Bump on spine after riding

Boarder has a TB gelding. Recently, after she rides, there is a small bump on his spine about a hands widths behind the withers. The saddle or pad does not appear to put pressure on that spot. The bump goes away within a couple hours, and is not sore to the touch.

Any ideas on the cause/fix?

This could be a “hands-on” thing, where you need to be touching the horse.

Start with checking the tack, saddle for a stitch knot, uneven padding, thin padding in that area. What kind of pad? I hate thin ones, horse feels everything. Pad might also have a worn spot, thin place in the depth of his cushioning, allowing horse to get 'bruised" when ridden.

Have boarder tack up as usual, then get on horse. You try running your hands under the saddle where she is sitting, then under the pad on horse skin. Can you FEEL any extra pressure on the spot that gets the bump? Sometimes weight in the saddle changes how things fit on horse. Then watch her ride, she may be riding unevenly or coming down harder at certain times, so is impacting that spot harder than the rest of his body.

If you can’t find anything, having a saddle fitter check things could find issues you missed with less skilled training.

We had a saddle “go bad” on us after using it for quite a while on one horse. Horse was NOT happy, when he always had been before. Took horse and saddle to the Saddle Fitter, who told us after checking saddle that the tree was warped! One part was just digging into horse, so he was TELLING us he had a problem.
Thinking back, saddle got used and soaked during an incredibly heavy rain storm. It was High School Equestrian Team District Meet, could not avoid riding. There was over 12 inches of rain, with kids competing in it!!

I had let the saddle air-dry over a week, never thought about possible tree warping that the Saddle Fitter found. Had to get the kid a new saddle, since she needed to ride daily and couldn’t get the other saddle a new tree in time to keep things rolling along.

So always surprises to be found with saddles! Try helping her with the hand testing under rider. If nothing is found, time to get a Saddle Fitter involved. Her tack might just be wrong for the horse or there may be hidden issues. Either way, horse getting bruised and sored each ride, is going to make him CRABBY. He will quit cooperating since it ALWAYS hurts to be ridden. Things could get ugly.

My horse, as a 4 year old, used to get a similar bump. The saddle fitter explained that it was because of his lack of fitness. She recommended riding him in a frame. As he muscled up, he stopped getting the bump. Get a good saddle fitter out to check the saddle, just to be sure.

She rides in a Wintec CC, with a thickish AP pad, and an Oglivy half pad.

The bump on the spine is small. Like a dime size. Doesn’t seem to care if we press on it. She is carful to pull her pads up into the gullet, so as far as I can tell there really isn’t anything touching this place. Could pressure lower down cause a bump higher up?

I have seen that as well, exactly as you describe it.

For sensitive skinned horses, that can be from heat, or maybe a tad of friction.

I keep an eye on it. So long as it goes down soon, as you say and the area isn’t sore when I palpate it (while the bump is gone), I don’t worry about it.

And in general, my solution to keeping on top of saddle fit really is to palpate my horse’s back often. I know what the muscles feel like all the time-- after some time off, after hard work right away, that night, the next morning. In general, the muscles should feel rubbery and alive. Thin and taut is the first sign of trouble. And this method, plus some management things like letting the horse roll after work and often, prevent lots of problems.

I can think of only two occasions on which I’ve had to have a massage therapist bail me out of a fitting problem. The people who have a massage person or, worse, a chiropractor tell them to do 6 months of rehab from a saddle fitting disaster probably spend 6 months digging that hole for themselves.

My point, OP, is that you can get a lot done by doing as you are-- keeping daily tabs on it and asking if, in fact, the bump turns into anything bigger/functionally significant or not.