NORMAL SUTURES AND FONTANELLES

SUTURAL ANOMALIES - CRANIOSYNOSTOSIS

Normal sutures and Fontanelles
1 – Anterior fontanelle 2 – Coronal suture 3 – Sphenoid fontanelle 4 – Sphenoid suture 5 – Mastoid fontanelle 6 – Lambdoid suture 7 – Posterior fontanelle

Cranial Fontanelles

Large fibrous areas where sutures meet. Dense connective tissue membranes that act as fibrous joints connecting the cranial bones.

• Allow progressive growth of skull bones and underlying brain in the developing fetus.
• Permit moulding of the skull during fetal life and at delivery.
• Difficult to assess structural continuity of sutures and fontanelles with 2D ultrasound.
• Abnormal development in
• dysmorphic syndromes
• congenital syndromes
• chromosomal abnormalities
• delayed or premature closure of sutures.

3D Ultrasound
3D CT scan

Video link to 3D surface CT of normal anterior fontanelles and sutures

CRANIOSYNOSTOSIS

• Non specific deformity caused by premature closure of the cranial sutures. Depending on the sutures involved as well as the order and timing of the fusion a characteristic or unusual cranial shape results.
• Primary craniostenosis
• Isolated developmental error.
• Secondary craniostenosis
• Associated with chromosomal anomalies.
• Associated with metabolic disorders.
• Associated with hematologic disorders.
• Part of an inherited syndrome.

ULTRASOUND

1. Isolated sutures.
• Scaphocephaly / dolicocephaly) Long skull.
• Brachycephaly . Short broad skull.
• Trigonocephaly. Forward pointing skull
2. Multiple sutures.
• Plagiocephaly (coronal and lambdoid). Lopsided skull
• Oxycephaly (coronal sagittal and lambdoid)
• Cloverleaf skull (coronal and lambdoid).

Craniosynostosis + Facial Dysmorphology Or Limb Abnormalities

• Aperts Syndrome
• Carpenters Syndrome
• Pfeiffer Syndrome
• Saethre-Chotzen Syndrome

REFERENCES

1. Patel MD, Swinford AE, Filly RA. Anatomic and Sonographic Features of the Fetal Skull. J Ultrasound Med 1994, 13:251-257.
2. Pretorius DH, Nelson TR. Prenatal Visualization of Cranial Sutures and Fontanelles with Three-Dimensional Ultrasonography. J Ultrasound Med 1994, 13:871-876.
3. Meilstrup JW, Botti JJ, MacKay DR, Johnson DL. Prenatal Sonographic appearance of Asymmetric Craniostenosis. A case report. J Ultrasound Med 1995, 14:307-310.