Which parameter describes the degree of horizontal excursion of the vocal folds?

• A. Amplitude of vibration
• B. Mucosal wave
• C. Phase closure
• D. Phase symmetry

Answer: (A)

The parameter that describes the degree of horizontal excursion of the vocal folds is the amplitude of vibration. This measures how far the folds move from their resting position in each vibratory cycle, i.e., the maximum lateral displacement as they open and close. A larger amplitude means the folds travel farther apart during each cycle, increasing the glottal opening and contributing to the overall sound intensity.

Other terms describe different aspects of vibration: the mucosal wave refers to the wave-like movement of the surface tissue across the folds, not the overall distance they travel; phase closure concerns how long the glottis remains closed within a cycle; and phase symmetry relates to whether the opening and closing phases are temporally balanced.