Deformational plagiocephaly, brachycephaly, and scaphocephaly- common terminology.

Deformational Plagiocephaly

Deformational cranial flattening can take many forms, depending on the position of the infant’s head during the first few monthsof life. Most clinicians incorrectly refer to any type of cranial flattening as plagiocephaly, but this is not always correct. Plagiocephaly is derived from the Greek plagios meaning oblique or slanted, and kephale, meaning head. Thus,

the term deformational plagiocephaly is correctly applied to describe only flattening that is on one side of the head. Deformational plagiocephaly occurs primarily in infants who consistently favor turning their head to one side, that is, those with congenital muscular

torticollis (CMT). The resultant cranial shape has been compared with a parallelogram[;18 however, the frontal bossing is never equal to the degree of occipital flattening, and thus, the shape is really more trapezoidal. Asymmetric growth of the head often is accompanied by facial asymmetry, specifically an anterior shift of the ipsilateral forehead, ear, and cheek. Asymmetric opening of the palpebral fissures can also be observed as a consequence of the sagittal displacement of the ipsilateral zygoma. As asymmetric occipital flatten-

ing progresses, forward movement of the zygoma and attached lateral canthus on the affected side effectively shortens the distance between the medial and lateral canthal tendons. As a result, tension is reduced on the tarsal plates, and the eye appears more open on the side of the flattening. The vertical palpebral asymmetry can be easily confused with contralateral eyelid ptosis, and is termed pseudoptosis. Deformational plagiocephaly must be distinguished from 2 types of craniosynostosis that also can cause an asymmetric head shape: unilateral coronal synostosis (UCS) and lambdoidal synostosis. Both conditions are rare compared with deformational flattening.

Deformational Brachycephaly

Brachycephaly (Greek brachy, meaning short) denotes symmetrical occipital flattening and compensatory parietal widening. Infants with deformational brachycephaly (DB) have little or no rounding on the back of the head and appear to have a disproportionately wide orBbig[ head viewed from the front. The posterior vertex may appear taller than the front (turricephaly), giving a sloped appearance to the head in profile. The ratio

of cranial width to length, termed the cranial index or CI, is generally higher than normal. This figure was historically 0.75 to 0.80 in North America, although some observers suggest that the normal CI has risen to 0.8 to 0.85 in response to back sleeping. Most children with DB also have some element of concurrent asymmery, or plagiocephaly. The combination effect, which I refer to as asymmetric brachycephaly, is the most common type of deformational shape. Brachycephaly can also be seen in infants with craniosynostosis when both coronal sutures are fused. Synostotic brachycephaly is relatively rare and has features not seen in DB: severe forehead retrusion such that the superior orbital rim is behind the anterior surface of the globe (eyes appear very prominent) and anterior turricephaly.

Deformational Scaphocephaly

Deformational scaphocephaly (DS) (boat-like head) is an

uncommon variant of plagiocephaly. It is more commonly seen in infants who have extreme head rotation to one side or in premature infants who are positioned side-to-side in the intensive care units. Flattening develops on the side(s) of the head, and compensatory expansion occurs in the anterior and posterior cranium. Unlike typical plagiocephaly, this type of flattening is present up the side of the head rather than in back and can be challenging to detect. These infants tend to develop a long, slender head, and there is often very pronounced facial asymmetry. In fact, many parents voice concern over the notable facial, forehead, and ear asymmetry, and often do not appreciate the cranial flattening. This type of head flattening can be confused with scaphocephaly caused by premature fusion of the sagittal suture, but can be easily distinguished by proper clinical exam. Unlike DS, sagittal synostosis typically results in bilateral frontal bossing, bilateral occipital/parietal narrowing posterior to the anterior fontanelle, and decreased vertical height of the posterior cranium. Facial asymmetry is rare in sagittal synostosis. Additionally, most infants with this type of craniosynostosis have a head circumference in excess of the 90th percentile.