Posterior Cricoarytenoid Bellies: Relationship Between Their Function and Histology

Dynamics of Intrinsic Laryngeal Muscle Contraction

“…8 The slight difference in fiber composition is consistent with the sphincter function of the vertical belly in phonation and swallowing, which requires a relatively short response time; and the more dominant role in respiration of the horizontal belly, which is active during inspiration. 8 During in vivo neuromuscular stimulation of a canine larynx, the PCA has a slow time course of activation, with changes first appreciable by 16 to 33 ms and maximum posture change achieved by 100 ms. 5 The cricothyroid (CT) muscle is composed of two bellies, the pars recta and pars oblique. Together these two components pull the anterior part of the cricoid cartilage backward and upward to lengthen vocal fold, constrict the glottis, and dilate the pharynx.…”

“…Previous investigations of ILM function have primarily focused on ILM role in voice production and in the control of laryngeal posture, but the dynamics of ILM movement has received little attention. Laryngeal muscle dynamics reflect the muscle fiber composition, which is reported as a percentage of type 1 (slow) and type 2 (fast) fibers (Table ) …”

“…Laryngeal muscle dynamics reflect the muscle fiber composition, which is reported as a percentage of type 1 (slow) and type 2 (fast) fibers (Table I). 6,8,[22][23][24][25][26][27][28][29][30] Laryngeal adductor muscles include the paired thyroarytenoid (TA) and lateral cricoarytenoid (LCA) and the unpaired interarytenoid (IA). The TA moves the vocal process medially and inferiorly during vocal fold adduction.…”

Nerve branches to the posterior cricoarytenoid muscle may complicate the laryngeal reinnervation procedure

“…One clinically significant point in understanding the neuromuscular compartments of the PCA muscle and its functions relates to the reinnervation of the paralyzed PCA muscle. The division of the PCA muscle into horizontal and vertical/oblique compartments in humans and dogs is well documented and is based on a large body of evidence, including histochemical and functional evidence . The vertical/oblique compartment may be involved primarily in vocal cord abduction during inspiration .…”

Laryngeal Muscles

“…The posterior cricoarytenoid muscle has been reported as comprising two bellies: horizontal or medial and vertical or lateral (Poirier and Charpy 1903;Bryant et al 1996;Asanau et al 2011). However, it has recently been considered as comprising three constant bellies or compartments: horizontal, vertical, and oblique (Sanders et al 1994).…”