Rotational deformity of the index finger caused by reversed finger sucking.

Five patients with deformities of the index finger are presented. We believe all five are due to finger sucking. The deformity usually consists of a combination of rotation, radial deviation in the metacarpal phalangeal joint, and hyperextension in the proximal interphalangeal joint; one of these is more pronounced. In our series the rotational deformity and deviation were the most prominent features. Cause, incidence, and other factors influencing this deformity as well as spontaneous regression and therapy are discussed.