Briefly describe the characteristics of preschool children's bones.

Children have unique growth and development characteristics. Preschool children's skeletons possess the following distinct features: 1. Rapid cartilage development, with less bone mass compared to adults. However, bone cell activity is high, leading to fast bone mass increase. This makes their bones more susceptible to external influences and deformation. 2. High joint mobility; the joint surfaces are incompletely developed, and the cartilage covering the joints is incomplete. These factors contribute to greater joint flexibility but also increase the risk of dislocation. 3. Poorer bone quality, with lower bone density and a tendency toward osteoporosis, making bones more vulnerable to damage from external forces and prone to fractures. 4. Bone development is significantly influenced by environmental and nutritional factors. Adequate nutrition and sufficient physical activity are essential to support healthy skeletal development.