Objective To explore the clinical value of high frequency ultrasound in the diagnosis of nail damages and extensor tendon changes in patients with articular psoriasis ultrasound.Methods A total of 86 patients with psoriasis diagnosed in our hospital were analyzed retrospectively

including 46 patients with arthropathy psoriasis（PsA group）and 40 patients with psoriasis vulgaris（Ps group）. Thirty healthy subjects without nail damages in the same period were selected as the control group.All patients were examined by physical examination

and the general clinical data were recorded. The thickness of nail deck

nail bed

nail matrix and extensor tendon were measured by high frequency ultrasound. Wortsman classification was used to classify fingernails. Color Doppler ultrasound was used to evaluate the local inflammation of fingernails. The modified psoriasis severity index（mnapsi）was used to score the nail damage.The psoriasis area and severity index were used to evaluate the severity of psoriasis.The correlation between the thickness of nail deck nail bed and methyl substance measured by ultrasound and clinical data was analyzed.Results The severity of psoriasis in Ps group was higher than that in PsA group

but the inflammatory index in PsA group was higher than that in Ps group

there were significant differences（both P<0.05）. The thickness of deck

nail bed

methyl substance and extensor tendon in PsA group and Ps group were greater than those in control group. The differences were statistically significant（all P<0.05）. Type Ⅰ of Wortsman classification was common in Ps group（186 nails）

while type Ⅱ was common in PsA group（184 nails）. CDFI showed that the blood flow signals in nail bed

nail matrix and tendon of distal fingernail joint were significantly enhanced in PsA group and Ps group. The thickness of deck nail bed and methyl substance were positively correlated with mnpsi index in PS and PSA groups（r=0.34

0.208

0.517

P=0.024

0.025

0.009）;deck thickness was positively correlated with clinical psoriasis（r=0.305

P=0.018）.Conclusion High frequency ultrasound can evaluate the nail structures and morphologies in patients with psoriasis

it can reflects the local inflammations of nail beds

which has important value in the occurrence and development of arthropathy psoriasis.