In the course of rheumatoid arthritis, changes to tendons occur in different areas. This can lead to rupture if not prevented at an early stage. In particular, regions with extreme joint thickness, high mechanical wear and tear and narrow regions present a higher risk of synovitis. This primarily affects the tendons of the hand, where the extensor digitorum minimus tendon and the extensor and flexor pollicis tendons are most at risk. There is a high possibility of rotator cuff lesion in the shoulder area during the course of a secondary synovitis dependent raised shoulder, or by bursitis or tendonitis. A rupture of the biceps tendon is also increased by omarthritis or synovitis in the sulcus. For the foot, the posterior tibial tendon is most commonly effected, which if primarily or secondarily damaged can lead to a rheumatic flat foot. In addition, there can be partial or complete destruction in the Achilles tendon area, which is definitely pathognomonic. The narrow syndrome in the flexor hallucis and the extensor digitorum tendons are less common.