Muscle knots in the Adductor Pollicis are located deep in the palm of the hand, especially between the thumb and the base of the index finger. These muscle knots can refer pain to the base of the thumb, the webbing between the thumb and index finger, the thumb, the center of the palm, and even into the wrist, often mimicking carpal tunnel syndrome or arthritis. You may feel aching, weakness, or cramping during pinch grips, writing, texting, or any activity requiring fine thumb control.