Scurvy (Vitamin C Deficiency) — Wimberger's Ring

An 11-month-old infant on an exclusive processed-milk diet presents with pseudoparalysis of both lower limbs, swollen tender legs, and irritability. Examination reveals spongy bleeding gingivae, perifollicular hemorrhages with corkscrew hairs, and subperiosteal swelling of the distal femora. Knee radiographs demonstrate the classic scorbutic tetrad including generalized osteopenia, a dense transverse metaphyseal band (Frankel's line), a lucent submetaphyseal zone, and lateral metaphyseal beak-like projections. The structure marked **C** in the diagram shows a dense sclerotic ring encircling the epiphyseal ossification centers. Which of the following best describes the pathophysiological mechanism underlying the radiographic findings marked **C**?