After the surgical treatment for early glottic carcinoma, the patients end up with voice disturbances in different grades. The aim of this study was to characterize the laryngeal configuration regarding the anterior commissure synechia and its relationship to the perceptual vocal quality. Twenty-five patients underwent frontolateral vertical partial laryngectomy and reconstruction with bipedicle sternohyoid muscle flap resulting from T1b/T2 glottic squamous cell carcinoma from January 1996 to December 2004. Of the 25 patients, 24 were male with a median age of 61 years. The patients were free of disease and the evaluation was performed after a minimum postoperative period of 12 months. Measurements of the anterior commissure synechia and the free border of both vocal folds were simultaneously performed with the perceptual analysis of the voice through GRBAS scale. We calculated the mathematical proportion between the midsagittal dimension of the synechia of the anterior commissure and the measurement of the free border of the intermembranous region of each vocal fold. The higher the relative measurement of the anterior commissure synechia, the worse the overall grade of hoarseness (G) for both vocal folds (P<0.001), the worse the roughness (R) for both vocal folds (P<0.001), and the worse the strained quality (S) for both the reconstructed (P=0.0086) and the preserved (P=0.0026) vocal folds. These results suggest that the relative measurement of the anterior commissure synechia is a crucial factor worsening voice quality and that the perceptual analyses score has a strong correlation to the synechia's impact.