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YOUR BABY’S HEAD
Wynken and Blynken are two little eyes
And Nod is a little head
And the wooden shoe
That sailed the skies
Is a wee one’s trundle bed.—Eugene Field,
“Wynken, Blynken, and Nod”
The top of the head is usually the first part of a newborn’s body to greet his or her parents. Next comes the face, which new parents tend to carefully scrutinize, seeking signs of familiar family traits. But a baby’s head looms large not only emotionally but physically as well. Indeed, a normal newborn’s head is disproportionately large compared to the rest of his or her body, taking up about of the body’s length.
An infant’s head is a remarkable piece of anatomy. The skull of the average baby is made up of 7 separate soft, pliable bones called head plates, which fit together like a jigsaw puzzle and are connected by fibrous membranes called cranial or skull sutures. There are spaces between the bones where the sutures intersect, which are medically known as fontanelles (also spelled fontanels), and more commonly called soft spots.
A newborn baby has 6 of these soft spots, located at the top, sides, and back of the head, but only 2 are noticeable—a large diamond-shaped one at the top of the head (anterior fontenelle) and a tiny triangular one at the back of the head (posterior fontanelle).
Both skull sutures and fontanelles play critical roles during pregnancy and after birth. During pregnancy they expand, allowing the baby’s developing skull to grow. They also give the baby’s skull the necessary flexibility to make the sometimes treacherous journey headfirst through the mother’s narrow birth canal. Then, after the infant is born, they enable the skull to expand to make room for the baby’s rapidly growing brain. Finally, the membranes covering the fontanelles protect the vulnerable brain.
Many parents worry needlessly about touching their babies’ soft spots because they believe these spots are very delicate and that their babies’ brains are prone to injury. But the membranes covering a baby’s fontanelles are, in fact, extremely tough and quite impenetrable. And underneath the soft spots, fluid surrounds and protects the brain.
The size of a baby’s soft spots and when they close vary tremendously. On average the one on the back of the head (posterior) is smaller— usually less than inch wide—and it typically closes when the baby is between 1 and 2 months old. The fontanelle on top of the head (anterior) is about 1 inch wide, and it tends to close between the ages of 7 and 19 months. Interestingly, this fontanelle sometimes increases in size during the first few months. The fontanelles of boys tend to close before those of girls.
Bulging Soft Spots
Q: Our baby’s soft spot on the top of her head sometimes bulges out. Should we worry?
A: It’s not unusual for a baby’s soft spots to bulge when he or she is lying down, crying, or vomiting, but when the baby is picked up and calmed down, the bulging should disappear. If your baby has a soft spot that always bulges, it may be a warning sign of several serious conditions. For example, a bulging soft spot can signal an excess intake of vitamin A. Other signs of vitamin A excess may include drowsiness and vomiting.
A bulging fontanelle can also be a warning sign of increased pressure in the baby’s brain from infections such as meningitis, encephalitis, or even Lyme disease. Or it may signal an endocrine, metabolic, or cardiovascular disorder; a brain tumor; or hydrocephalus, which is more commonly called “water on the brain” (see Large Soft Spots and A Large Head, below). Although a baby with these conditions is likely to have other more serious signs, it’s still important to report a bulging soft spot to your baby’s doctor as soon as possible.
Sunken Soft Spots
Q: I heard that if your baby’s soft spots are sunken, you should bring him to the emergency room. Is that true?
A: Not always. Sunken fontanelles may be totally normal and nothing to worry about. But they can also be a danger sign of serious dehydration, especially in a baby who has, or recently had, diarrhea and/or vomiting. Other signs of dehydration include sunken eyes, lack of skin elasticity, decreased urine output, and lethargy. Dehydration in a baby is life-threatening and requires emergency treatment.
An Extra Soft Spot
Q: Our infant son seems to have 3 soft spots. Is this normal?
A: As mentioned earlier, only 2 of a baby’s 6 fontanelles are usually apparent. If you notice a third one between the one on top and the one on the back of the head, it may signal hypothyroidism (see Large Soft Spots, below), which, if untreated, can lead to growth retardation, mental disability, and other serious medical problems. The good news is that hypothyroidism, which used to be a major cause of mental retardation, is easily treated when caught early. It’s normally detected by the heel prick blood test that’s done routinely just after birth.
