(buttonhole deformity) a deformity seen in a finger when the central strand of the tendon of the extensor muscle of the digits is ruptured. This results in marked flexion of the middle phalanx across the proximal interphalangeal joint and hyperextension of the distal interphalangeal joint.... boutonnière deformity
a congenital abnormality of the scapula (shoulder blade), which is small and positioned high in the shoulder. It is caused by failure of the normal development and descent of this bone. [O. G. K. Sprengel (1852–1915), German surgeon]... sprengel’s deformity