(A) FTP I allows visualization of the entire uvula and tonsils/pillars. (B) FTP IIa allows visualization of most of the uvula, but the tonsils/pillars are absent. (C) FTP IIb allows visualization of the entire soft plate to the base of the uvula. (D) In FTP III some of the soft palate is visualized but the distal structures are absent. (E) FTP IV allows visualization of the hard palate only. Note that tongue should be relaxed within the mouth, not protruded.
Reproduced from: Friedman M. Friedman tongue position and the staging of obstructive sleep apnea/hypopnea syndrome. In: Sleep Apnea and Snoring: Surgical and Nonsurgical Therapy, Scheidt S, Clansey N (Eds), Philadelphia, Elsevier 2009. Illustration used with the permission of Elsevier Inc. All rights reserved.
