Figure 1 - Order of events in swallowing.

Timeline of order of events in swallowing as compiled from needle electromyography (EMG), endoscopy, fluoroscopy, and submental EMG. Whiteout^*: time period the videoendoscopic image is obscured owing to pharyngeal closure. Genioglossal^*: EMG activity in the genioglossal muscle using intramuscular hooked wire electrodes. Mylohyoid^*: EMG activity in the mylohyoid muscle using intramuscular hooked wire electrodes. Geniohyoid^*: EMG activity in the geniohyoid muscle using intramuscular hooked wire electrodes. Submental^**: EMG activity from submental surface electrodes. Hyoid ascent^***: Elevation of the hyoid from ultrasound images. Hyoid descent^***: Descent of the hyoid from ultrasound images. Epiglottic movement^***: Time period the epiglottis begins inversion, remains inverted, and returns to normal position as seen via videoendoscopy. Superior constrictor^*,**: EMG activity in the superior constrictor muscle using intramuscular hooked wire electrodes. Longitudinal pharyngeal musculature^*: EMG activity in the posterior faucial pillars using intramuscular hooked wire electrodes. Cricopharyngeal relaxation^*,**: Decrease in EMG activity in the cricopharyngeus muscle using intramuscular hooked wire electrodes. Arytenoids medializing^*: Time period representing the movement of the arytenoids toward the midline as seen via videoendoscopy. Arytenoids medialized^*: Time period the arytenoids remain in the midline during a swallow as seen with a combination of videoendoscopy and fluoroscopy. Arytenoids tilted/vestibular closure^****: Time period the arytenoids begin movement toward the base of the epiglottis and remain there resulting in vestibular closure as seen via fluoroscopy. Thyroarytenoid^*,**: EMG activity in the thyroarytenoid muscle using intramuscular hooked wire electrodes. Interarytenoid^**: EMG activity in the interarytenoid muscle using intramuscular hooked wire electrodes. Key: ^*McCulloch et al., unpublished data; ^**Perlman AL, Palmer PM, McCulloch TM, Van Daele DJ. Electromyographic activity from human laryngeal, pharyngeal and submental muscles during swallowing. J Appl Physiol 1999;86(5):1663 –1669. ^***Perlman AL, Van Daele DJ. Simultaneous videoendoscopic and ultrasound measures of swallowing. J Med Speech Lang Pathol 1993;1(4):223 –232. ^****Shaker R, Dodds WJ, Dantas RO, Hogan WJ, Arndorfer RC. Coordination of deglutitive glottic closure with oropharyngeal swallowing. Gastroenterology 1990;98:1478–1484. Note: Dashed and thin lines represent standard deviations. (Source: Langmore⁵³ with permission from Thieme New York)