Ultrasound is playing an increasingly important role in the differential diagnosis and monitoring of rheumatoid arthritis (RA) and psoriatic arthritis (PsA). This technique is more sensitive and specific than clinical examination to detect active synovitis, and the identification of specific synovitis patterns enable differentiation of PsA from RA and other entities. Ultrasound verified inflammation changes along with clinical improvement during therapy, and ultrasound was shown to predict future clinical and structural outcomes thus complementing the clinical risk assessment of patients. In the present review, we summarised the scientific evidence published in 2017 focussing on the use of ultrasonography for clinically relevant and pragmatic aspects of diagnosis and management of RA and PsA.