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Expiratory muscle strength training (EMST) is an exercise program designed to strengthen the muscles of expiration by increasing expiratory load during breathing exercises using either resistive or pressure threshold devices. Previous research has shown that EMST may increase submental suprahyoid muscle activity as measured with surface electromyography. The impact of EMST on submental muscles is of interest to those who treat dysphagia. The purpose of this study was to determine whether the cross-sectional area of the geniohyoid muscle changes as observed with ultrasound during a 5-week EMST program performed at 75% of maximum expiratory strength using the EMST150 device in healthy adults. Ten healthy adults participated in the 5-week program. Maximum expiratory pressure (MEP) and cross-sectional area of the geniohyoid muscle were measured weekly. Geniohyoid cross-sectional area was measured from ultrasound images recorded in the coronal plane. Repeated Measures ANOVA was used to determine whether there were significant changes among the dependent variables over the study period. Both MEP and geniohyoid area increased significantly in response to a 5-week program of EMST. EMST in healthy adults is effective at strengthening the geniohyoid muscle as reflected by significantly increased cross-sectional area measured with B-mode ultrasound. This is the first study to document weekly change in muscle morphology as a result of EMST. Increasing geniohyoid muscle mass and consequent strength through a program of EMST may be beneficial for persons with pharyngeal stage dysphagia resulting from reduced hyolaryngeal elevation, reduced laryngeal closure, or reduced UES opening.

Dysphagia is considered a social problem in the super-aging society. However, age-related changes in swallowing-related muscles have not been fully deciphered. We aimed to identify intramuscular fatty infiltration and muscle atrophy in multiple swallowing-related muscles on magnetic resonance imaging (MRI). Moreover, an appropriate muscle strength parameter for the evaluation of swallowing-related muscle mass was examined. We analyzed the Dixon MRI results of 20 elderly and 20 young adults without head and neck cancer, stroke, neuromuscular disease, or whole-body sarcopenia to evaluate intramuscular fatty infiltration (IMF) and lean muscle mass (LMM) in the tongue, geniohyoid, and pharyngeal muscles. The pharyngeal lumen size was also assessed. Tongue pressure, jaw-opening strength, occlusal force, and head-lifting strength were evaluated within a week before and after MRI. Aging significantly affected the IMF of the swallowing-related muscles, and the tongue muscle was most affected, followed by the pharyngeal muscle and then the geniohyoid muscle. Only the LMM of the geniohyoid muscle significantly decreased with aging. The pharyngeal lumen size did not significantly differ between the elderly and young participants, and only tongue pressure was significantly correlated with tongue, geniohyoid, and pharyngeal muscle mass. IMF is primarily associated with age-related composition changes in swallowing-related muscles, and it is commonly observed in the tongue and pharyngeal muscles. The geniohyoid muscle is more at risk of muscle atrophy rather than fatty infiltration. In addition, tongue pressure can be a parameter for the evaluation of swallowing-related muscle mass.

This study aimed to determine whether geniohyoid and/or masseter muscle mass can predict the severity of dysphagia after salvage surgery for head and neck cancer. We conducted a retrospective cohort study of 45 male patients with head and neck cancer (median age, 68 years) who underwent salvage surgery. The preoperative geniohyoid and masseter muscle masses were evaluated using computed tomography and the severity of dysphagia was evaluated by Penetration Aspiration Scale (PAS), Functional Oral Intake Scale (FOIS) and Oropharyngeal swallow efficiency (OPSE). The median PAS, FOIS and OPSE scores after surgery were 7 (interquartile range [IQR] 1–8), 6 (IQR 2–7) and 95.8 (IQR 67.1–116.2), respectively. The mean geniohyoid muscle masses were 3.13 ± 0.78 cm2 and the mean masseter muscle masses were 4.37 ± 0.99 cm2, respectively. The multivariate analysis showed that the geniohyoid muscle mass was significantly associated with the PAS, FOIS and OPSE scores. Conversely, the masseter muscle mass was not significantly associated with the PAS score but was significantly associated with the FOIS and OPSE scores. Geniohyoid muscle mass may predict the severity of dysphagia after salvage surgery.

