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Craniosynostosis and positional plagiocephaly
Premature closure of a cranial suture stops growth perpendicular to the suture and causes compensatory growth parallel to it — so head shape reveals the suture: sagittal gives a long narrow head, metopic a triangular forehead, and unicoronal a flat forehead and a "harlequin" orbit.
Why it matters in the exam
The sagittal suture is the commonest and gives scaphocephaly (a long narrow head); metopic — trigonocephaly with a forehead ridge and close-set eyes; unicoronal — flattening of the forehead on the same side, an elevated orbit ("harlequin" on radiograph) and deviation of the nasal root towards the affected side; bicoronal — brachycephaly, usually as part of a syndrome. The clinical diagnosis is confirmed with three-dimensional CT. Treatment for sagittal: endoscopic surgery with a helmet up to age 3 to 4 months, or open cranial vault remodelling at 6 to 12 months. Syndromes carry a higher risk of raised intracranial pressure, airway problems and eye problems, so they are treated by a craniofacial team.
The main syndromes: Apert (FGFR2) — bicoronal with complete syndactyly of hands and feet; Crouzon (FGFR2) — prominent eyes and midface hypoplasia without hand anomalies; Pfeiffer (FGFR1 or FGFR2) — broad, deviated thumbs and great toes; Muenke (FGFR3) — coronal with hearing loss; Saethre-Chotzen (TWIST1) — ptosis and small ears. The recurring question: posterior plagiocephaly. Positional — a parallelogram-shaped head, the ear on the same side moves forward and the forehead on the same side bulges; lambdoid synostosis — a trapezoid head, the ear on the same side moves backward and downward and a bulge behind the ear. Positional plagiocephaly is far commoner and is treated by repositioning, "tummy time" and physiotherapy for torticollis, with a helmet reserved for moderate to severe cases.
Key points
- Sagittal — the commonest, long narrow head.
- Unicoronal — harlequin orbit.
- Apert — syndactyly; Crouzon — no hand anomaly.
- Positional — parallelogram and ear forward; lambdoid — trapezoid and ear backward.
- Endoscopic up to 3 to 4 months; open at 6 to 12.
Summary table
| Suture | Head shape | Distinguishing sign | Treatment |
|---|---|---|---|
| Sagittal | Scaphocephaly — long and narrow | The commonest | Endoscopic up to 3 to 4 months, or open at 6 to 12 |
| Metopic | Trigonocephaly — triangular forehead | Forehead ridge, close-set eyes | Anterior remodelling when severe |
| Unicoronal | Anterior plagiocephaly | Harlequin orbit, nose deviates to the affected side | Fronto-orbital remodelling |
| Bicoronal | Brachycephaly | Usually syndromic (FGFR) | Craniofacial team |
| Lambdoid versus positional | Trapezoid versus parallelogram | Ear backward versus ear forward | Surgery versus repositioning and helmet |
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Sources
- Congress of Neurological Surgeons guideline on the management of positional plagiocephaly, 2016 — Repositioning, physical therapy and helmets
- European guideline on craniosynostosis (ERN CRANIO), 2020 — Diagnosis, surgery timing and syndromic care
- Youmans and Winn Neurological Surgery, 8th edition (2022) — Craniosynostosis
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-06. The text may contain errors; when in doubt, check the source.