4A – Sagittal STIR (4a) and axial fat-suppressed proton density-weighted (4b) images of the index finger in a 69-year-old male who presented with severe pain and swelling one week following a dog bite. Fluid distends the flexor tendon sheath on the sagittal image (arrowheads). The tenosynovitis is confirmed on the axial image (arrows), which demonstrates no intrinsic signal abnormality of the flexor tendons.