Otolaryngology head and neck surgery: an integrative view of the larynx

Abstract

The glottis is composed of muscular, cartilaginous, and other viscoelastic tissues which perform some of our most important, complex, coordinated, and life-sustaining functions. Dominated by the thyroarytenoid muscles and associated glottic closure muscles, the larynx is involved in respiration, swallowing, voicing, coughing, valsalva, vomiting, laughing, and crying. With respiration continuing in the background, all other "secondary" laryngeal events seamlessly occur. When the delicate balance of coordinating these events is disrupted by disease or disorder, many of these tasks are compromised. Due to the complex innervation of these volitional and reflexive tasks with brainstem central pattern generators, primary sensorimotor areas and importantly, limbic areas, failure can occur due to disease, anatomic compromise, and even emotional state. Understanding the level of sensorimotor control and interaction among systems that share these laryngeal neuromuscular substrates will improve the diagnostic and therapeutic skill of the clinician when treating compromise of laryngeal function.

FIGURE 1

Basic anatomy of thyroarytenoid and associated laryngeal muscles.

FIGURE 2

(A) Thyroarytenoid (TA) activity with vocalization, Valsalva, and swallow (reproduced with permission from Laryngoscope 1996;106:1351–1358). (B) Activity profile from a subject with saliva and 10 mL water swallow. EMG, electromyography.

FIGURE 3

Timing of thyroarytenoid (TA) muscle activity (active glottic closure) relative to posterior cricoarytenoid (PCA) muscle Quiescence (reproduced with permission from Ann Otol Rhinol Laryngol 2005;114:478–487).

FIGURE 4

Electromyographic activity in deglutition for unanesthetized dog medulla. Height of line for each muscle indicated intensity of action observed (reproduced with permission from Neurophysiology 1956;19:44–60).

FIGURE 5

Timing of thyroarytenoid (TA) activity relative to bolus transport measured with simultaneous TA electromyography and fiber-optic examination of swallow with bolus transport recorded as video “whiteout”.