The aim of this observational study is to establish normal thermographic parameters in patients with rheumatoid arthritis, in order to prevent and diagnose rheumatic foot using thermography. The main question to be answered is: What are the normal thermographic parameters in rheumatic foot?

If there is a comparison group: the researchers will compare the thermography of the foot in healthy subjects and in subjects with rheumatoid arthritis to see if there are any alterations in the thermographic image.

Patients who wish to participate in the study will undergo a thermographic study of the foot, which does not entail any risk to their health.

Inclusion Criteria:

• Patients with rheumatoid arthritis of more than 5 years' duration
• Healthy patients without diagnosed systemic disease
• Patients between 40 and 80 years of age

Exclusion Criteria:

• Patients who are pregnant or may become pregnant
• Patients with degenerative diseases or significant cognitive impairment
• Patients with rheumatic diseases without a diagnosis of rheumatoid arthritis

Selected patients will be healthy subjects and subjects with more than 5 years of rheumatoid arthritis who wish to voluntarily participate in the study.