How many bones does a small child have?

A newborn baby is born with around three-hundred individual bones, but as they grow, many of these will fuse together. For example, newborn babies' skulls are not fully formed. A neonatal skull is composed of five plates of bone which will grow together to form the solid cranium in childhood. Similar fusion takes place in the elbows, ankles, and all throughout the body. Because anatomy is highly variable and any two children might have slightly different rates of skeletal maturation, it is difficult to say exactly how  many bones a small child has. 

Between the ages of two and three years, a child's bones will continue to ossify from soft cartilage into hard bone, and some of the bones will begin to fuse or close off. At this time, the number of bones in a child's body is still quite high--close to three-hundred. Between six and eighteen months of age, the skull has fused into one large piece of bone, so we can at least say that there are four less (unfused) bones in the body. The last stages of bone and growth plate fusion occur between the ages of sixteen and twenty-five, and at this time the number of bones is typically about two-hundred and six. My best guess, bearing in mind the high degree of variability from person to person, is that in the first five years of life, a child's body may have anywhere from 250 to 290 bones in it.