Most of the time, it arises from a recurring movement or forceful use of one's finger or thumb. Tendons are fibrous cords that connect muscle to bone. Each and every tendon is surrounded by a protective sheath.  Weak point in Grip or Pinch Patients could encounter issues in gripping objects https://www.theorthopaedicandpainpractice.com/why-cant-i-straighten-the-tip-of-my-finger/