Examining the head

Head Shape

Children’s heads, like those of adults, come in a wide range of sizes and shapes. The variation is greatest in younger infants because newborns have pliable heads. The intense pressures applied during vaginal delivery mold the head. Most babies enter the world “occiput first” (occiput anterior), resulting in marked occipital prominence. Overlapping of some skull bones is common. The head remolds spontaneously within days. Premature infants have characteristic head shapes, flattened along the temporal aspects, leading to a long, narrow appearance due to the increased pliability of their bones.

The newborn skull examination includes careful palpation of the entire skull. Meticulously follow each suture with a finger. Two common abnormalities resulting from birth pressures may be present: caput succedaneum and cephalhematoma. A caput succedaneum is a diffuse area of edema over the presenting part of the head. It does not follow any bony landmarks. A cephalhematoma is a subperiosteal hemorrhage, usually found over the parietal bones posteriorly. When present bilaterally, it appears as though the child has two horns. These hematomas heal partly through ossification, which starts around the edges where the periosteum has been lifted away from the skull. Parents need considerable reassurance because a cephalhematoma feels, on palpation, like a hole in the bone surrounded by a hard ridge around the base. Cephalhematomas are harmless, never cross suture lines, and may take many months to resolve.

Since implementation of the successful Back to Sleep campaign to decrease sudden infant death syndrome (SIDS), it is not uncommon to encounter young infants with markedly flattened occipital bones. In other infants, asymmetric flattening develops as they lie with the head turned to one side or the other, preferentially toward the main light source, for example, a window. Parents must be encouraged to spend “tummy time” with their infant (i.e., supervised prone positioning for short periods several times a day while the infant is awake). Infants with lateral skull flattening must be examined carefully to rule out any tightening of the sternocleidomastoid muscle or other neck mobility anomaly. By alternating placement of infants in their cribs, pressure on the soft infantile skull bones will spontaneously be distributed more evenly in most cases, which allows for remodeling. In the final analysis, the most powerful factor in the spontaneous improvement or resolution of postural cranial distortion is the child’s assumption of the upright posture.

Brain growth is the prime determinant of head size. Other important factors include genetic influence, intracranial pressure, and bony abnormalities. Hydrocephalus, that is, the abnormal accumulation of cerebrospinal fluid, leads to increased intracranial pressure and rapid expansion of the infant skull. Craniosynostosis, the premature closure of sutures, limits skull growth. Skull bones grow relatively independently, usually symmetrically, along the suture lines in a direction perpendicular to the lines.

Craniosynostosis of the sagittal suture limits the skull’s width. As a result, compensatory excess growth occurs along the anteroposterior axis and possibly in the height of the skull, which produces a scaphocephalic shape, that is, a long, narrow skull (Fig. 7-1). Premature closure of the coronal suture results in a tall, wide head. When a suture closes prematurely, a palpable firm bony ridge sometimes is present along the suture line. Do not confuse this finding with normally overlapped sutures that are felt soon after birth.

FIGURE 7-1 Measurement of head circumference in an infant. The tape should encircle the most prominent parts of the forehead and occiput.

Case History

The parents of a 10-day-old baby boy bring him in for evaluation because of lumps at the back of his head and extra soft spots. Joshua was delivered vaginally at 42 weeks’ gestation. The labor lasted 20 hours, and delivery was assisted by both vacuum extractor and outlet forceps. It has been difficult to establish breastfeeding, and Joshua is described by his first-time parents as crying excessively. Both grandmothers are present, and they are concerned that Joshua experienced brain damage from birth trauma.

The experienced clinician will try to establish the root causes for the family’s concerns. For example, the family may be comparing Joshua with another child who has cerebral palsy or developmental delays. It also is essential to give the parents the necessary space and permission to frankly discuss their feelings about the grandmothers’ concerns, the grandmothers’ acceptance of the parents’ decisions regarding pregnancy, delivery, and child rearing, and ongoing expectations for involvement of the grandmothers in key medical decisions regarding Joshua’s health.

