Learn about how a baby’s bones change over time.
Cartilage is more flexible than bone and is able to resist compression and provide support and flexibility.
Instead, cartilage contains the chemicalchondroitin, which keeps it flexible and elastic.
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Cartilage also does not contain blood vessels or nerves.
Instead, blood flow and pain sensations come from the surrounding structures.
Over time, much of the cartilage in a child’s body hardens into bonea process called ossification.
Ossification actually begins in utero around the sixth or seventh week of gestation and continues through a persons mid-20s.
There are two types of bone ossification.
A baby is born with bones and cartilage that will eventually ossify into these stronger bones.
Long bones evolve through endochondral ossification.
Long bones are typically tubular, and they are longer than they are wide.
The arms and legs are made up primarily of long bones.
Short bones also evolve through endochondral ossification, but they are not structurally similar to long bones.
Flat bones evolve through intramembranous ossification.
The process takes place from before birth until a person is an adult.
Fontanelles are the spaces between the bones.
They are covered by membranes that protect the underlying tissues and the brain.
The anterior fontanelle(soft spot) remains soft until a child is about 2 years of age.
The posterior fontanelle usually closes by about 3 months of age.
When this happens, as a babys brain grows, its skull can become misshapen.
It occurs in one in 2,500 births in the United States.
Oftentimes, surgery allows space for the brain to grow properly.
The curves allow for proper mobility as we walk, bend, twist, and do everyday movements.
However, our spines do not start out with these curves.
A babys spine begins in simple a C-shape.
Scoliosis can be congenital or neuromuscular (a consequence of a muscular or neurological condition).
The treatment depends on the severity of the condition and can include observation, bracing, or surgery.
Spina bifidais a neural tube defect that affects the spine.
Spina bifida can result in physical and intellectual disabilities, but not everyone with spina bifida will have disabilities.
The causes of spina bifida are not completely understood.
Arms and Legs
Ossification of the long bones actually begins in the fetal stage.
Ossification of the limbs is not complete until the late teens to mid-20s.
Long bones in children are divided into four regions: diaphysis, metaphysis, physis, and epiphysis.
Only the metaphysis and diaphysis are present in adults.
The epiphysis is mostly cartilage in infants.
Over time, it gradually ossifies until it becomes almost completely replaced by bone in a persons late teens.
Rare Bone Disorders
Achondroplasiais a rare genetic bone disorder that prevents cartilage from being made into bone.
It causes a child to develop with short arms, legs, and a larger head.
The condition is a form of dwarfism.
People with achondroplasia have typical intelligence and life spans.
The condition is usually fatal before birth or shortly after.
Other Facts About Bones
Bones are a fascinating part of the human body.
A child’s bones are constantly changing, with bones developing into new, different bones all the time.
Being a positive role model is a great way to establish good habits in your kids.
Good nutrition and physical activity are the two factors that influence bone growth and health.
For the first year, your child will receive adequate nutrition through breast milk or formula.
The process of bones fusing is called ossification.
Ossification doesnt happen all at once.
When will my baby’s skull fuse?
A babys skull is made up of five bony plates.
The spaces between these bones are called the fontanelles.
The posterior fontanelle closes during the first few months of life.
The anterior fontanelle closes at around 1824 months.
A Word From Verywell
Your childs bones are changing and growing significantly during childhood and adolescence.
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