The fourth cause of a bunion is due to subluxation. Subluxation is just a fancy word, that means the bones aren’t in the right spot, the easiest way to imagine it is like a loose bag of bones.
Now when they are loose or not well supported, the foot tends to fall in wards due to centre of gravity.
Okay, when this happens, this causes internal rotation through the foot, ankle and the leg… A bit like this.
When your foot is in this position, you tend to push off through the inside of your big toe as opposed to the centre of it over time as you push off the inside of the big toe, this can make the big toe deviate inwards because it is constantly being forced in that direction.
If you do get calluses on the inside of your big toe, then this is most likely happening to you.