There is a wide range of normal variation in head size and shape of normal babies at birth. Cephalhematomas and edema caused by vacuum extractors frequently are interpreted by brand-new parents as signs of skull fractures and brain trauma. The result is excessive anxiety and concern, which can lead to disturbed infant-parent bonding.

Many of the most common scalp and head shape anomalies are described in this chapter, with tips on how to distinguish the results of normal vaginal delivery pressures from signs of significant injuries.

Head Measurement

Accurate measurement of head circumference is surprisingly difficult. Measure the largest circumference possible by wrapping the tape around the most prominent parts of the forehead and occiput (Fig. 7-2). You should routinely take three measurements. If these measurements differ, you need to refine your technique. Even a slight variation in the position of the measuring tape changes the result significantly. Many infants and young children actively dislike head circumference measurement. Because a calm, cooperative child may become fretful, fearful, and oppositional when you attempt to obtain this measurement, it is best to leave it until the end of the examination. A parent’s assistance may be essential. I have found that the task is easier to accomplish when the infant is fed or cuddled and when the young child distracted with a toy or play activity.

FIGURE 7-2 A, Fontanels and bones of the newborn skull, viewed from above. B, Lateral view of newborn skull, showing fontanels and bones.

The head circumference measurement must be plotted on a standardized head circumference graph. As with all standardized charts and graphs, no single value represents a “normal” head circumference (see Chapter 3). Measurements of new immigrants from various ethnic and racial groups may plot in the lower percentiles. Remember that, by definition, 3% of the normal population will have head circumferences that are below the third percentile or above the ninety-seventh percentile.

Also, head sizes tend to follow familial patterns. Measure the head circumferences of both parents and be sure to enquire about grandparents or any family member with an unusual shaped or sized head. Family photographs found on cell phones have made assessment of familial patterns much easier for the clinician.

A single measurement of head circumference may identify significant microcephaly or macrocephaly. Of greater value is the pattern of growth over time. Accurate measurement and charting is critical. An increase in measurement from the 25th to the 75th percentile over a month may lead to early detection of hydrocephalus or to a distressed, angry family if either measurement is inaccurate. More importantly, computed tomography (CT) studies of the infant brain have been implicated in decreased cognitive and intellectual outcomes and increased lifetime risks of cancer. Diagnostic imaging of the young brain should be ordered only when there is reasonable evidence of a significant problem.

Fontanels

The fontanels are the gaps between bones in the infant skull where three skull bones meet (Fig. 7-2, A and B). Gentle palpation of the fontanels is a routine part of the newborn examination.

The posterior fontanel usually closes by 6 to 8 weeks of life. Closure of the anterior fontanel is much more variable and usually occurs between the ages of 12 to 18 months. In some infants, normal closure does not occur until age 24 months. Remember, variations in shape, size, and development are to be expected in children. Be very cautious about your body language and vocal tone when asking parents about the shape of their child’s head.

Four other fontanels are routinely present, though they rarely have an impact on clinical assessment: two anterolateral (sphenoid) fontanels where the coronal and squamosal sutures meet, and two posterolateral (mastoid) fontanels where the squamosal and lambdoid sutures meet. Occasionally the anterior fontanel seems to extend between the frontal bones. The metopic fontanel is actually a widening of the metopic suture. Other extra fontanels may be palpated. The parietal fontanels, that is, persistent parietal foramina, are located along the sagittal suture between the anterior and posterior fontanels. These symmetrical holes on either side of the sagittal suture once were mistakenly thought to be evidence of trephining by ancient Egyptians in well-preserved mummy skulls.

The anterior fontanel may vary in size from that of an adult fingertip to several centimeters in width and length. Persistent delays in closure or an unusually large size may indicate increased intracranial pressure or pathological delay in bone growth. When the posterior fontanel persists, hypothyroidism must be ruled out.

Increases in intracranial pressure, such as in meningitis, are reflected by changes in palpable tension of the fontanel and loss of normal venous pulsations (Fig. 7-3). A normal fontanel may feel full when the infant lays flat, cries, or struggles. It is best to assess anterior fontanel tension only when the infant is calm and held upright. With dehydration, the fontanel will appear sunken. Practice and palpation of dozens of fontanels will educate your fingers to detect abnormalities in size and tension. Each infant is his or her own standard. Serial assessments with careful descriptions of findings facilitate early detection of raised intracranial pressure.

