Phonatory gap (1 of 4)
At the prephonatory instant, D4 (~294 Hz), standard light. Notice how separated the vocal cords are.

Phonatory gap (2 of 4)
Phonation, a moment later, with vibratory blur. The cords remain separated. The question is whether this gap is due to: 1) a posturing problem, such as muscular tension dysphonia (MTD); 2) flaccidity-induced bowing; 3) some other cause.

Phonatory gap (3 of 4)
The most “closed” phase of vibration, as seen under strobe light, at the relatively low pitch of F4 (~349 Hz); again, the cords are not actually closed. This is not the picture of MTD, however; with MTD, there would be a greater gap between the vocal processes of the arytenoid cartilages (at arrows).

Phonatory gap (4 of 4)
Open phase of vibration, at the same pitch as photo 3. The lateral amplitude of each cord's vibration is equal, and relatively small (midline shown by a dotted line), which would not be seen with vocal cord flaccidity. Hence, neither MTD nor flaccidity is the explanation for this patient's gap. Also, this patient's voice manifests "popping" onset delays that are similar to other phonatory gap patients who have neither MTD nor flaccidity.