boutonniere deformity

(redirected from Boutonnière and swan-neck deformities)

bou·ton·nière de·for·mi·ty

flexion of the proximal interphalangeal joint with hyperextension of the distal interphalangeal joint of the finger, caused by separation of the extensor hood and protrusion of the head of the proximal phalanx through the resulting "buttonhole"; can result from degeneration (rheumatoid arthritis) or trauma.
A popular term for flexion of the proximal interphalangeal PIP joint and hyperextension of the DIP, caused by the detachment of the extensor tendon from the middle phalanx, volar displacement and resultant action as a flexor, associated with SLE, Jaccoud’s—post-rheumatic fever arthritis, rheumatoid arthritis, and camptodactyly

bou·ton·nière de·form·i·ty

(bū'tō-nyer' dĕ-fōrm'i-tē)
Rupture of the central slip of a digital extensor tendon at the middle phalanx, marked by extension of the metacarpopophalangeal and distal interphalangeal joints and flexion of the proximal interphalangeal joint.
[Fr., buttonhole]