"Flexor tendon tenosynovitis" is a hallmark feature of
High-Yield Explanation
Flexor tendon tenosynovitis is a frequent hallmark of RA and leads to decreased range of motion, reduced grip strength, and "trigger" fingers. Progressive destruction of the joints and soft tissues may lead to chronic, irreversible deformities. Ulnar detion results from subluxation of the MCP joints, with subluxation of the proximal phalanx to the volar side of the hand. Hyperextension of the PIP joint with flexion of the DIP joint ("swanneck deformity"), flexion of the PIP joint with hyperextension of the DIP joint ("boutonniere deformity"), and subluxation of the first MCP joint with hyperextension of the first interphalangeal (IP) joint ("Z-line deformity") also may result from damage to the tendons, joint capsule, and other soft tissues in these small joints. Reference: Harrison&;s Principles of Internal Medicine; 19th edition; Chapter 380; Rheumatoid Ahritis