Objective – of the work is to clarify the sources of germs and find out the chronological sequence of morphogenesis of the muscular structures of the suprahyoid triangles of the anterior cervical region in the embryonic and prefetal periods of human ontogenesis.Material and methods. 25 series of consecutive histological sections of human embryos and prefetuses aged from 5 till 12 weeks of development (6.0-80.0 mm parietal-coccygeal length (PCL)) using a complex methods of morphological examination (anthropometry, morphometry, microscopy, three-dimensional computer reconstruction and statistical analysis) were studied.Results. The rudiment of digastric muscle was first detected in 7-week-old prefetuses (15.5-16.0 mm PCL). The medial surface of Meckel’s cartilage is the site of attachment of the superior belly of the digastric muscle. At the 12th week of intrauterine development, the digastric muscle finally acquires its definitive attachment to the internal surface of the body of mandible. The rudiment of the mylohyoid muscle was first detected in 6-week-old embryos (10.0-12.0 mm PCL). The place of its attachment begins near the mental symphysis, the attachment of the muscle to the anlage of the hyoid bone was detected only at the end of the 7th week of intrauterine development (prefetuses 19.0-20.0 mm PCL). The anlage of the geniohyoid muscle was first determined in the 6-week-old human embryos. In prefetuses of 15.5- 40.0 mm PCL, geniohyoid muscle begins on the medial surface of Meckel’s cartilage, and from the 12th week of intrauterine development (prefetuses 75.0-77.0 mm PCL), the muscle attachment is localized on the internal surface of the body of mandible. The genioglossus muscle is found on the internal and caudal surfaces of Mekel’s cartilage, but from the middle of the 12th week of intrauterine development the site of its attachment moves to the medial-caudal surface of the body of mandible.Conclusions. 1. The anlages of all muscles that delimit the boundaries of the suprahyoid triangles of the neck were identified at the beginning of the 7 th week of intrauterine development (prefetuses 15.5-16.0 mm PCL). 2. The suprahyoid muscles attach to the medial surface of Meckel’s cartilage, but during the 8-11th weeks of intrauterine development, the attachment sites gradually move to the bony edges of the mandible, which cover Meckel’s cartilage. 3. In the prenatal period of development, bundles of the mylohyoid muscle leave the anterior region of the mental symphysis free. 4. In human prefetuses, only the geniohyoid and mylohyoid muscles were attached to the hyoid bone.

We investigated the associations about the mass of geniohyoid and tongue muscle and the maximum tongue pressure in patients with sarcopenic dysphagia using ultrasonography. Cross sectional study. 5 hospitals including 3 acute and 2 rehabilitation hospitals and 1 older facility. 36 inpatients with sarcopenic dysphagia. Ultrasonography was performed for geniohyoid muscle and tongue. The area for geniohyoid and tongue muscles in sagittal plane and the mean brightness level (0–255) in the muscle area were calculated. Maximum tongue pressure as strength of swallowing muscle were investigated. Partial correlation coefficient and multiple regression analysis adjusting for age and sex were performed. The mean age was 81.1 ± 7.9. Men were 23. The mean BMI was 19.0 ± 4.1. The mean maximum tongue pressure was 21.3 ± 9.3 kPa. The mean cross sectional area for geniohyoid muscles was 140 ± 47 mm2. The mean brightness for geniohyoid muscle was 18.6 ± 9.0. The mean cross sectional area for tongue muscles was 1664.1 ± 386.0 mm2. The mean brightness for tongue muscles was 34.1 ± 10.6. There was a significant positive correlation between area of geniohyoid muscle and maximum tongue pressure (r = 0.38, p = 0.04). Geniohyoid muscle area was an explanatory factor for maximum tongue pressure (p = 0.012) and tongue muscle area (p = 0.031) in multivariate analysis. Geniohyoid muscle mass was an independent explanatory factor for maximum tongue pressure and tongue muscle mass.

Background: Recently, a new method of dysphagia rehabilitation using Kinesio taping (KT) has been attempted and demonstrated an immediate increase in the activation of the suprahyoid muscle during swallowing in healthy adults. Objectives: To investigate the effect of dysphagia rehabilitation using KT on the thickness change of the suprahyoid muscle in patients with dysphagia after stroke. Design: Two-group pre-post design. Methods: In this study, 20 patients with dysphagia after stroke were enrolled and assigned to the experimental and control groups. The experimental group applied KT to the front of the neck and repeatedly swallowed against the tension of the tape. On the other hand, the control group performed repeated swallowing without applying KT. Patients in both groups had swallowed 50 times a day/5 times a week for 4 weeks. For evaluation, the volume of the geniohyoid, mylohyoid, and digastric muscle was measured before and after the intervention using portable ultrasound equipment. Results: As a result of comparing the two groups after the intervention, the experimental group showed more volume increase in mylohyoid (P

