B-mode real-time ultrasound assessment of vocal cord function in recurrent laryngeal nerve palsy.

B-mode real-time ultrasound was used to assess vocal cord function in six patients with recurrent laryngeal nerve palsy. The thyroid cartilage acted as an acoustic window through which the true cords appear as hypoechoic structures. Vocal cord palsy detected on ultrasound was compared with fibreoptic direct laryngoscopy and indirect laryngoscopy mirror examination. Good correlation was seen in all the cases.