Carpal tunnel syndrome occurs when the tissues surrounding the tendons in your wrist swell or thicken, and put pressure on the median nerve. These tissues are called the synovium. The synovium lubricates the tendons and makes it easier to move your fingers.
This thickening of the synovium occupies more of the small space of the carpal tunnel, and over time, crowds the nerve.
In addition, tightness of the transverse carpal ligament can constrict the carpal tunnel space. This crowding can result in hand pain, numbness, tingling, and weakness.