title: Real-time monitoring of the growth of the nasal septal cartilage and the nasofrontal suture.
abstract: BACKGROUND
  The nasal septum is thought to be a primary growth cartilage for the midface and, as such, has been implicated in syndromes involving midfacial hypoplasia. However, this internal structure is difficult to study directly. The aims of this study were to provide direct, continuous measurements of the growth of the nasal septal cartilage and to compare these with similar measurements of the nasofrontal suture to test whether the growth of the cartilage precedes the growth of the suture and whether the growth of the septal cartilage is constant or episodic.
  
  
  METHODS
  Ten Hanford minipigs were used. Linear displacement transducers were implanted surgically in the septal cartilage and across the nasofrontal suture. Length measurements of the cartilage and suture were recorded telemetrically each minute for several days.
  
  
  RESULTS
  The growth rate of the nasal septal cartilage (0.07% ± 0.03% length/h) was significantly higher than that of the suture (0.03% ± 0.02% length/h) (P = 0.004). The growth of both structures was episodic with alternating periods of growth (5-6 per day) and periods of stasis or shrinkage. No diurnal variation in growth of the cartilage was detected.
  
  
  CONCLUSIONS
  These results are consistent with the notion that growth of the septal cartilage might drive growth of the nasofrontal suture. Growth of the midface is episodic rather than constant.
authors.affiliation: Department of Orthodontics, School of Dentistry, University of Washington, Seattle, WA 98195, USA. drayman@uw.edu
authors.forename: Ayman A
authors.initials: AA
authors.lastname: Al Dayeh
authors.forename: Katherine L
authors.initials: KL
authors.lastname: Rafferty
authors.forename: Mark
authors.initials: M
authors.lastname: Egbert
authors.forename: Susan W
authors.initials: SW
authors.lastname: Herring
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D002508:Cephalometry / Q000295:instrumentation; D002940:Circadian Rhythm / Q000502:physiology; D003393:Cranial Sutures / Q000254:growth & development*; D005260:Female; D005624:Frontal Bone / Q000254:growth & development*; D008991:Monitoring, Physiologic / Q000295:instrumentation; D009295:Nasal Bone / Q000254:growth & development*; D055171:Nasal Cartilages / Q000254:growth & development*; D009300:Nasal Septum / Q000254:growth & development*; D013552:Swine; D013556:Swine, Miniature; D013686:Telemetry / Q000295:instrumentation; D013997:Time Factors; D014159:Transducers