A third fontanelle is also sometimes found in infants with Down syndrome, but other more noticeable and recognizable facial signs are usually present with this genetic disorder.
Large Soft Spots
Q: The soft spot on the top of my daughter’s head is much larger than the spots were on my other kids’ heads. What does this mean?
A: If your baby seems to have a soft spot that looks excessively wide, it may be nothing more than a residual reminder that she was born prematurely, had a low birth weight, or was small for her gestational age. But enlarged fontanelles can also indicate the delayed closure of the skull bones, which may be an early warning sign of a number of serious disorders including hypothyroidism (see An Extra Soft Spot, above) and rickets. Rickets, a bone disease caused by vitamin D and calcium deficiencies, can cause growth retardation, soft bones, and bowlegs (see Chapter 7). Both nutritional conditions are medically treatable.
Large soft spots can be a warning sign of another bone disease, osteogenesis imperfecta, aka brittle bone syndrome (see Chapter 7). This genetic condition often results in multiple bone fractures in babies and small children. Other early signs may include blue or gray sclera (whites of the eyes), discolored teeth, and easy bruising. Although brittle bone disease is not curable, there are effective treatments for it, including medication, physical therapy, and sometimes surgery.
A wide soft spot sometimes signals hydrocephalus (see Bulging Soft Spots, above, and A Large Head, below). Although many babies with this condition also have enlarged heads, it’s not always the case. Hydrocephalus can be a very serious condition requiring immediate medical attention.
Large soft spots can also be a sign of several genetic conditions, including Down syndrome and achondroplasia, which results in dwarfism as well as other head, facial, and body abnormalities. The signs of these genetic disorders are usually immediately apparent at birth or soon after.
Small or Missing Soft Spots
Q: I don’t think our baby has any soft spots. Is that possible?
A: If you can’t feel your infant’s soft spots, or if they’re barely noticeable, it can be a sign that your baby’s head plates have fused prematurely. Medically known as craniosynostosis, this is a congenital disorder (present at birth). Although its cause is unknown, it’s thought to have a genetic component.
A baby with craniosynostosis may also have a misshapen head (see Misshapen Heads in Older Babies, below) or a small head, referred to as microcephaly (see A Small Head, below). Craniosynostosis is potentially a very serious condition: When the skull sutures close prematurely, the brain doesn’t have enough room to grow. As a result, the child can suffer from mental and/or developmental deficiencies, as well as eye and other serious disorders. Surgery is usually necessary to correct craniosynostosis.
SKULL SHAPES AND SIZES
An infant’s head has to be very flexible to make room for the baby’s rapidly growing brain. But the down side to having a malleable skull is that it can easily become misshapen. Indeed, misshapen heads, or skull deformations as they’re medically called, are extremely common in infants, affecting about 1 in 3.
Babies can have any number of unusual head shapes. For example, some babies are born with cone-shaped heads, and others may have skulls that flatten during infancy. The shape and size of a baby’s head can be the result of some underlying genetic or other disorder, the birth process, or even environmental or other factors encountered during early infancy. Clearly, babies born with grossly distorted skulls have serious medical problems, but many atypical skull shapes and sizes are much more subtle and may or may not be cause for concern.
Q: My husband and I are very upset because the top of our newborn’s head is more pointy than round. What does this mean, and will his head ever look normal?
A: Many parents are dismayed to find that their newborns arrive into the world looking more like a member of the Conehead family, from the old Saturday Night Live skit, than a member of their own family. While often upsetting to the new parents, this type of skull deformation— called molding—is the most common one found in newborns. Molding is the result of the natural birth process, which forces a baby’s head through the cervix and out the vagina. It most frequently occurs in first births; breech births; forceps- and vacuum-assisted births, when there is prolonged labor; and when the mother’s uterus is small or otherwise abnormally shaped. The good news is that although your son’s head may look weird or scary, it’s usually a benign, temporary state. In a few months his skull will likely take on a normal oval shape.
A Long, Narrow Head
Q: I know many babies are born with cone-shaped heads, but rather than being long from top to bottom, my grandson’s skull seems elongated from front to back. Should we be concerned?
