The palms-out wrist stretch includes muscles that span from your elbow all the way down to the base of your palm. That includes the flexor carpi radius and ulnaris, the palmaris longus, pronator teres and anconeus in the forarm. The flexor digitorum superficialis, flexor pollicis longus and flexor digitorum profundus of the palm are also involved.
Don't ever under estimate the importance of stretching and the benefits it holds.
The palms-out wrist stretch is good for tennis, golfer's or throwers elbow, as well as wrist sprain, dislocation or tendonitis. It also helps with carpel tunnel syndrome and ulnar tunnel syndrome.
Always rememberthat while stretching may be recommended to aid recovery out of injury, you should always be very careful when stretching through rehabilitation. Your soft tissues are likely to be more vulnerable to re-injury if you stretch too much or too hard during this time. Always check with your Health Care Professional who is guiding you through your recovery to make sure it is appropriate to start stretching, and please - ALWAYS FOLLOW THE RULES FOR SAFE STRETCHING (The first posting on this stretching blog).
Image taken from "Upper Body Stretches" wall chart by B. Walker.