This study aims to clarify some of the issues associated with the reliable measurement of muscle thickness on ultrasonographic images of the musculoskeletal system, namely the repeatability of measurements in different time frames, the effect of body side selection, and the effect of scan orientation. Ultrasound scans were performed on muscles associated with essential daily activities: geniohyoid, masseter, anterior arm muscles, rectus femoris, vastus intermedius, tibialis anterior, and gastrocnemius. Measurements of the muscle thickness were performed and repeated after 1, 6, and 24 h, on both dominant and nondominant side, using both transverse and longitudinal scans. Thirteen healthy volunteers (eight males and five females, mean age = 24 years, SD = 2.86, range = 19-29) were included. The intraclass correlation coefficient (ICC) was calculated between the baseline and the 1-, 6-, and 24-h interval, using a two-way mixed model of absolute agreement. The ICC ranged from 0.295 for the longitudinal scan of the left masseter muscle in the 6-h interval to 0.991 for the longitudinal scan of the nondominant anterior arm muscles in the 24-h interval. The results indicate that there is variable reliability of the measurements depending on the muscle, time frame, body side, and scan orientation. Consequently, the choice of these parameters can affect the validity of the measurements. Further investigation on a larger scale is required to establish the preferred parameters for each anatomical site.

The activities of the suprahyoid muscles have been reported to be induced by tongue muscle contraction. The purpose of this research was to investigate whether tongue-strengthening exercises using a device cause hypertrophy of the geniohyoid muscle in healthy adults. Seven healthy young adults (3 men and 4 women, 21.0 ± 1.3 years old) received 8-week tongue muscle training with the JMS Tongue Pressure Measuring Device. The participants were instructed to press the anterior tongue against the hard palate 30 times in each session, three sessions a day, and 3 days a week. The exercise intensity was set to 60% of maximum tongue pressure in the first week, and to 80% of maximum tongue pressure for the remaining period. The training effect was evaluated by measuring (1) maximum tongue pressure value with the JMS Tongue Pressure Measuring Device, and (2) the area at rest, shortening amount, and contraction ratio of the geniohyoid muscle using ultrasonic imaging. After the 8-week training program, the maximum tongue pressure increased significantly from 44.9 to 61.6 kPa. The area of the geniohyoid muscle at rest also increased significantly from 2.3 to 2.6 cm2 after the program. There were no significant differences in the shortening amounts and the contraction ratios of the geniohyoid muscle between the values before and after the program. The tongue-strengthening exercise was useful to increase the muscle power of the geniohyoid, as well as the tongue muscles, in healthy young adults.

Objectives/hypothesis Genioglossus advancement is performed in select patients with obstructive sleep apnea. Surgical techniques attempt to capture the genial tubercle of the mandible; however, measurements of the genioglossus, geniohyoid, and digastric muscles are poorly delineated. This investigation is the largest anatomic study exploring the muscles of genial advancement surgery and the first to quantitatively characterize muscular attachments relative to the tubercle, providing new insights from an anatomic perspective on optimizing muscular advancement. Study design Cadaveric study. Methods Fifty-three fresh cadaveric mandibles underwent dissection of the genial tubercle and genioglossus, geniohyoid, and digastric muscles. Results Genial tubercle, geniohyoid, and genioglossus mean height was 7.78 mm, 5.15 mm, and 6.11 mm, respectively. On average, the geniohyoid began 4.88 mm and ended 10.03 mm from the inferior border of the mandible; the genioglossus 11.91 mm and 18.01 mm, similarly. Intermuscular distance, if present, was 2.67 mm; the muscles overlapped in 28% of cadavers. The combined vertical height of the muscles at their mandibular attachment was 13.94 mm, significantly differing from the height of the genial tubercle. The left and right lateral insertion of the digastric muscles was 19.34 mm and 19.31 mm, respectively, from midline. Conclusions The variable range of muscle attachments suggests that genioglossal and geniohyoid attachments extend beyond the genial tubercle and may not originate concentrically from the tubercle, but overlap and lie in very close proximity. Mandibular anterior muscle attachments require anatomic accuracy and an effective operative evaluation of advancement before reproducible, clinically effective osteotomies can be recommended. Level of evidence NA Laryngoscope, 129:2424-2429, 2019.

