Figure 12. (a) Septic tenosynovitis. Sagittal short tau inversion recovery (STIR) image demonstrating a rim of high signal (arrows) enveloping the extensor hallucis longus (EHL) tendon indicating septic tenosynovitis. The tendon itself returns normal low signal. Note the presence of septic arthritis of the first metatarso-phalangeal joint. (b) Coronal T2 fat-saturated image demonstrating septic tenosynovitis of the EHL tendon.