Geniohyoid Muscle: Anatomy and Clinical Implications in Dentistry / Músculo Geniohioideo: Anatomía e Implicaciones Clínicas en Odontología

SUMMARY: The geniohyoid muscle is one of the suprahyoid muslces, and arises from the inferior mental spine and inserts into the hyoid bone. The muscle is a narrow paired one and its main action is pulling the hyoid upward and forward. Its function is very important in deglutition as well as respiration. Therefore, this muscle has been extensively researched, especially in the context of dysphagia and sleep apnea. This review deals with the general anatomic features, main functions, and abnormal states of the geniohyoid muscle, and the clinical implications of these.

El músculo geniohioideo es uno de los músculos suprahioideos que surge de la espina mental inferior y se inserta en el hueso hioides. Son un par de músculo delgados y su acción principal es elevar y estirar el hueso hioides hacia arriba y hacia adelante. Su función es importante tanto en la deglución como en la respiración. Por lo tanto, este músculo ha sido ampliamente investigado, especialmente en el contexto de la disfagia y la apnea del sueño. Esta revisión trata de las características anatómicas generales, funciones principales y estados anormales del músculo geniohioideo, y las implicaciones clínicas de estos.

Ultrasound-guided electroacupuncture at suprahyoid muscle group for pharyngeal dysphagia after stroke: a randomized controlled trial / 中国针灸

OBJECTIVE@#To compare the effect among ultrasound-guided electroacupuncture (EA) at suprahyoid muscle group, conventional acupuncture and conventional EA at suprahyoid muscle group on pharyngeal dysphagia after stroke, and to explore its biomechanical mechanism.@*METHODS@#A total of 120 patients with pharyngeal dysphagia after stroke were randomly divided into an observation group, a control-1 group and a control-2 group, 40 cases in each group. The patients in the observation group were treated with ultrasound-guided EA at suprahyoid muscle group; the patients in the control-1 group were treated with EA at Lianquan (CV 23), Wangu (GB 12) and Fengchi (GB 20), etc.; the patients in the control-2 group were treated with EA at suprahyoid muscle group according to anatomical location. The EA in the three groups were discontinuous wave, with frequency of 5 Hz and current intensity of 1 mA. The EA was given for 30 minutes, once a day, 6 times were taken as a course of treatment, and 4 courses of treatment were provided. The video floroscopic swallowing study (VFSS) was performed before and after treatment. The Rosenbek penetration-aspiration scale (PAS) score, the forward and upward movement distance of hyoid bone and thyroid cartilage, Ichiro Fujima ingestion-swallowing function score were recorded in the three groups, and the incidences of subcutaneous hematoma were recorded after treatment.@*RESULTS@#Compared before treatment, the PAS scores were reduced and the Ichiro Fujima ingestion-swallowing function scores were increased after treatment in the three groups (P<0.05); the PAS scores in the observation group were lower than those in the control-1 group and the control-2 group, and the Ichiro Fujima ingestion-swallowing function scores in the observation group were higher than those in the control-1 group and the control-2 group (P<0.05). After treatment, the forward and upward movement distance of hyoid bone and thyroid cartilage in the observation group and the control-2 group was increased (P<0.05), and the forward and upward movement distance of hyoid bone was increased in the control-1 group (P<0.05); the forward and upward movement distance of hyoid bone and thyroid cartilage in the observation group was longer than that in the control-1 group and the control-2 group (P<0.05). The incidence of subcutaneous hematoma in the observation group was 0% (0/40), which was lower than 20.0% (8/40) in the control-1 group and 47.5% (19/40) in the control-2 group (P<0.05).@*CONCLUSION@#Ultrasound-guided EA at suprahyoid muscle group could improve the swallowing function in patients with pharyngeal dysphagia after stroke by increasing the motion of hyoid laryngeal complex. Its effect and safety are better than conventional acupuncture and conventional EA at suprahyoid muscle group.

