There are joints, ligaments, tendons, tendon sheaths and other structures at the base of the thumb, so the first thing to consider is whether there has been an excessive external force injury causing the local pain. For example, accidental falls or heavy lifting can cause local soft tissue injury, and trauma is also the most common cause. Secondly, we need to consider whether there is tendinitis. Generally, people who work with their hands for years or have special hand movements will have pain at the base of the thumb, and the pain is more severe when the finger is bent or straightened. Sometimes there may be symptoms of immobility of the thumb, or inability to straighten it after bending or bend it after straightening. Arthritis can also be a cause of pain. Arthritis can cause pain along with swelling of the joint, and there may be redness and heat. If you have local pain, it is best to go to a regular hospital first and seek treatment after the diagnosis is confirmed.