Figure 1  .

(A) Condylar cartilage in a healthy subject (transverse scan with a 7.5 MHZ linear transducer at the superior margin of the patella). Cartilaginous band is homogeneously hypoechoic with sharp inner and outer margins. (B) Normal appearance of finger flexor tendons (longitudinal scan with a 13 MHZ transducer). Note the typical fibrillar texture. (C) Median nerve in a healthy subject (longitudinal scan with a 13 MHZ transducer). Nerve echotexture is characterised by subtle, discontinuous hyperechoic bands on a hypoechoic background. This fascicular pattern can easily be differentiated from the fibrillar pattern of tendons. (D) Popliteal cyst in a patient with chondrocalcinosis (longitudinal scan with a 13 MHZ transducer).The small echoic (white) spots on the background of the anechoic (black) synovial fluid can be regarded as aggregates of calcium pyrophosphate dihydrate crystals. (E) Rheumatoid arthritis (longitudinal dorsal scan of a metacarpophalangeal joint with a 13 MHZ linear transducer). Note the joint space widening and the small erosion of the metacarpal head. (F) Small, superficial popliteal cyst (longitudinal scan with a 20 MHZ sector transducer) with clearly evident polipoid synovial hyperthrophy.