Ultrasound morphometry of the cervical vagus nerve for daily clinical practice: Reference values for cross sectional area and fascicle count

•Sonographic reference values for Cervical Vagus Nerve size in normal volunteers are provided.•The Cervical Vagus Nerve is usually mono- or oligo-fascicular with a honeycomb appearance.•The right Cervical Vagus Nerve has larger cross-sectional area and contains more fascicles than the left.•The Cervical Vagus Nerve cross-sectional area is associated to BMI but not to age and sex.