Weakness or paralysis of the vocal cord’s thyroarytenoid (TA) muscle, but with normal function of the vocal cord’s other muscles. The TA muscle “inhabits” the vocal cord and normally provides bulk and internal tone to the cord. The following are indicators of TA-only paresis:
- Movement: The vocal cord opens normally for breathing and closes normally for voicing.
- Position and appearance: Position is normal. Typically, the margin of the cord is slightly concave, the ventricle is capacious, and the conus area below the free margin is lacking in bulk.
- Appearance during voicing (under strobe lighting): Closure at the posterior commissure is complete and symmetrical bilaterally. Under strobe light, one sees flaccidity as indicated by increased amplitude of vibration; the lateral excursions become exaggerated and the mucosal wave increases. One may also see chaotic fluttering.
- Voice quality: Weak and air-wasting and often indistinguishable from a case of complete vocal cord paralysis—TA, LCA (lateral cricoarytenoid), and PCA (posterior cricoarytenoid).
Photos of TA-only paresis:
Paresis, TA-only: before and after an Implant
TA-only Paresis before and after Voice Gel Injection
Just Bowing? No, TA-only Paresis
TA-only Paresis, before and after Recovery
Another TA-only Paresis
Arytenoid Mismatch Makes for Gravelly Voice Quality Is Hard to Fix in Some Cases of Vocal Cord Paralysis
One could medialize more aggressively posteriorly on the left, hoping to raise the level of the cord, but often attempts to compensate for arytenoid mismatch such as that seen here are only modestly successful. Arytenoid superstructure is not useful for assessment of match; instead, the examiner should judge match at the vocal processes.