[Ultrasound diagnosis of the Achilles tendon]

Due to the superficial position of the Achilles tendon and the development of high-resolution probes with 7.5, 10, and more MHz, which allow the exact depiction of even very small structures, ultrasonography is the method of choice for the diagnosis of acute and chronic Achilles tendon disorders. Using sonography, both chronic achillodynia (disorders of the tendon itself, peritendinous tissue, bursa, and insertion of the tendon at the calcaneus) and ruptures of the Achilles tendon are exactly diagnosed. By sonographic examination, depiction of changes of the tendon itself (rupture, calcification, thickening) and evaluation of the peritendinous soft tissue with dynamic assessment of the gliding sheath are possible. The risk for the less experienced clinician using ultrasonographic assessment of the locomotor system is not to miss pathologic findings, but to overestimate them, due to artifacts. Sufficient knowledge of ultrasound physics as a reason for typical artifacts and the use of a standardized examination technique are necessary. However, by using high-resolution small ultrasound probes, the depiction of "problem areas" (e.g., musculotendinous junction, insertion of the tendon on the calcaneus) has become easier and more accurate.