C_S_D 4220 Lecture Notes - Lecture 2: Aphonia, Harmonic Analysis, Formant
31 May 2016
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Layers: contributes to glottal wave/cycle: 1. Distributes mucus on vf edge: 2. Primary vibrating structure of vf: 3. Potential to vibrate; abnormal: thyrohyoid membrane. Connective tissue between thyroid cartilage and hyoid bone: quadrangular membrane. Connects aryepiglottic and ventricular folds: conus elasticus. Broad elastic membrane; covers inner wall of larynx. Vagus (cn 10): 3 branches: 1. Lateral cricothyroid, thyroarytenoid, & interarytenoid m. Innervates posterior cricoarytenoid m: 3. Sensory and autonomic fibers to laryngeal mucousa. Phonation is the result of the interaction between muscular (including elasticity) and aerodynamic forces [helmholtz & muller (1800"s), van den berg (19558): myoelastic forces. Longitudinal tension- stiffens vf; increases resistance to subglottal pressure (ps) Vf layers- mechanical coupling pulls vf as a unit. Vf mass- greater mass of vocalis m. -> greater resistance to ps: aerodynamics. Upper portion of vf moves apart due to mechanical coupling. When mechanical resistance (myoelastic forces) exceeds intraglottal pressure- vf begin to close.
