The most common tendinitis affecting the deep digital flexor tendon (DDFT) occurs in the forefeet of sports horses. Ultrasonographical examination is an effective diagnostic tool complementary to radiography. Ultrasonographical examination of the foot consists of the suprasesamoidal area (proximal aspect) using a microconvex probe (5 to 7.5 MHz) and, also the sesamoidal and infrasesamoidal areas (transversal aspect) with a convex probe (5 to 7.5 MHz). In cases where a definitive diagnosis cannot be made using ultrasonography and radiography, examination using magnetic resonance imaging is indicated. A 7.5 MHz linear probe is used for exploration of the metacarpal area, the fetlock and the pastern. In the metacarpal area, DDFT tendinitis are usually secondary to a chronic desmopathy of the assessory ligament. In the fetlock and pastern areas, they are generally associated with tenosynovitis of the digital tendon sheath. Digital tenoscopy is indicated for cases where significant abnormalities are not seen on ultrasonographic images. :