To better understand finger tenosynovitis, it helps to understand the anatomy of the finger.

Each finger contains three bones, while the thumb contains two bones. At each joint, the bones are held together by ligaments. Muscles in the hand or forearm turn into tendons, which also attach to the bones in the finger: the muscles move the fingers by pulling on the tendons.

Anatomy examples:

• Hand bones
• X-ray of the hand
• Bones and tendons of the finger
• Fingertip
• Finger fracture

Tendons are strong, fibrous bands or cables that attach muscles to bone. The muscles pull on the tendons to make the fingers bend or straighten.