CONGENITAL AND INFANTILE CONTRACTIONS.
These are usually of paralytic origin, but include a proportion of cases of true hammer finger. The common form is that already described by Mr. William Adams (Medical Society, December 1890), in which the inter-phalangeal joints of one or more fingers (most frequently the fifth) are flexed, and the integument on the palmar aspect forms a longitudinal fold, which becomes tense when an attempt is made to straighten the digit; the metacarpo-phalangeal joint is super-extended. At first the finger may be fully extended by passive force, but after a few years the position of flexion at the first inter-phalangeal joint is rendered permanent by imperfect development of the ligamentous fascial and even cutaneous structures in front of the articulation, while the terminal phalanx usually remains more or less helpless. The condition is probably dependent upon an infantile paralysis of the flexors of the affected digit. The use of friction, passive movement, and electricity, may be of value in the early stages.