Highlights • The literature scarcely describes high anterior neck approaches to deep intra-glossal foreign bodies, tending to focus on transoral removal. • This case describes an approach that is utilised in insertion of bilateral hypoglossal nerve stimulators. • The approach includes midline transcervical incision, and exposure and midline separation of mylohyoid and geniohyoid muscles to expose genioglossi muscles. • This approach carries low morbidity compared to transoral approaches despite traditional dogma mandating avoidance of open neck approaches., Introduction and importance In the era of both new bilateral hypoglossal nerve stimulator and long-standing experience with Sistrunk’s procedures, it is notable that the literature scarcely describes high anterior neck approaches, tending to focus on transoral removal of intra-glossal foreign bodies. Herein we describe a case of a low morbidity anterior approach for access to an intra-glossal foreign body and discuss the implications. Case presentation A morbidly obese 73 year old lady presented acutely after inadvertent ingestion of a sewing needle. Initial assessment demonstrated an intraglossal foreign body which subsequently migrated into the deep substance of the tongue. Endoscopic retrieval was attempted but was unsuccessful. A midline transcervical anterior neck incision was made, exposure and midline separation of mylohyoid, and midline dissection of geniohyoid muscles was performed to expose genioglossi muscles and the foreign body removed. The patient recovered well without complication. Clinical discussion This approach carries low morbidity compared to transoral approaches despite traditional dogma mandating avoidance of open neck approaches. Such approaches have recently been developed for implantation of bilateral hypoglossal nerve stimulators. Conclusion Otolaryngologists should consider midline transcervical approach to retrieve deep intra-glossal foreign bodies, particularly in scenarios where other options may not provide adequate access or may enhance intra-oral morbidity.

The use of maxillofacial osteotomies for the treatment of dentofacial deformities has a long and storied history. Movement of the maxilla, mandible, and chin can be performed in all three planes of space in order to achieve the appropriate skeletal changes. Historically, surgeons anecdotally noted improvement in patient-reported signs and symptoms of daytime somnolence, snoring, and nighttime observations of apneic episodes by bed partners in a subset of their orthognathic surgical patients. As such, it becomes clear over time that osseous advancement of the facial bones could provide relief of airway obstruction. The use of maxillofacial osteotomies to manage the patient with PAP-intolerant obstructive sleep apnea has been validated both as a rescue treatment for patients failing other types of OSA procedures (such as UPPP) and as a primary treatment. Such treatments advance the osseous insertion points of soft tissues that support airway patency. Specifically, anterior movement of the maxilla advances the soft palate, superior aspect of the pterygomandibular raphe, and associated connections to the superior pharyngeal constrictor while also permitting intra-nasal modifications such as septoplasty, removal of bone spurs, osseous recontouring, and turbinoplasty. Advancement of the mandible and chin directly advances the attachments of the genioglossus, geniohyoid, mylohyoid, digastric muscles, and the inferior aspect of the pterygomandibular raphe.

BACKGROUND Sarcopenia is a common disease in the elderly. Although extensive research has been conducted on muscle mass and quality assessment tools, there are still certain drawbacks preventing their universal use. AIM The aim of this study was the evaluation of the thickness of head, neck, upper and lower limb muscles measured with ultrasonography, as a potential predictory tool in sarcopenia. DESIGN Prediction study. SETTING The Outpatient Sarcopenia Clinic of the Rehabilitation Department of the University Hospital of Patras. POPULATION Ninety-four individuals (27 men and 67 women) with a mean age of 75.6 years (SD=6.6), referred for sarcopenia screening, participated in this study. METHODS The muscle thickness was measured with transverse and longitudinal ultrasound scans bilaterally. RESULTS The thickness of the geniohyoid and medial head of gastrocnemius muscle in all ultrasound sections, and the thickness of the rectus femoris and vastus intermedius muscle, in specific sections, was found to be significantly decreased in patients with sarcopenia (P

