Pastern swollen on one side? Any ideas?

[kit279]

My TB has had a slight swelling on the outside of his hind right pastern for a day or two and I'm wondering what it is. He's not lame at all but is a little tender when it's handled. The fetlock and rest of the leg is not puffy at all and there's no heat. I'm just wondering if anyone has seen anything like it before?

The swelling is about the size of an egg and not huge, quite soft. I wondered if it was a bruise/haematoma under the skin as he has been full of the joys of spring recently and therefore hooleying about! I'm paranoid about a tendon injury as the ground is like concrete at the moment..

Any ideas?

 

[arwenplusone]

Could it be a windgall?

 

[kit279]

I don't think so because the fetlock itself isn't swollen at all and the swelling is quite soft. It's definitely on the bony bit of the pastern...