title: Growth and development of the cranial base in mice that spontaneously develop anterior transverse crossbite.
abstract: BACKGROUND
  Homozygous brachymorphic (bm/bm) mice are characterized by disproportionately short stature. Anterior transverse crossbite sometimes develops spontaneously in inbred BALB/c-bm/bm mice that produce undersulfated glycosaminoglycans. The reason for inferior growth of the craniofacial structures of BALB/c-bm/bm mice has not been clarified. We focused on the spheno-occipital synchondrosis (SOS)-the growth site of the cranium-and investigated the growth pattern in the SOS of the BALB/c-bm/bm mice.
  
  
  METHODS
  The BALB/c-+/+ mice and BALB/c-bm/bm mice without malocclusion were used. Sagittal sections of the cranial bases were stained with hematoxylin and eosin, observed histologically, and used to measure the anteroposterior length and the percentage of active bone volume around the SOS.
  
  
  RESULTS
  In the histologic study, compared with the cartilage in the BALB/c mice, a bipolar column was not seen in the cartilage of the SOS in the BALB/c-bm/bm mice. The histomorphometric study showed that the anteroposterior length of the posterior cranial base was significantly shorter and the percentage of active bone volume was significantly smaller in the BALB/c-bm/bm mice than in the BALB/c mice.
  
  
  CONCLUSIONS
  The results suggested that normal endochondral growth is disturbed in the synchondrosis of the posterior base of the skull in BALB/c-bm/bm mice.
authors.affiliation: Graduate student, Department of Orthodontics, Division of Oral Functional Science, Graduate School of Dental Medicine, Hokkaido University, Sapporo, Japan. tsukako@den.hokudai.ac.jp
authors.forename: Yuri
authors.initials: Y
authors.lastname: Tsukamoto
authors.forename: Takashi S
authors.initials: TS
authors.lastname: Kajii
authors.forename: Yasutomo
authors.initials: Y
authors.lastname: Oonishi
authors.forename: Yuki
authors.initials: Y
authors.lastname: Sugawara-Kato
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Hirabayashi
authors.forename: Junichiro
authors.initials: J
authors.lastname: Iida
mesh_terms: D000818:Animals; D002356:Cartilage / Q000254:growth & development* / Q000503:physiopathology; D002508:Cephalometry; D019465:Craniofacial Abnormalities / Q000150:complications* / Q000503:physiopathology; D004195:Disease Models, Animal; D005260:Female; D008310:Malocclusion / Q000150:complications / Q000503:physiopathology*; D008445:Maxillofacial Development; D051379:Mice; D008807:Mice, Inbred BALB C; D008817:Mice, Mutant Strains; D009777:Occipital Bone / Q000254:growth & development* / Q000503:physiopathology; D019291:Skull Base; D013100:Sphenoid Bone / Q000254:growth & development* / Q000473:pathology; D018709:Statistics, Nonparametric