3 illnesses of the skeletal system:
1. OSTEOMYELITIS - is bone inflammation that often results from bacterial infection, and it can lead to complete destruction of the bone.
2. OSTEOMALACIA- or the softening of the bones, resulting from calcium depletion from bones.
3. OSTEOGENESIS IMPERFECTA- a genetic disorder producing very brittle bones that easily fractured, occurs because insufficient collagen or abnormal collagen is formed.