[Study on the relationship among the projective positions of interior laryngeal structure on thyroid ala].

Objective: To provide anatomic basis of locations of laryngeal interior structures for laryngeal operating through lateral laryngeal approaches in clinic.
Method: Thirty cadavers laryngeal cartilage specimens (19 male and 11 female) was collected. Using pin pierced method under direct vision to locate the projections of muscle process of arytenoids cartilage and vocal fold on thyroid ala, then to observe their relationships.
Result: The projection of vocal fold is the line that connecting a little bit superior of the middle point of anterior commissure of thyroid cartilage and the point on the crosspoint of superior 3/4 and inferior 1/4 of the posterior edge of thyroid cartilage ala. The angle of the line and anterior commissure of thyroid cartilage is sixty-five degrees. The projection of muscle process is locating on the projective line of vocal fold. The projection of pyriform fossa is locating at the posterior superior portion of thyroid cartilage ala.
Conclusion: The interior structures of larynx have a intact relationship of projective position on thyroid cartilage ala,which providing anatomic references for clinical surgeries relating to vocal fold through laryngeal framework.