Aim: Jaw-opening strength is an indicator of swallowing function including hyoid bone elevation. Geniohyoid muscles play an important role during hyoid bone elevation. This study aimed to investigate whether geniohyoid muscle thickness and echo intensity measured by ultrasonography were related to jaw-opening strength.Material and methods: Sixty-eight participants (39 men) with an average age of 77±7.7 years were recruited from a functional training health care facility. We measured muscle thickness and echo intensity of the geniohyoid muscle on transverse ultrasound images.Results: Age, calf circumference, grip strength, muscle thickness and echo intensity were significantly associated with jaw-opening strength in univariate analyses. After adjusting for grip strength in multiple regression analysis, geniohyoid muscle thickness and echo intensity were significantly associated with jaw-opening strength (β=0.29 for muscle thickness, β=−0.26 for echo intensity).Conclusions: There was a positive correlation between geniohyoid muscle thickness and jaw-opening strength; echo intensity negatively correlated with jaw-opening strength. Ultrasound evaluation of geniohyoid muscle status provides important information about maintaining jaw-opening strength.

OBJECTIVES Persistent or recurrent disease following excision of a thyroglossal duct cyst/sinus (TGDC) is often found in the suprahyoid region. Cadaver dissections were performed to identify and name important surgical landmarks in the suprahyoid area; a histopathologic analysis of surgical specimens was completed to determine the incidence and extent of microscopic disease; and clinical outcomes were compared to determine the efficacy of a specific anatomic dissection. STUDY DESIGN Retrospective case series. METHODS Standardized dissections of four adult cadavers were performed. Consecutive surgical specimens were examined for evidence of microscopic TDGC disease in the suprahyoid region, measuring the greatest width and length of disease. A retrospective review of all consecutive TGDC procedures was completed. RESULTS The important surgical landmarks in the suprahyoid area were identified in all cadavers. Microscopic disease in the suprahyoid area was found in 79% (37 of 47) of surgical specimens. The mean greatest length and width of microscopic disease was 12.4 mm and 1.4 mm, respectively. Following identification of these landmarks, the incidence of recurrent or persistent disease decreased (P = .02) from 5% (8 of 159) to 0% (0 of 112). CONCLUSION The majority of pediatric patients with a TGDC will have microscopic disease in the suprahyoid area. The surgical landmark of the fascial plane between the geniohyoid and genioglossus muscles demarcates the anterior and lateral borders of resection in the suprahyoid area. This approach can be used as a reliable and easily reproducible technique in TGDC surgery to increase confidence of achieving complete removal of disease in the suprahyoid area, avoiding persistent or recurrent disease and a revision procedure. LEVEL OF EVIDENCE 4 Laryngoscope, 131:553-558, 2021.

Afferent feedback can appreciably alter the pharyngeal phase of swallow. In order to measure the stability of the swallow motor pattern during several types of alterations in afferent feedback, we assessed swallow during a conventional water challenge in four anesthetized cats, and compared that to swallows induced by fixed (20 Hz) and stochastic (1-20Hz) electrical stimulation applied to the superior laryngeal nerve. The swallow motor patterns were evaluated by electromyographic activity (EMG) of eight muscles, based on their functional significance: laryngeal elevators (mylohyoid, geniohyoid, and thyrohyoid); laryngeal adductor (thyroarytenoid); inferior pharyngeal constrictor (thyropharyngeus); upper esophageal sphincter (cricopharyngeus); and inspiratory activity (parasternal and costal diaphragm). Both the fixed and stochastic electrical stimulation paradigms increased activity of the laryngeal elevators, produced short-term facilitation evidenced by increasing swallow durations over the stimulus period, and conversely inhibited swallow-related diaphragm activity. Both the fixed and stochastic stimulus conditions also increased specific EMG amplitudes, which never occurred with the water challenges. Stochastic stimulation increased swallow excitability, as measured by an increase in the number of swallows produced. Consistent with our previous results, changes in the swallow motor pattern for pairs of muscles were only sometimes correlated with each other. We conclude that alterations in afferent feedback produced particular variations of the swallow motor pattern. We hypothesize that specific SLN feedback might modulate the swallow central pattern generator during aberrant feeding conditions (food/liquid entering the airway), which may protect the airway and serve as potentially important clinical diagnostic indicators.

