Background: Despite the progress made in the study of psoriasis and psoriatic arthritis, their early diagnosis and treatment for practicing physicians continue to be a difficult problem. Material and methods: 100 people were examined, including 70 patients with psoriatic arthritis aged between 18 and 60 years (23 men and 47 women), admitted to the rheumatology and arthrology departments of the Timofei Mosneaga Republican Clinical Hospital 2019-2022 (Favorable opinion of the Committee for Research Ethics, No 21 of 21.12.2019). The control group included 30 people with rheumatoid arthritis. Results: Ultrasound signs of damage to the joint structures were detected, such as synovitis (p=0.26), cartilage changes (p=0.433), enthesopathy (p=0.980) and tenosynovitis, statistically significant differences (p=0.800). Magnetic resonance imaging determined that fluid was the predominant symptom in frequency (n=13, 92.86%), including in the small joints of the hands (n=1, 100%) and feet (n=2, 100%). Conclusions: In large joints, the proliferation of the synovial membrane was detected in 51.67% of the joints and had predominantly high echogenicity. At small joints, synovial proliferation with predominantly low echogenicity occurred only in 6.1% of the joints.