This has proven to be a stumper for me! I teach an equine course at a local university and one of the activities I have the students do is a total recreation of the equine skeleton. Then, over the course of the year as we learn other anatomical features we add to the skeleton until we have the tendons, ligaments and some of the major muscles added. This worked great last year, we built a beautiful skeleton and had him hanging on the wall.
This year’s students are a bit more precise, however and while last year’s students didn’t think twice and set about cutting and pasting, the first question I had this year was “How long are each of these bones supposed to be?” I hadn’t given that much thought because it just “worked” last year! So I reply, “Well, lets do a quick search”…that was 2 weeks ago and I STILL haven’t come up with a good answer for them and they claim they CAN’T build a skeleton if they don’t know how long to make each of the bones. Valid point. I have even searched for a ratio of cannon:femur, or cannon:pastern … nada! So I appeal to you all, does ANYONE have a source that identifies anything about the length of various bones in the equine skeleton?
Seems as though the edit feature is not going to cooperate…the 
should actually be Cannon : Pastern
Here’s a pony club conformation reference that I recently found: http://midcalponyclub.org/images/files/Study-Guides/Study%20Guide%20Conformation%20Analysis.pdf
Lots of info on basic conformation, including faults, as well as “ideal” ratios and angles of bones.
Hope this helps!
the short pastern can be very short in some breeds such as a Lippitt Morgan… that is usually why most of the old style Lippitts are under 14.2h
The length ratio of bones is probably directly related to whatever job the horse is built to do. What works for an endurance horse isn’t the same as a calf roping horse or a draft horse or a jumper, etc.
Many years ago I wrote to “Riding” magazine when I lived in UK. The information below is not directly related to your question OP, but interesting nevertheless.
Phyllis Hinton, Editor, writes :
"…the following quotation from the late Lady Wentworth’s “The Authentic Arabian Horse” may give you the information you require.
"It has long been known that the Arabian breed differs so radically from all other breeds in formation of skeleton that it forms a separate species of the Genus Equus, representing the ‘hot’ side of equine genealogy which should be classified as Equus Caballus Arabicus. It is however, not generally known that having five lumbar vertebrae instead of the ‘normal’ six, it almost always has a rib less and two vertebrae less in the tail as well as the straight pelvis and the shaft of the ulna (small bone of the lower foreleg) complete which occurs in the zebra, but in no other breed of horse.
“The normal number of equine ribs and lumbar (ribless) vertebrae is as follows:
The ‘cold-bloodied’ common horse of heavier breed has 19 ribs and 6lumbars; the better bred horse l8 or 19 ribs, and the Thoroughbred almost always l8 ribs and 6 lumbars with an occasional greater or less number, as is to be expected from his combination of oriental speed with flaws of cold non-racing blood. The ordinary pony and horse stock has 18 ribs and 6 lumbars.”
It has been known for an Arab to have six lumbar vertebrae instead of five but it is not common. A few have had 18 instead of 17 ribs. This has no particular effect on cross-breeding.
Yours sincerely, Phyllis Hinton, Editor. (This was a hand typed letter with no erasing!)