FIGURE 7-3 Palpation of the anterior fontanel. For best results, the infant should be upright and calm.

Craniotabes

Craniotabes is the ability of the skull to indent under pressure and, like a ping-pong ball, to spring back into shape. This phenomenon is normal in infants, especially along the lambdoid sutures. Persistence of craniotabes past the first few months suggests inadequate bone mineralization, as is seen in persons with rickets.

Auscultation

Listen to the skull over the vertex, temples, and eyeballs. Soft bruits or flow noises are common in normal children. During febrile episodes, the noises tend to be louder. The presence of a harsh, loud bruit suggests an arteriovenous malformation or transmission of abnormal sounds from the heart or great vessels. Bruits are frequently a normal variant, so listen to as many skulls as possible to tune your ears to the range of normal noises.

Transillumination

See Chapter 4 for a detailed discussion of transillumination.

Hair

Characteristics of normal hair differ widely between ethnic and racial groups. Examination of hair includes distribution, loss, broken strands, texture, color, and variation from the family norm. The scalp also must be inspected to detect problems such as seborrheic dermatitis, psoriasis, or ectodermal dysplasia, which may affect the hair. Normal newborns may have a full head of soft, silky hair or be completely bald. Excess scalp and facial hair associated with facial anomalies may indicate a genetic syndrome such as cri du chat. Infants of diabetic mothers often have excess scalp and body hair compared with infants of nondiabetic mothers. Newborn hair tends to fall out by approximately 3 months and is replaced by hair that may differ markedly in texture, color, and distribution.

Young infants often lose hair over the occiput and other pressure points. Be aware of possible infant neglect and insufficient changes of position as causes of this hair loss. Patchy areas of loss may be associated with fungal infection or twirling or pulling of the hair (trichotillomania). Again, excess hair loss may indicate child maltreatment. Be cautious in your approach because many young children twirl the forelock as a self-soothing routine (a behavior frequently associated with thumb or finger sucking). An idiopathic cause of hair loss is alopecia areata. Focal loss of hair may be the result of head shaving in the neonatal intensive care unit, cultural and religious practices, or ectodermal defects. General hair loss may follow severe febrile illnesses, such as typhoid fever.

Extremely sparse, fine hair is associated with ectodermal dysplasia. Coarse hair is seen in persons with hypothyroidism. In Menkes syndrome, a degenerative neurologic condition that results in kinky hair, the hair shafts grow twisted and brittle, breaking off a few centimeters from the scalp. The abnormal hairs are called “pili torti.”

In persons who are severely malnourished, the hair becomes fine and brittle, and in persons who are black, it frequently changes to a reddish color. The same phenomenon is seen in children presenting with untreated HIV/AIDS. A white forelock may be seen in children with Waardenburg syndrome. This dominantly inherited condition is usually associated with deafness. Albinos lack pigment in their hair, skin, and irises, leading to teasing, bullying, and, at times, rejection by the family.

Hearing

Always ask parents if they have any concerns about their child’s ability to hear. Parents often suspect a hearing problem months before their child’s health care providers do. Audiologists are now able to measure hearing in infants from birth. The assessment of children with anomalies of the head and neck must always include formal hearing testing because the incidence of hearing problems is higher in children with such anomalies. Likewise, parental concerns about lags in language development should result in prompt audiologic evaluation. Delayed expressive language milestones may indicate hearing dysfunction (see Chapter 6).

Shape and Position

Start with a close inspection of the external ears. Are both present and normally formed, or do they fit the criteria for low-set ears? (See Chapter 5.) Do not be fooled by posteriorly rotated ears. If the vertical axis of the pinna is tilted posteriorly, the ear may appear to be low set. Minor anomalies of the ears such as skin tags, pits, or fistulas just anterior to the tragus are common and usually are of no major significance. Inspect and palpate the mastoid and postauricular areas. Gently move the pinna and tragus; any tenderness suggests otitis externa.

The Otoscope