Pattern of Gross Displacement of the Vocal Fold in Adduction and Abduction Movements

Abstract

The pattern of gross displacement of the vocal fold during adduction and abduction was studied in 4 adult fresh human larynges (2 males and 2 females). Markers were placed on specific sites along the edge of the vocal fold. Preliminary observations showed upward and lateral movement of the free edge during abduction. The vocal fold as a whole glides into and fills the cavity of the laryngeal ventricle. To quantify this observation 14 larynges (8 males and 6 females) were studied, using a technique designed to measure vertical and horizontal displacement of the vocal fold. An average of a 1.34 mm elevation and 4.43 mm lateral excursion were observed at midvocal fold level. A model for studying the pattern of vocal fold abduction is suggested and discussed.

A three-dimensional model of vocal fold abduction/adduction

“…Previous studies of vocal posturing mechanics focused on quantifying the range and direction of arytenoid cartilage motion around the cricoarytenoid joint (CAJ) (Broad, 1968;Kotby et al, 1992). Although such descriptive kinematics provided a logical foundation for understanding CAJ-based posturing, a study of the forces caused by laryngeal connective tissues is needed to establish causal relations between vocal posturing and laryngeal muscle forces.…”

Review of range of arytenoid cartilage motion

“…Kotby et al 4 studied the gross displacement of the vocal-fold edge during abductory/adductory motion (simulated by placing tension on sutures attached to the arytenoid). Using 14 fresh adult human larynges (eight male, six female), the displacement in the coronal plane (left-right and up-down) was tracked at three points along the vocal-fold length (middle, 4-mm anterior, and 4-mm posterior); Kotby's posterior point was assumed from the description (though not directly a)…”

“…Five papers [2][3][4][5][6] reporting measures of ranges from laboratory experiments were found to discuss arytenoid motion using a landmark that was equivalent to the vocal process. For several of these studies, it was necessary to calculate arytenoid cartilage motion from the data given in terms of the vocal process (the true anatomical vocal process at the tip of the arytenoid, VP T ; or the medial vocal-fold edge near the vocal process, VP M ).…”