AIM The mylohyoid muscle is often believed to exhibit high physiologic fluoro-deoxy-glucose (FDG) uptake. Aim of this study was to use PET/MR for adequately assessing the normal FDG distribution in floor of the mouth (FOM) muscles and neighboring major salivary glands. MATERIALS AND METHODS Patients scanned with a simultaneous PET/MRI system for initial staging or follow-up of head and neck tumors, with no malignant lesions in salivary glands or in FOM, were included. Volumes-of-interest (VOIs) were positioned separately for bilateral mylohyoid, digastric, genioglossus, and geniohyoid muscles, based on T2-weighted and T1-weighted images, and for bilateral parotid, submandibular, and sublingual glands in the same way. SUVmax was measured for each VOI. RESULTS Six hundred and ninety-two VOIs were positioned. FDG uptake in mylohyoid (SUVmax = 1.94 ± 0.37) and digastric muscles (SUVmax = 2.01 ± 0.37) were significantly higher compared to that in geniohyoid (SUVmax = 1.67 ± 0.53) and genioglossus muscles (SUVmax = 1.75 ± 0.54) (Friedman's test; P

Purpose To clarify the effect of geniohyoid (GH) muscle morphology and related function on masticatory ability using a decision-tree analysis. Materials and methods A total of 103 participants were enrolled. A cross-sectional area (CSA) of the GH muscle, neck circumference, body mass index, tongue pressure, jaw opening strength, and masticatory ability score were measured. The CSA of the GH muscle was selected as an independent variable for the first layer of the decision tree, with masticatory score as the dependent variable. Results and conclusion These data suggest that the CSA of the GH muscle may have a large impact on the masticatory ability score when evaluating masticatory ability.

Background The classical anatomical representation of the lingual relief of the mental region of the mandible reflects the presence of geniohyoid as well as genioglossus attachment areas, which are divided into two or single areas. The International Anatomical Terminology (contains references to the presence of upper and lower spinae mentales, but the terminology does not reflect the content of these structures. The aim of this study was to examine and classify the lingual canals of the mental region. Materials and methods Using a Sirona ORTHOPHOS XG 3D tomograph (isotropic voxel size 0.1 in high-resolution mode) and KaVo 3D eXam cone beam computed tomography, the mental region of the mandible was analyzed in 561 patients aged 18–75 years with regard to bone density and the occurrence of a canal opening on the lingual side of the mandible. In order to visualize the mental spine area, another 50 mandibles were analyzed, divided into two groups of 25 mandibels each: 25 native and 25 dry preparations. Results By prevalence the following channel types were classified: in 33% type I (narrow); in 32% type II (double) and of these in 17.5% (convergent) and type IIb in 14.5% a type IIb subtype (non-convergent); in 14% type III (wide); in 12% type IV (hook-shaped) and in 9% type V (diverging channel), identifying three combined components: the system of channels of the superior and inferior mental spine, and the transversal intraosseous canal of the mental region of the mandible. Conclusions Our anatomical and radiological approach allowed us to suggest a new classification of intraosseous organization of the anterior part of the human mandible. As a result of studying X-ray anatomical and anatomical-topographical, constitutional-based, structural features of the mandible, intraosseous structures of the anterior mandible were clarified and classified, which solve not only terminological disputes, but also are important clinical guidelines for bone surgery, prosthetics, traumatology, endodontic treatment, dental implantation and local anesthesia.

Background Sarcopenic dysphagia is characterized by difficulty swallowing due to a loss of whole-body skeletal and swallowing muscle mass and function. However, no study has reported on swallowing muscle mass and quality in patients with sarcopenic dysphagia. Objective To compare the differences in swallowing muscle mass and quality between sarcopenic and nonsarcopenic dysphagia. Method A cross-sectional study was performed in 55 older patients, who had been recommended to undergo dysphagia assessment and/or rehabilitation. Sarcopenic dysphagia was diagnosed using a diagnostic algorithm for sarcopenic dysphagia. The thickness and area of tongue muscle and geniohyoid muscle (coronal plane and sagittal plane), and the echo-intensity of the tongue and geniohyoid muscles were examined by ultrasound. Results The study participants included 31 males and 24 females (mean age of 82 ± 7 years), with 14 having possible sarcopenic dysphagia, 22 probable sarcopenic dysphagia, and 19 without sarcopenic dysphagia. The group with sarcopenic dysphagia had a significantly lower cross-sectional area and area of brightness of the tongue muscle than that observed in the group without sarcopenic dysphagia. The most specific factor for identifying the presence of sarcopenic dysphagia was tongue muscle area (sensitivity, 0.389; specificity, 0.947; cut-off value, 1536.0), while the factor with the highest sensitivity was geniohyoid muscle area brightness in sagittal sections (sensitivity, 0.806; specificity, 0.632; cut-off value, 20.1). Multivariate logistic regression analysis showed that the area of the tongue muscle and its area of brightness were independent risk factors for sarcopenic dysphagia. However, geniohyoid sagittal muscle area and area of brightness showed no significant independent association with sarcopenic dysphagia. Conclusion Tongue muscle mass in patients with sarcopenic dysphagia was smaller than that in patients without the condition. Sarcopenic dysphagia was also associated with increased intensity of the tongue muscle.

