More often than not, it emanates from a repeated motion or forceful use within your finger or thumb. Tendons are fibrous cords that attach muscle mass to bone. Each tendon is surrounded by a protective sheath.  Tendon mend: The surgeon tends to make an incision inside the pores and skin https://www.theorthopaedicandpainpractice.com/why-cant-i-straighten-the-tip-of-my-finger/