Rickets in a 6-month-old monkey.

A 6-month-old male monkey with rickets was found dead by its keeper. Radiographic studies showed osteopenia of the entire skeletal system, a cup-shaped concavity and poor mineralization of metaphyseal ends, and markedly widened and irregular epiphyseal growth plates of the long bones and ribs. Gross anatomic findings included bowing abnormalities and microfractures in the radius, ulna, tibia, and fibia, and enlarged and widened cartilage columns extending into the metaphyses in the long bones and ribs. Histologic features included deficient mineralization and irregular disordered columns of proliferating cartilage in growth plates extending into other zones, dilated vascular channels, and poor mineralization of chondroid and osteoid tissues.