the Pre-Purchase examination a clinical evaluation of the horse on a lunge line on hard ground, on soft ground and if possible under saddle assists the veterinarian to make a fair assessment of the soundness of the horse. There is a well known saying among many experienced horsemen and veterinarians - "horses dont read xrays". This is because many horses can xray completely clean and sound and yet is lame and the reverse can also be true. This is where a trained experienced rider can really assist in determining the real soundness of the animal because often they will feel something long before it becomes evident either in the xrays or the clinical. The xrays can also tell you sometimes when there is thickening of the bone structure that there may be an old injury possibly even to a suspensory. An experienced Veterinarian with the breed of horse you are purchasing is essential to knowing what the report and pictures really mean.
It has been our experience that our on-site veterinarian who is doing the exam usually prefers that the purchaser or their agent is present as this assists in their being able to discuss various aspects of the visual and clinical exam that is sometimes more meaningful visually. Mouth, and teeth are examined for condition and position - this is extremely important in purchasing a horse for future use as an upper level horse with the type of bits that are used for instance. Eyes are scoped to determine health and visual soundness. The horse should be examined and palpated along the vertebral column, each limb and along all joints and tendons, each hoof with hoof testers, and the hoof percussion with the shoes and the symetry of the hoof and the overall conformation of the horse should be looked at. The heart rate and respiration need to be checked at rest and after each gait on the lunge. Obviously the famous flexion tests of the distal limb including stifle and patella.
Sometimes an ultrasound may be used to look at soft tissue - again it depends on the use of the horse and the age and other factors as to whether someone should decide to pursue this additional look.
We recommend that after the xrays and pre-purchase are done in Europe that they be sent digitally to your veterinarian for review and/or discussion. Optimally it would be nice if the Vet Check can be done at a time that both veterinarys may speak during the exam. And if your forward your vet check and copies of the papers we can help insure the horse for transport and full mortality and major medical.
Notes on Selling
All of the above is excellent advice when buying - however it should be noted if you are selling - it is really a cost effective way to ensure that you may receive the necessary sale price if you have done all or most of this ahead of time so that you understand what you are dealing with and there are no ugly surprises when you think you have the horse sold and then find out "he didnt vet".
More Tips on Selling
When selling a horse the hardest and most important part is to be realistic about the market and your horse. It does not matter to the buyers how much you spent on buying, boarding and training; thats just the cost of owning a horse. Do a search to find out what horses are going for that are similar in training, experience, breed and all the other things that buyers look for when buying a horse.
Be professional in marketing - for goodness sakes dont use that awful picture in the pasture where the horse is not turned out to their best advantage and even though you may think that picture with your little kid on the horse is cute - if thats not what you are selling dont use it. Be very honest and up front - no one likes to waste time on a horse that does not meet their criteria. Be accommodating to buyers sometimes they are harder to find than you may think.
Avoid the buyers who try to bully or beat you down on price. If you are priced right you dont have to put up with this behavior. Also avoid the bully trainers who think they know it all and dont. Find a reputable trainer check their references and look at the scores on USDF - you would be amazed at the difference between what many of these so called trainers (USDF is working on this by educating and designating levels of education) claim and the reality.
Lastly if you dont have the time, or ability to create or pay for high quality pictures and videos you will save alot of headache and money by dealing with professionals who will show the horse at his best and can handle the vet checks. Expect to pay between 10 and 20percent for these professional services - But you may be pleasantly surprised that they made you money and saved you heartache.