Where Are Tendons in Thumb?

Two of the main tendons to the thumb pass through a tunnel (or series of pulleys) located on the thumb side of the wrist. Tendons are rope-like structures that attach muscle to bone. Tendons are covered by a slippery thin soft-tissue layer, called synovium.

Where do the tendons run in your thumb?

Thumb Tendons

The APL tendon runs on the radial side of the wrist (the side the thumb is on). Its muscle belly is in the forearm and then travels inside a tough band, or retinaculum, across the wrist.

What does tendonitis in the thumb feel like?

Pain near the base of your thumb. Swelling near the base of your thumb. Difficulty moving your thumb and wrist when you're doing something that involves grasping or pinching. A "sticking" or "stop-and-go" sensation in your thumb when moving it.