Congenital club foot in the human fetus. A histological study.

Five club feet and three normal feet of fetuses aborted at sixteen to twenty weeks of gestation were studied by making serial histological sections cut in the sagittal, frontal, and transverse planes. In the club feet we found gradations in the severity of the following abnormalities: 1. Altered shape, size, and relationships of the tarsal bones. 2. Decrease in the size and number of fibers in the distal third of the muscles of the posterior and medial aspect of the leg; increased fibrous connective tissue in these muscles, their tendon sheaths, and the adjacent fasciae; and shortening of the triceps surae. 3. Thickening of the distal parts of the tendo archillis and of the posterior tibial tendon. 4. Ligaments on the posterior and medial aspects of the ankle joint pulled into the joint by the severe plantar flexion and varus displacement of the talus, and marked shortening and thickening of the tibionavicular and plantar calcaneonavicular ligaments. On the basis of these pathological findings, the possibility of a retracting fibrosis as the primary etiological factor of the club-foot deformity should be considered.