A: If a baby’s head looks long and narrow when viewed from the top, it can be a sign of molding after birth (see Cone-Shaped Head, above), especially if he was born prematurely. A boat-shaped skull, as it’s sometimes described, is quite common in premature babies. Medically known as scaphocephaly (from the Greek word for “small sailing vessel” or “rowboat”) or dolichocephaly (from the Greek word for “long”), it’s often due to the recommended practice of placing premature babies on their stomachs (prone) to sleep rather than their backs (supine). While it’s considered dangerous for full-term babies to sleep on their stomachs (see A Flattened Head, below), the prone position is the safest for premature infants.
A long, narrow head can also be a warning sign of craniosynostosis, the condition in which a baby’s skull plates fuse prematurely (see Small or Missing Soft Spots, above, and Misshapen Heads in Older Babies, below). In this case, surgical treatment is usually necessary.
A Flattened Head
Q: When we adopted our daughter at birth she had a perfectly shaped head, but now the back of her skull looks flat. What could have caused this and will it permanently affect her looks?
A: A flattened head that develops after birth, as in your daughter’s case, is extremely common in infants. Medically known as plagiocephaly (aka flat-head syndrome), it’s most often a sign of prolonged external pressure on a baby’s head. The baby’s face may also have a slightly asymmetric or lopsided look, and you may notice bald spots on the flattened side of the head (see Chapter 2).
While this may sound ominous, it’s usually a good sign that a baby is sleeping in the safest position—on his or her back (supine). This type of flattening is medically categorized as positional molding or deformational plagiocephaly. Although the flattening usually affects only one side of the head, it’s sometimes seen on both.
A flattened head can also be a telltale sign that a baby is spending too much time playing on his or her back or sitting in the same position in an infant carrier or car seat. In fact, by the time the average infant in the United States is 2 months old, he or she has spent more than 700 hours lying on a firm bed or other hard surface. If the flattening is due to an infant’s sleeping or sitting position, it’s most likely a benign, temporary condition. While it may be a cosmetic concern, the skull will usually regain its normal shape when the baby is more mobile in a few months.
However, there are some instances when a flattened skull is cause for medical concern. If your baby’s head is flattened on one side and he or she also tends to tilt his or her head in that same direction (for example, when held upright or during sleep), it may signal torticollis or—as it’s more commonly known—wryneck. Because babies with this condition usually sleep with their head on one side, this favored side of the head flattens. Interestingly, a flattened head can also cause wryneck. It’s not always easy to tell which comes first, the flattened head or the wryneck.
When a baby’s flattened head is related to wryneck or the flattening is extreme, a doctor may recommend physical therapy, or cranial orthotics. These skull-molding helmets are most effective when used between the ages of 4 and 12 months. Surgery is rarely, if ever, necessary.
Misshapen Heads in Older Babies
Q: I heard that if a baby’s head remains misshapen or flattened after 2 months, it can be a bad sign. Is that true?
A: Unfortunately, in many cases this is true. When a baby’s head remains abnormally shaped for longer than a few months, it can be a sign of craniosynostosis, a potentially serious condition in which the head sutures fuse prematurely (See Small or Missing Soft Spots, above). The more sutures involved, the more serious the condition.
When this happens, a baby’s growing brain pushes the skull out of shape. The resulting shape depends on which sutures, and how many, fuse too early. As mentioned previously, if the brain doesn’t have enough room to grow properly, excess pressure can build up inside the baby’s skull, leading to mental and developmental retardation. The pressure can also build up in the eye orbit, causing permanent eye damage. Because of the potentially serious effects of craniosynostosis, surgery is usually necessary.
A Large Head
Q: I know babies are supposed to have large heads. But my baby’s head seems bigger than other babies’ heads. Does this mean there’s something wrong with him?
A: Babies have large heads in proportion to the rest of their bodies— usually of the length of their bodies. In a healthy baby, the average head circumference is 13 to 14 inches, which is usually about equal to the circumference of the baby’s chest. A larger-than-normal head (above the 98th percentile) is referred to as macrocephaly. Large heads sometimes run in families, medically known as familial macrocephaly. This condition is usually nothing to worry about and doesn’t require treatment.
From the Trade Paperback edition.