title: Human Foramen Magnum Area and Posterior Cranial Fossa Volume Growth in Relation to Cranial Base Synchondrosis Closure in the Course of Child Development.
abstract: BACKGROUND
  To date, no study has compared the evolution of the foramen magnum area (FMA) and the posterior cranial fossa volume (PCFV) with the degree of cranial base synchondrosis ossification.
  
  
  OBJECTIVE
  To illustrate these features in healthy children.
  
  
  METHODS
  The FMA, the PCFV, and the ossification of 12 synchondroses according to the Madeline and Elster scale were retrospectively analyzed in 235 healthy children using millimeter slices on a computed tomography scan.
  
  
  RESULTS
  The mean FMA of 6.49 cm in girls was significantly inferior to the FMA of 7.67 cm in boys (P < .001). In both sexes, the growth evolved in a 2-phase process, with a phase of rapid growth from birth to 3.75 years old (yo) followed by a phase of stabilization. In girls, the first phase was shorter (ending at 2.6 yo) than in boys (ending at 4.33 yo) and proceeded at a higher rate. PCFV was smaller in girls (P < .001) and displayed a biphasic pattern in the whole population, with a phase of rapid growth from birth to 3.58 yo followed by a phase of slow growth until 16 yo. In girls, the first phase was more active and shorter (ending at 2.67 yo) than in boys (ending at 4.5 yo). The posterior interoccipital synchondroses close first, followed by the anterior interoccipital and occipitomastoidal synchondroses, the lambdoid sutures simultaneously, then the petro-occipital and spheno-occipital synchondroses simultaneously.
  
  
  CONCLUSIONS
  The data provide a chronology of synchondrosis closure. We showed that FMA and PCFV are constitutionally smaller in girls at birth (P ≤ .02) and suggest that a sex-related difference in the FMA is related to earlier closure of anterior interoccipital synchondroses in girls (P = .01).
  
  
  BACKGROUND
  AIOS, anterior interoccipital synchondrosesFMA, foramen magnum areaLS, lambdoid suturesOMS, occipitomastoidal synchondrosesPCFV, posterior cranial fossa volumePIOS, posterior interoccipital synchondrosesPOS, petro-occipital synchondrosesSOS, spheno-occipital synchondrosisyo, years old.
authors.affiliation: *Service de Neurochirurgie, Hôpital Gabriel Montpied, Clermont-Ferrand, France;‡Laboratoire d'anatomie, Université Clermont Auvergne, Université d'Auvergne, Clermont-Ferrand, France;§Université Clermont Auvergne, Université d'Auvergne, EA 7282, Image Guided Clinical Neurosciences and Connectomics, Clermont-Ferrand, France;¶Unité de Chirurgie Craniofaciale, Service de Neurochirurgie Pédiatrique, Centre de Référence National des Dysostoses Crâniofaciales, Hôpital Necker-Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France;‖Service de Chirurgie Maxillo-Faciale, Hôpital Estaing, Clermont-Ferrand, France;#Service de Radiologie Pédiatrique, Hôpital Estaing, Clermont-Ferrand, France.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Coll
authors.forename: Jean-Jacques
authors.initials: JJ
authors.lastname: Lemaire
authors.forename: Federico
authors.initials: F
authors.lastname: Di Rocco
authors.forename: Isabelle
authors.initials: I
authors.lastname: Barthélémy
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Garcier
authors.forename: Emmanuel
authors.initials: E
authors.lastname: De Schlichting
authors.forename: Laurent
authors.initials: L
authors.lastname: Sakka
mesh_terms: D000293:Adolescent; D002648:Child; D002657:Child Development; D002675:Child, Preschool; D003388:Cranial Fossa, Posterior / Q000000981:diagnostic imaging / Q000254:growth & development*; D003393:Cranial Sutures / Q000000981:diagnostic imaging / Q000254:growth & development*; D005260:Female; D005539:Foramen Magnum / Q000000981:diagnostic imaging / Q000254:growth & development*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D010012:Osteogenesis; D012189:Retrospective Studies; D012727:Sex Characteristics; D019291:Skull Base / Q000000981:diagnostic imaging / Q000254:growth & development*; D014057:Tomography, X-Ray Computed