In rheumatoid arthritis (RA) patients, the diagnosis of Carpal tunnel syndrome (CTS) was made based on clinical findings and physical examinations. Then, the cross-sectional areas of the participants' median nerves from different levels were measured. Meidolateral and anteroposterior diameter were measured at the level of the carpal tunnel inlet. Flattening ratio was calculated. wrist to forearm ratio and wrist to forearm difference were calculated. The obtained data were compared between RA with CTS, RA without CTS and healthy control.

Inclusion Criteria:

• RA patients identified according to the 2010 American College of Rheumatology/Europan Leage Against Rheumatism classification criteria
• healthy controls (HC) with no history of rheumatic diseases and CTS.
• Individuals aged 18-65 years.

Exclusion Criteria:

• thoese with hypothyroidism,
• gout,
• diabetes mellitus,
• history of CTS surgery,
• upper extremity plexopathy,
• polinöropathy,
• uncontrollable fibromyalgia,
• steroid injection for CTS
• For the HC group, those with phalen or tinnel detected in at least one wrist and those with bifid median nerve detected during US evaluation were not included in the study.

RA patients identified according to the 2010 American College of Rheumatology/Europan Leage Against Rheumatism classification criteria healthy controls (HC) with no history of rheumatic diseases and CTS.