Rickets and osteomalacia are diseases characterized by defective mineralization of bone. Rickets occurs in children and results from vitamin D deficiency or phosphate malabsorption, causing softening of the bones and deformities. Osteomalacia is the adult counterpart, also caused by vitamin D deficiency. Both present with bone pain and tenderness. Diagnosis is confirmed by x-rays showing bone abnormalities and lab tests showing low calcium and phosphate levels with high alkaline phosphatase. Treatment involves high dose vitamin D supplementation and calcium, with orthopedic management for bone deformities in severe rickets.