he pattern of physical development during infancy

Weight 

At the age of 4 months, baby weight usually increased 2-fold. At the age of 1 year baby weighs an average of 3 times the weight at birth, or about 21 pounds. At the age of 2 years the average weight of American babies is 25 pounds. Increased body weight during infancy mainly due to an increase in fat tissue. 

High 

At the age of 4 months of infant size between 23 and 24 inches, at the age of 1 year between 28 and 30 inches, and at the age of 2 years between 32 and 34 inches. 

The proportion of physical 

Reduced head growth in infancy, while the growth of body and limbs increase. So the baby gradually became less weight on top and looks more slender and not stocky at the end of the baby. 

Bone 

The amount of bone increases during infancy. Hardening of the bones begins early in the first year, but not finished until puberty. Crown area of ​​the brain or soft 50% of babies born have been closed at the age of 18 months, and almost all babies have been closed at the age of 2 years. 

Muscle and fat 

Uric-existing muscle at birth but in the form of growing. Vein-muscle grew slowly during infancy and weak. In contrast, fat tissue is growing rapidly, partly due to high levels of fat in the milk which is the staple food for babies. 

Build the body 

During the second year, when the body proportions changed, the baby began to show a characteristic tendency of the body wake. 3 the shape of the body most prevalent is ektomorfik, which tend to be long and slender, endomorfik, which tend to be round and fat, and mesomorfik, which tend to be heavy, hard, and 4 rectangles. 

Tooth 

Average of 4 to 6 babies have milk teeth at the age of 1 year and 16 at the age of 2 years. The first tooth emerges is the front teeth, while the latter is the jaw. The last four milk teeth usually appear until the first year of childhood. 

Nervous system 

At the time of birth, brain weight is one-eighth the total weight of the baby. The most rapid brain weight at age 2 years. Cerebellum, which are crucial to maintaining balance and body control, increased weight 3 times a year after birth. This applies also to a large brain. The cells are immature, that existed at the time of birth, continues to grow after birth but relatively few new cells are formed. 

The development of sensory organs 

At the age of 3 months, the eye muscles are coordinated enough to allow the baby to see things in a clear and real and cone cells are well developed to enable them to see colors. Hearing developed rapidly during this time. Smell and taste are well developed at birth, continued to improve during infancy. Babies are very responsive to all stimuli the skin due to their thin skin texture and because of all the sensory organs associated with touch, pressure, pain, and temperature is well developed.