title: Computed tomographic study of the effect of a tongue-tie on hyoid apparatus position and nasopharyngeal dimensions in anesthetized horses.
abstract: OBJECTIVE
  To determine the effect of manual tongue protrusion on the dimensions of the hyoid apparatus, nasopharynx, and oropharynx in anesthetized horses. tongue protrusion on the dimensions of the hyoid.
  
  
  METHODS
  5 adult horses.
  
  
  METHODS
  Horses were anesthetized and positioned in sternal recumbency for 2 sequential computed tomographic (CT) scans. Images were acquired with the tongue in a natural position inside the mouth. Then, the tongue was pulled rostrally and secured, and a second CT scan was performed. Dorsoventral length of the hyoid apparatus and angles of the basisphenoid, basihyoid, and ceratohyoid were measured on 3-dimensional reconstructed CT images. Cross-sectional diameters and areas of the nasopharynx and oropharynx were determined on reformatted images in the transverse and longitudinal planes, using osseous landmarks for consistency. Results were tested between the 2 groups to determine significant differences.
  
  
  RESULTS
  We were unable to detect a significant difference between any of the lengths or angles of the hyoid apparatus measured with or without rostral protrusion of the tongue. Similarly, nasopharyngeal and oropharyngeal diameters and cross-sectional areas were not significantly different with or without rostral protrusion of the tongue.
  
  
  CONCLUSIONS
  Tying the tongue rostrally out of a horse's mouth did not influence the position of the hyoid apparatus or dimensions of the nasopharynx or oropharynx in anesthetized horses. Currently, no data suggest that application of a tongue-tie is effective for maintaining stability and patency of the nasopharyngeal or orolaryngeal airways in horses during races.
authors.affiliation: Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing 48624, USA.
authors.forename: C J
authors.initials: CJ
authors.lastname: Cornelisse
authors.forename: D S
authors.initials: DS
authors.lastname: Rosenstein
authors.forename: F J
authors.initials: FJ
authors.lastname: Derksen
authors.forename: S J
authors.initials: SJ
authors.lastname: Holcombe
mesh_terms: D000758:Anesthesia / Q000662:veterinary; D000818:Animals; D006736:Horses / Q000033:anatomy & histology / Q000502:physiology*; D006928:Hyoid Bone / Q000033:anatomy & histology / Q000502:physiology*; D009305:Nasopharynx / Q000033:anatomy & histology / Q000502:physiology*; D012149:Restraint, Physical / Q000662:veterinary*; D018709:Statistics, Nonparametric; D014057:Tomography, X-Ray Computed / Q000662:veterinary; D014059:Tongue / Q000033:anatomy & histology / Q000502:physiology*