SKULL conditions

Question 1

Refers to the premature closure of the cranial sutures. The skull shape then undergoes characteristic changes depending on which suture(s) close early.

Most occur as isolated anomalies but syndromic associations can be seen in a small proportion of cases (~10%):

Answer 1

Craniosynostosis
(M>F)

acrocephalosyndactyly/acrocephalopolysyndactyly types

Apert syndrome

Carpenter syndrome

Crouzon syndrome

choanal atresia

Question 2

Secondary craniosynostosis occurs in relation to a variety of causes:

(Primary forms are either sporadic or familial)

Answer 2

endocrine disorders
- hyperthyroidism
- hypophosphataemia
- vitamin D deficiency
- hypercalcaemia

haematologic disorders causing bone marrow hyperplasia
- sickle cell disease
- thalassaemia

inadequate brain growth
- microcephaly
- shunted hydrocephalus

Question 3

which sutures close first - in order

Answer 3

metopic: 3-9 months
anterior fontanelle: 18-24 months
sphenosquamosal: 6-10 years
sphenofrontal: approximately 15 years
occipitomastoid: approximately 16 years
sagittal: approximately 22 years
coronal: approximately 24 years
lambdoid: approximately 26 years
squamosal: approximately 60 years

Question 4

Most common types

Answer 4

Sagittal > coronal >lambdoid > metopic

brachycephaly: bicoronal and/or bilambdoid sutures

scaphocephaly/dolichocephaly: sagittal suture

plagiocephaly: unilateral coronal and lambdoid sutures

frontal plagiocephaly: unilateral coronal suture

occipital plagiocephaly: unilateral lambdoid suture

trigonocephaly: metopic suture

pachycephaly: lambdoid suture

oxycephaly/turricephaly: sagittal, coronal and lambdoid sutures (tower like skull)

cloverleaf skull/Kleeblattschädel: intrauterine sagittal, coronal, lambdoid sutures (most severe)

harlequin eye: ipsilateral coronal suture

progressive postnatal pansynostosis: a rare form of craniosynostosis which involves late (postnatal) fusion of all cranial sutures 9

The sagittal suture is most commonly involved (≈50%), where the lateral growth of the skull is arrested while anteroposterior growth continues, producing a narrowly elongated skull known as scaphocephaly (meaning boat-shaped) or dolichocephaly (from the ancient Greek for long, δολιχός: dolichos).

The next most common sutures in terms of involvement are:

coronal (~20%)

lambdoid (~5%)

metopic (~5%)

Question 5

characterised by benign overgrowth of the inner table of the frontal bone. The aetiology is unknown. The condition is generally of no clinical significance and an incidental finding. It is typically bilateral and symmetrical and may extend to involve the parietal bones. The skull thickening may be sessile or nodular, and may affect the bone in a focal or diffuse manner.

Answer 5

Hyperostosis frontalis interna

Question 6

Hyperostosis frontalis interna is part of the triad of ? syndrome and may be encountered in a number of other syndromes.

Answer 6

Morgagni