Final answer:
The pain associated with wrist and finger extension over specific tendons suggests tennis elbow, or lateral epicondylitis, a condition common in repetitive movements of forearm muscles. Golfer's elbow, DeQuervain's disease, and intersection syndrome affect different tendons and areas, so they are less likely the issue in this case.
Step-by-step explanation:
When wrist and finger extension causes pain specifically over the extensor carpi radialis longus tendon and the extensor digitorum communis, the condition one would suspect is tennis elbow. Also known as lateral epicondylitis, tennis elbow is an injury that involves the tendons attached to the outer (lateral) part of the elbow which are used during the extension of the wrist and fingers. This condition is frequently associated with activities that involve repetitive use of the forearm muscles, such as playing tennis. The pain in tennis elbow is typically on the outside (lateral side) of the elbow and may extend down the forearm. Treatment for tennis elbow includes rest, ice, nonsteroidal anti-inflammatory drugs (NSAIDs), physical therapy, and, in severe cases, surgery might be considered if non-invasive methods are ineffective.
Golfer's elbow, or medial epicondylitis, affects the tendons on the inside of the elbow and is less likely to be the cause when the pain is located over the extensor tendons. DeQuervain's disease and intersection syndrome affect different areas of the wrist and the tendons involved in thumb movement, hence making tennis elbow the most likely diagnosis in this scenario.