About 10 ~blood~ vessels and ~nerves~ and more than 20 ~tendons~ pass through the wrist area. These are bound by two fibrous muscle bands that cuff the entire wrist and lie just under the skin. The two bands, the |flexor retinaculum| and the |extensor retinaculum| work together. The |flexor retinaculum| is a deep, thick fibrous band that lies on the palm side of the wrist and creates the carpal tunnel for the passage of the long flexor ~tendons~ of the fingers. The |extensor retinaculum| attaches to the |ulna| (the forearm bone on the index finger side) and crosses the back of the wrist and attaches to the ridges on the distal end of the |radius|.
