This document discusses various abnormalities that can be seen on infant skull radiographs. It begins by describing normal ratios of cranium to facial bones at different ages. It then covers decreased and increased bone density, noting specific conditions they may indicate. Localized areas of defective ossification and focal sclerosis are also discussed. Variations in skull size like macrocephaly are addressed, as are abnormalities of head shape including faults from fetal positioning and different types of craniosynostosis.

1. Infant Skull RadiographInfant Skull Radiograph
A vault of information in theA vault of information in the
era of cross sectional imagingera of cross sectional imaging..
Dr. Hazem Abu Zeid YousefDr. Hazem Abu Zeid Yousef
Assisstant Professor of RadiodiagnosisAssisstant Professor of Radiodiagnosis..
Assiut UniversityAssiut University..

2. At birth, the volume of the neurocranium is
eight to nine times greater than that of the face
)3(.This ratio is 5:1 by 2 years, 3:1 at 6 years,
and 2:1 in the adult. A lateral skull radiograph
with the jaws closed reveals the relative areas in
the midsagittal plane of the cranium. The ratio of
cranium to facial bones is 4–4.5 at birth and
decreaseswith age: 3–3.5 at 2 years, 2.5 at 6
years, and 1.5–2 in the adult )3(.

4. Decreased Density:Decreased Density:
GeneralizedGeneralized
severe thinning of the calvaria andsevere thinning of the calvaria and
decreased calvarial density may signifydecreased calvarial density may signify
osteogenesisosteogenesis
imperfecta, achondrogenesis,imperfecta, achondrogenesis,
hypophosphatasiahypophosphatasia,,

5. hypophosphatasiahypophosphatasia

7. Osteogenesis ImperfectaOsteogenesis Imperfecta

9. Decreased Density: LocalizedDecreased Density: Localized
Localized areas of defective ossification occur inLocalized areas of defective ossification occur in
the lacunar skullthe lacunar skull..
True convolutional markings occur later, afterTrue convolutional markings occur later, after
sutural closuresutural closure..
The termThe term lacunar skulllacunar skull signifies a dysplasia ofsignifies a dysplasia of
the membranous bone with well-defined lucentthe membranous bone with well-defined lucent
areas in the calvaria that correspond to onossifiedareas in the calvaria that correspond to onossified
fibrous bone. The lacunae are bounded byfibrous bone. The lacunae are bounded by
normally ossified bonenormally ossified bone..

11. Increased Density:Increased Density:
GeneralizedGeneralized
The differential diagnosis for increased boneThe differential diagnosis for increased bone
density includes sclerosing bonedensity includes sclerosing bone
dysplasias such as osteopetrosis,dysplasias such as osteopetrosis,
pyknodysostosis, and craniodiaphysealpyknodysostosis, and craniodiaphyseal
DysplasiaDysplasia..

13. Increased Density: LocalizedIncreased Density: Localized
In the neonatal skull, the differentialIn the neonatal skull, the differential
diagnosis for focal sclerosis includesdiagnosis for focal sclerosis includes
frontometaphyseal dysplasia andfrontometaphyseal dysplasia and
craniometaphyseal dysplasiacraniometaphyseal dysplasia

15. Variations in Skull SizeVariations in Skull Size

17. MacrocephalyMacrocephaly

19. Abnormalities of Head ShapeAbnormalities of Head Shape
Faulty Fetal Packing
The term faulty fetal packing signifies
concave depressions in the neonatal skull
that are caused by prolonged extrinsic
pressure from a malpositioned limb in utero

21. CraniosynostosisCraniosynostosis
Normal skull growth occurs in a directionNormal skull growth occurs in a direction
perpendicular to the axis of the suturesperpendicular to the axis of the sutures..
When sutures fuse prematurely, headWhen sutures fuse prematurely, head
growth occurs along the axis of the fusedgrowth occurs along the axis of the fused
suturesuture..

22. CRANIOSTENOSIS = premature closure of sutures
(normally at about 30 years of age)Age:often present at
birth; M:F = 4:1
Etiology: A.Primary craniosynostosis
B.Secondary craniosynostosis(a)hematologic: sickle
cell anemia, thalassemia(b)metabolic: rickets,
hypercalcemia, hyperthyroidism, hypervitaminosis
D(c)bone dysplasia: hypophosphatasia,
achondroplasia, metaphyseal dysplasia, mongolism,
Hurler disease, skull hyperostosis, Rubinstein-Taybi
syndrome(d)syndromes: Crouzon, Apert, Carpenter,
Treacher-Collins, cloverleaf skull, craniotelencephalic
dysplasia, arrhinencephaly(e)microcephaly: brain
atrophy / dysgenesis(f)after shunting procedures

23. Types: Sagittal suture most commonly affected
followed by coronal suture 1.Scaphocephaly =
Dolichocephaly (55%)premature closure of sagittal
suture (long skull)2.Brachycephaly = Turricephaly
(10%)premature closure of coronal / lambdoid sutures
(short tall skull)3.Plagiocephaly (7%)unilateral early
fusion of coronal + lambdoidal suture (lopsided
skull)4.Trigonocephaly: premature closure of metopic
suture (forward pointing skull)5.Oxycephaly:
premature closure of coronal, sagittal, lambdoid
sutures 6.Cloverleaf skull =
Kleeblattschädel:intrauterine premature closure of
sagittal, coronal, lambdoid