Flexor tenosynovitis is a bad infection in the finger. It usually requires surgical intervention for treatment. The current standard of diagnosis is primarily clinical, sometimes with the help of blood tests. Since the disease process should produce a fluid collection around the flexor tendon sheath - the idea in this study is that perhaps ultrasound can visualize that fluid and clench the diagnosis. This would lead to ensuring the proper treatment to those who need it and potentially avoiding an unnecessary operation for those who don't. So how well does this plan work out? Should we be doing this routinely?