Effects of viscosity and head position on the surface electromyography of the suprahyoid muscles during swallowing / 中华物理医学与康复杂志

Objective:To explore the effect of swallowing fluids of different viscosities in different head positions on the surface electromyography (sEMG) of the suprahyoid muscles.Methods:Twenty healthy adults were asked to swallow 5ml of liquids with 5 different viscosities in 3 different head positions. sEMG signals were recorded from their suprahyoid muscles in real time. The interactions between viscosity, head position and suprahyoid muscle activation were determined using simple effect analysis.Results:Significant head position and viscosity effects were observed. In the head-turning-right or the right head-flexion position, the net amplitude values of the left suprahyoid muscles were significantly higher than those from the right side when swallowing fluid of the same viscosity. Meanwhile, the net amplitude values of the left suprahyoid muscles increased gradually and significantly from the neutral position to the head-turning-right and the right head-flexion positions. When swallowing fluid with a viscosity of 0 to 3, the net amplitude values of the right suprahyoid muscles in the right head-flexion position were significantly lower than in the neutral and right head-flexion positions. With a viscosity of 4 the values of the former were significantly higher than the latter. The net amplitude of the left superhyoid muscle group when swallowing zero-viscosity food in a head-turning-right position was significantly lower than that when swallowing food of viscosity 1 to 4. In the right head-flexion position, the net amplitude of the left superhyoid muscle group when swallowing zero-viscosity food was significantly lower than that when swallowing food of viscosity 2 to 4. When swallowing fluid of viscosity 1 it was also significantly lower than that when swallowing food of viscosity 3 to 4. In the same position, the net amplitude of the right suprhyoid muscle group when swallowing fluid of viscosity 4 was significantly higher than that with a viscosity of 0 to 1. At viscosity 3 it was significantly higher than with a viscosity of 1.Conclusion:Swallowing fluids of different viscosities in different head positions can affect the contraction of the suprahyoid muscles to different degrees.

Effect of Hand-free “Chin Tuck against Resistance (CTAR)” Exercise on Hyoid Bone Movement and the Degree of Aspiration in Stroke Patients with Dysphagia: A Report of 2 Cases / 대한연하장애학회지

This study recruited two men with dysphagia after stroke, aged 57 and 62 years. They had difficulty using both hands properly due to paralysis of the left upper extremity and rheumatoid arthritis of the right hand in patient 1 and paralysis of both upper extremities in patient 2. This study examined the effects of 4 weeks of hand-free chin-tuck-resistance exercise on the hyoid movement and aspiration. The exercises involved isotonic and isometric parts. In isometric CTAR, the patients were asked to chin tuck against the device 3 times for 60 s each with no repetition. In isotonic CTAR, the patient performed 30 consecutive repetitions by strongly pressing against the resistance device and then releasing it. Based on a video fluoroscopic swallowing study, the degree of aspiration was measured using the Penetration-Aspiration Scale (PAS) and two-dimensional motion analysis of the hyoid bone. Post-intervention, the hyoid movements in both patients improved by 0.16 and 0.22 cm (anterior movement), and 0.26 and 0.28 cm (superior movement), and the PAS scores decreased by 2 and 2 points, respectively. This study confirms that hands-free chin-tuck resistance exercise is applicable and helpful for improving the hyoid movement and reducing aspiration in patients with dysphagia after stroke. Therefore, this exercise can be introduced as an intervention for improving the swallowing function in patients with dysphagia who have difficulty using both hands.

Clinical Application of FES for Swallowing: Intensity Levels and the Placement of Electrode / 대한연하장애학회지

When treating dysphagia, “Functional electrical stimulation” is used for the purpose of improving muscle function, which is useful for swallowing. During swallowing, contraction of suprahyoid muscle is one of the first events that triggers the swallowing reflex and helps the bolus prevent aspiration during swallowing. Moreover, one of the aims of Functional Electrical Stimulation (FES) on the neck is to augment the hyolaryngeal elevation. However, depending on the current intensity and electrodes placement, the outcomes may vary. Although FES is a relatively new treatment method in comparison to traditional treatment techniques for dysphagia, presenting clear evidence and effectiveness is uncertain due to the application of various techniques. Therefore, this study is designed to know the effects of FES according to intensity of stimulation and placement of electrode.

Effect of Treatment after Stimulation of Suprahyoid Muscle in Geriatric Patients with Pharyngeal Dysphagia

Electrical stimulation is recently rising as a treatment protocol of dysphagia. The mechanism is known to induce the pharyngeal reflex to stimulate the sensory nerve around the neck. However, elevation of the hyoid and pharynx to stimulate the suprahyoid muscles (esp. mylohyoid muscle) is thought to be more beneficial. We presented 3 cases to improve the dysphagia after stimulation of the suprahyoid muscles to elevate the hyoid and pharynx similar to the normal swallowing during 4 weeks.