Fiber arrangements of the vertical lingual muscle in human adult subjects

This study identified the anatomy of the vertical lingual muscle and functional relationships between the vertical lingual and the other lingual muscles in the human tongue. Three whole tongues were obtained from adult human cadavers and were used for histological study by the serial section method. At the tip of the tongue, the fibers of the vertical lingual muscle cross with the transverse lingual muscle, and extend inferiorly to the fibers of the inferior longitudinal lingual muscle. At the body of the tongue, the fibers of the vertical lingual muscle are located between the fibers of the superior longitudinal lingual and inferior longitudinal lingual muscle, crossing the fibers of the transverse lingual muscle, instead of crossing the fibers of the extrinsic lingual muscles. At the base of the tongue, the fibers of the vertical lingual muscle start by the fibers of the superior longitudinal lingual muscle, and connect with the fibers of the posterior muscle bundle of the styloglossus muscle. The average diameters of the vertical lingual muscle fibers increased gradually as they approached the base of the tongue. These findings suggest that posterosuperior movement of the tongue body may be accomplished with downward movement of the tip of the tongue by contractions of both the vertical lingual and the styloglossus muscle. The inferior longitudinal lingual muscle may also play a supporting role for the vertical lingual muscle at the tip of the tongue (AU)

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A case of Creutzfeldt-Jacob disease with bilateral vocal fold abductor paralysis.

Bilateral vocal fold abductor paralysis was seen in a patient with Creutzfeldt-Jacob disease. After tracheotomy, the patient showed disappearance of reduced oxygen saturation with high-pitched inspiratory stridor and pulling phenomenon of the supraclavicular region and larynx. Electromyographic examinations of the intrinsic laryngeal muscles, including the thyroarytenoid and posterior cricoarytenoid muscles, demonstrated that there was no apparent action potential in those muscles during spontaneous respiratory movements, and there was no abnormal potential for those muscles at rest. By pushing the infrasternal region of the patient on the expiration, normal motor unit action potential could be seen in the posterior cricoarytenoid muscle on the next inspiration. Based on those findings, we concluded that bilateral vocal fold abductor paralysis in this case of Creutzfeldt-Jacob disease was not induced by disorders of the degeneration of motor nucleus in the ambiguus as in multiple system atrophy, but by a disorder of the upper motor neuron.

[Progressive dysphagia with peculiar laryngeal movement induced by tardive dystonia].

Recently, patients receiving the long-term administration of typical antipsychotics have been recognized to be at risk of developing intractable tardive dystonia. A 44-year-old man was referred to our hospital because of progressive dysphagia for about 5 years. He had received several typical antipsychotic medications since at age of 24 years for the treatment of chronic schizophrenia. The patient had been suffering from an abnormal sensation in his throat and progressive dysphagia for five years, and nasal escape on deglutition for one year. A videotape recorder esophago pharyngography revealed that his larynx was positioned low, at the level of the 6th cervical vertebra, before swallowing, and was not elevated but rather descended to the level of the 7th vertebra upon swallowing. When the larynx was in this lower position, a small amount of swallowed material was transported to the esophagus. The remaining material in the pyriform sinus overflowed into the laryngeal cavity and lower airway after swallowing. However, the patient was able to eat with ease when he was with a girl friend, eating in a restaurant, and was hungry. The peculiar downward movement of the larynx was not observed during speech production, only during deglutition. Based on these findings, we suspected that his peculiar swallowing disorder might have been induced by tardive dystonia arising from the long-term administration of typical antipsychotics.

M-mode color Doppler ultrasonic imaging of vertical tongue movement during articulatory movement.

To observe and estimate the movement of the tongue, ultrasonic investigation is the most harmless real-time monitoring procedure for analyzing articulatory movements. Color Doppler ultrasonic imaging is special in that it can only sample a moving target, and it can indicate the velocity and direction of the target by color and brightness in real time. This study assessed and demonstrated the validity of M-mode color Doppler ultrasonic imaging to observe the movements of the tongue during syllable repetition tasks performed by normal subjects and dysarthric patients, those affected by amyotrophic lateral sclerosis, cerebellar ataxia, Parkinsonism, and polymyopathy. When the transducer was set below the jaw, upward movement was indicated by a blue signal and downward movement was indicated by a red one on the screen of the ultrasound machine. We also measured the velocity of the tongue by contrast scale classified by 15 degrees. Thus, we could observe vertical tongue movement by a color-coded pattern after quantitative analysis. The Doppler signal patterns of normal subjects were verified by simultaneous video x-ray fluorography recordings. The findings for dysarthric patients corresponded well with previously reported features analyzed by other methods. Therefore, color Doppler ultrasonic imaging of the tongue is a useful procedure to researchers for clinical speech and voice studies.

Physiological studies of retrusive movements of the human tongue.

SUMMARY: This study identified that physiologically the superior pharyngeal constrictor muscle at the level of the base of the tongue contributes to retrusive movement of the tongue with constriction of the mid-pharyngeal cavity and possesses unique properties in terms of motor speech control along with the genioglossus muscle. From a kinematic study involving trans-nasal fiberscopy and lateral X-ray fluorography, retrusive movement of the tongue was highly correlated with constrictive movement of the mid-pharyngeal cavity. An electromyographic study revealed that the superior pharyngeal constrictor muscle at the level of the base of the tongue contributes to retrusive movement of the tongue and that the genioglossus muscle contributes to protrusive movement. We also noted that this relationship between the activities of these two muscles were in response to postural changes during vowel productions without changes in the acoustic features. These findings suggest that these two muscles act not only antagonistically to produce retrusive and protrusive movement of the tongue, but also they complement each other to conserve the shape of the vocal tract for speech production. The functional relationship between these two muscles could contribute the consecutive movement of human speech production under various conditions and might be useful when applying rehabilitation approaches for the patients with neurological speech and swallowing disorders.