title: Ultrasound of the Hypoglossal Nerve in the Neck: Visualization and Initial Clinical Experience with Patients.
abstract: OBJECTIVE
  The hypoglossal nerve, providing motor innervation for the tongue, can be affected in many diseases of the neck and skull base, leading to dysarthria, dysphagia, and ultimately atrophy of the tongue. We determined the feasibility of direct visualization of the hypoglossal nerve in the neck with ultrasound, testing this technique on healthy volunteers and evaluating it in clinical practice.
  
  
  METHODS
  The study consisted of 4 parts: first, ultrasound-guided perineural ink injections along the course of the hypoglossal nerve at 24 sides of 12 fresh, nonembalmed cadaver necks. Subsequently, the specimens were dissected to confirm the correct identification of the nerve. The second part was examination of healthy volunteers with ultrasound and measurement of cross-sectional areas for generating reference data. The third part was scanning of healthy volunteers by 2 resident physicians with little and intermediate experience in ultrasound. Fourth was examination with ultrasound of patients with motor symptoms of the tongue.
  
  
  RESULTS
  The hypoglossal nerve was correctly identified bilaterally in all cadaveric specimens (24/24) and all volunteers (33/33). The cross-sectional area ranged from 1.9 to 2.1 mm(2). The resident physicians were able to locate the nerve in 19 of 22 cases, demonstrating that locating the nerve is reproducible and feasible even with intermediate experience in ultrasound. Finally, alterations of the hypoglossal nerve in disease states could be depicted.
  
  
  CONCLUSIONS
  Direct, reliable, and reproducible visualization of the extracranial hypoglossal nerve with ultrasound is feasible.
authors.affiliation: From the Departments of Radiology (S.M.) Center for Anatomy and Cell Biology (S.M., L.F.R., W.W.) stefan.meng@meduniwien.ac.at.
authors.forename: S
authors.identifier: http://orcid.org/0000-0002-1606-9817
authors.initials: S
authors.lastname: Meng
authors.affiliation: Center for Anatomy and Cell Biology (S.M., L.F.R., W.W.).
authors.forename: L F
authors.identifier: http://orcid.org/0000-0001-5833-8176
authors.initials: LF
authors.lastname: Reissig
authors.affiliation: Division of Plastic and Reconstructive Surgery (C.-H.T.), Department of Surgery, Medical University of Vienna, Vienna, Austria.
authors.forename: C-H
authors.identifier: http://orcid.org/0000-0002-3903-801X
authors.initials: CH
authors.lastname: Tzou
authors.affiliation: Ear, Nose, and Throat Diseases (K.M.).
authors.forename: K
authors.identifier: http://orcid.org/0000-0001-9181-6803
authors.initials: K
authors.lastname: Meng
authors.affiliation: Neurology (W.G.), KFJ Hospital, Vienna, Austria.
authors.forename: W
authors.identifier: http://orcid.org/0000-0003-0593-1704
authors.initials: W
authors.lastname: Grisold
authors.affiliation: Center for Anatomy and Cell Biology (S.M., L.F.R., W.W.).
authors.forename: W
authors.identifier: http://orcid.org/0000-0003-0575-0073
authors.initials: W
authors.lastname: Weninger
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D007002:Hypoglossal Nerve / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D014463:Ultrasonography / Q000379:methods*