Carpal tunnel is a small space that's in the center of the wrist. Carpal tunnel is the swelling of tendons in a very tight space. When the swelling gets to a certain point, the nerve gets compressed and squeezed, and all these symptoms occur.
So many things can cause that nerve to be compressed. Primarily it’s swelling in the tendons that go into the hand. Many different things can cause it, including pregnancy, overuse activities, excessive use of the hand, strenuous activities.
Some diseases can also cause or predispose you to swelling in the flexor tendons, including diabetes and thyroid issues. But it is primarily repetitive use and overuse of the wrists that causes swelling in those flexor tendons. That could be too much tennis, too much time on the computer, too much gardening, sometimes also too much cooking, cleaning around the house.
Many times patients are predisposed to swelling and then they do those activities and then it presents as excessive swelling in those flexors tendons.