Musculoskeletal ultrasound is a rapidly growing imaging modality used for the investigation and management of musculoskeletal disorders. The first report of musculoskeletal ultrasonography was published in 1958 by K. T. Dussik who measured the acoustic attenuation of articular and periarticular tissues including skin, adipose tissue, muscle, tendon, articular capsule, articular cartilage and bone (Dussik et al., 1958). It was first used in rheumatoid arthritis by Cooperberg in 1978 for the assessment of synovitis in the knee. (Cooperberg et al., 1978). De Flaviis made the first report of ultrasonography in the hand in rheumatoid arthritis in 1988, describing synovitis, tenosynovitis, and erosions (De Flaviis et al., 1988).The first application of power Doppler in demonstrating soft tissue hyperaemia in musculoskeletal disease was reported in 1994 by J. S. Newman (Newman et al., 1994). Since, power Doppler has started to replace gray-scale ultrasonography as an indicator of inflammatory joint disease. Ultrasonography has a number of advantages, including good patient tolerability and ability to scan multiple joints in a short period of time. Thanks to smaller high-frequency transducers that were better suited for superficial structures such as the small joints, many reports and studies have been published. However, there are scarce data regarding its validity, reproducibility, and responsiveness to change, making interpretation and comparison of studies difficult. In particular, there are limited data describing standardized scanning methodology and standardized definitions of ultrasonography pathologies.