ABSTRACT
SUMMARY: As one of the suprahyoid muscles, the digastric muscle is characterized by two separate bellies of different embryologic origins. The origin of the anterior belly is the digastric fossa, while the origin of the posterior belly is the mastoid notch. They share a common insertion: the intermediate tendon. When the digastric muscle contracts, the hyoid bone is raised. Opening of the jaw and swallowing of food boli are associated with digastric muscle activity. This review discusses the general anatomic features of the digastric muscle and its variation, primary functions, and clinical implications focused on surgical reconstruction and rejuvenation.
Como uno de los músculos suprahioideos, el músculo digástrico se caracteriza por dos vientres separados, de diferentes orígenes embriológicos. El origen del vientre anterior es la fosa digástrica, mientras que el origen del vientre posterior es la incisura mastoidea. Comparten una inserción común, El tendón intermedio. Cuando el músculo digástrico se contrae, el hueso hioides se eleva. La apertura de la mandíbula y la deglución del bolo alimenticio se asocian con la actividad del músculo digástrico. Esta revisión analiza las características anatómicas generales del músculo digástrico y su variación, funciones primarias e implicaciones clínicas centradas en la reconstrucción y el rejuvenecimiento quirúrgico.
Subject(s)
Humans , Neck Muscles/anatomy & histology , Neck Muscles/physiologyABSTRACT
Suprahyoid muscles play an important role in normal swallowing by providing muscle contractions involved in airway protection and upper esophageal sphincter opening. However, these muscles can be weakened by neurological disease or aging, which can result in pharyngeal dysphagia. Therefore, strengthening of the suprahyoid muscles is a clinically important treatment. In addition, it is important to know exactly how and which method is optimal. Many therapeutic exercise methods have been reported to strengthen the suprahyoid muscles, and new methods related to this have recently been reported. Therefore, this study will briefly summarize the representative traditional methods and the recently reported, relatively new methods for strengthening the suprahyoid muscles.
Subject(s)
Aging , Deglutition , Deglutition Disorders , Esophageal Sphincter, Upper , Exercise , Methods , Muscle Contraction , Muscles , RehabilitationABSTRACT
Objective To explore the effect of theta-burst stimulation (TBS) of the motor cortex on the suprahyoid muscles and the mechanism through which the bilateral motor cortex regulates the suprahyoid muscles.Methods Continuous TBS (cTBS) was applied to the left motor cortex followed by intermittent TBS (iTBS) applied to the right motor cortex of 24 healthy subjects.The motor-evoked potentials (MEPs) of the suprahyoid muscles on both sides were recorded before the stimulation and after 15 and 30 minutes.The MEP amplitudes of the left and right suprahyoid muscles were analyzed using repeated measures analysis of variance.Results Before stimulation, the average MEP amplitudes of the left and right suprahyoid muscles were (375.29 ± 176.09) μV and (368.17 ± 149.02) μV respectively, significantly lower than the values after the stimulation.Conclusion iTBS can distinctly enhance the excitability of the right motor cortex controlling the suprahyoid muscles and reverse the inhibition caused by cTBS applied to the left motor cortex.Clarifying the effect of TBS on the excitability of the bilateral motor cortex is important for the rehabilitation of dysphagic stroke survivors.
ABSTRACT
OBJECTIVE To study the synchronous electromyograhic features of suprahyoid muscles [anterior digastric muscle(AD), posterior digastric muscle(PD),stylohyoid muscle(STH),mylohyoid muscle(MH)and geniohyoid muscle(GH)] and intrinsic laryngeal muscles [lateral cricoarytenoid muscle(LCA)and posterior cricoarytenoid muscle(PCA)]. METHODS Synchronous electromyograhic features of 13 dogs were observed under the circumstances of breath, swallowing and phonation. RESULTS ①AD, PD, STH, MH, GH and PCA discharged during inspiratory phase, while LCA discharged during expiratory phase. ②During swallow, suprahyoid muscles and LCA showed intensive synchronous discharge. The myoelectricity of PCA was suppressed while myopotential can be detected during intermission. ③During phonation, AD, PD, LCA and PCA showed an intensive synchronous discharge, while emergence time of PCA was later. GH and STH showed no myoelectricity activities. CONCLUSION①During phonation and swallowing, MH is synchronized with LCA. It can be chosen as the backup muscle for the reestablishment of glottic adduct function. ②During inspiratory phase, GH is synchronized with PCA. It can be chosen as the backup muscles for the reestablishment of vocal cord abduct function.