A client came to me suffering from pain in his big toe. The pain was actually on the bone at the base of his toe, which is the first metatarsal, the long bone along the inside of his arch.
Normally this problem is caused by tension in the muscle that runs along the outside of your shin bone, the muscle called tibialis anterior. The tibialis anterior crosses over the front of your ankle and inserts onto the bone along your arch. When the muscle pulls on this bone, it pulls the back part of the bone, the portion that is closest to the inside of your heel, and draws it toward the inside of your foot. That will then push the forward part of the bone, the part that is just before you big toe, out and away from your toe — and cause a bunion. The treatment involves treating the spasms in your tibialis anterior and applying pressure along the bone.
However, for my client, his problem came from cycling shoes that put too much pressure on the front of his foot. I worked on all of the muscles of his foot, and then showed him how to continue the treatment at home, and it helped. He also realized that he needed to check on his shoes and get a new, better fitting, pair.
I guess not everything is caused by a muscle!