title: Effect of depressor septi nasi muscle activity on nasal lengthening with time.
abstract: BACKGROUND
  The depressor septi nasi (DSN) muscle is an important muscle in nose dynamics. Its hyperactivity causes smile deformity including nasal tip depression. The nasal tip of individuals with a hyperactive DSN muscle depresses repeatedly while they are speaking and smiling. This may result in nasal lengthening as they age.
  
  
  METHODS
  Pairs of cases consisting of a child and one of his or her parents were studied in two groups: case group (with DSN muscle hyperactivity) and the control group (with DSN muscle inactivity in both child and parent). Nasal length from nasion to tip and facial length from nasion to menton were measured during repose and during smiling.
  
  
  RESULTS
  This study investigated 80 pairs of children and parents. In both groups, a significant linear correlation between the nasal length of the parent and the child was found. In both groups (case and control), the nasal length of the child differed significantly from that of the parent. The increase in the nasal length of the parents compared with the children was greater in the control group.
  
  
  CONCLUSIONS
  This study demonstrated that nasal length increases with age and that DSN muscle hyperactivity is not an effective factor in this increase. This unpredictable result may affect the presumption that patients with DSN muscle hyperactivity will have longer noses in the future. Long-term prospective studies investigating cohort groups are required to clarify the variables affecting nasal lengthening with aging, and interventional studies are needed to examine the effects of DSN muscle resection on this phenomenon.
authors.affiliation: Surgical Oncology Research Center, Imam Reza Hospital, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran, beiraghia@mums.ac.ir.
authors.forename: Arash
authors.initials: A
authors.lastname: Beiraghi-Toosi
authors.forename: Ezzatollah
authors.initials: E
authors.lastname: Rezaei
authors.forename: Mehdi
authors.initials: M
authors.lastname: Jabbari Nooghabi
authors.forename: Shahram
authors.initials: S
authors.lastname: Izadpanah
mesh_terms: D000368:Aged; D000375:Aging / Q000502:physiology*; D005152:Facial Muscles / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009666:Nose / Q000033:anatomy & histology* / Q000502:physiology*; D013997:Time Factors