Koalas are characterised by a highly unusual vocal anatomy, with a descended larynx and velar vocal folds, allowing them to produce calls with disproportionately low frequencies. Here we use advanced imaging techniques, histological data, classical macroscopic dissection and behavioural observations to provide the first detailed description and interpretation of male and female koala vocal anatomy. We show that both males and females have an elongated pharynx and soft palate, resulting in a permanently descended larynx. In addition, the hyoid apparatus has a human-like configuration in which paired dorsal, resilient ligaments suspend the hyoid apparatus from the skull, while the ventral parts tightly connect to the descended larynx. We also show that koalas can retract the larynx down into the thoracic inlet, facilitated by a dramatic evolutionary transformation of the ventral neck muscles. First, the usual retractors of the larynx and the hyoid have their origins deep in the thorax. Second, three hyoid muscles have lost their connection to the hyoid skeleton. Third, the genioglossus and geniohyoid muscles have greatly increased in length. Finally, the digastric, omohyoid and sternohyoid muscles, connected by a common tendinous intersection, form a guiding channel for the dynamic down-and-up movements of the ventral hyoid parts and the larynx. We suggest that these features evolved to accommodate the low resting position of the larynx and assist in its retraction during call production. We also confirm that the edges of the intra-pharyngeal ostium have specialised to form the novel, extra-laryngeal velar vocal folds, which are much larger than the true, intra-laryngeal vocal folds in both sexes, but more developed and specialised for low frequency sound production in males than in females. Our findings illustrate that strong selection pressures on acoustic signalling not only lead to the specialisation of existing vocal organs, but can also result in the evolution of novel vocal structures in both sexes.

Objective To present a case of spontaneous fracture of the genial tubercles of the mandible and a review of the literature. Background Resorption of the mandible is well documented in edentulous patients. During this process, the genial tubercles, origin for both genioglossus and geniohyoid muscles, become more prominent and prone to trauma especially from poorly fitted lower full dentures and lead to fracture and separation of the genial tubercles from the mandible. Materials and methods An 85 year old patient with the above presentation was monitored and documented to present this case report. A literature search was carried out to identify any previous reports of this type of fracture, and their diagnosis and treatment modalities. Results This case is extremely rare with only 17 cases reported in the literature. Conclusion Although rare, fractured genial tubercles should be considered in the differential diagnosis for a painful swelling in the floor of the mouth in the edentulous patient.

Submental muscles (i.e. mylohyoid and geniohyoid) play a vital role during swallowing, protecting the airway from ingested material. To design therapies to reduce the functional deficits associated with radiation treatment relies in part on our understanding of the changes in the cytokine and growth factor response that can impact muscle function. The purpose of this study is to quantify changes in the inflammatory, pro-fibrotic, and pro-angiogenic factors following 48Gy of fractionated radiation to the mylohyoid muscle. We hypothesized that (1) irradiation will provoke increases in TGF-1β and MMP-2 mRNA in the mylohyoid muscle; and (2) muscles surrounding the target location (i.e. geniohyoid and digastric muscles) will exhibit similar alterations in their gene expression profiles. Rats were exposed to 6 fractions of 8Gy using a 6MeV electron beam on a clinical linear accelerator. The highest dose curve was focused at the mylohyoid muscle. After 2-and 4-weeks post-radiation, the mylohyoid, geniohyoid, and digastric muscles were harvested. Expression of TNF-α, IFNγ, IL-1β, IL-6, TGF-1β, VEGF, MMP-2, and MMP-9 mRNA was analyzed via PCR and/or RT-PCR. TGF-1β, MMP-2, and IL-6 expression was upregulated in the irradiated mylohyoid compared to nonirradiated controls. No notable changes in TNF-α, IFNγ, and IL-1β mRNA expression was observed in irradiated muscles. Differing expression profiles were found in the surrounding muscles post-radiation. Results demonstrated that irradiation provokes molecular signals involved in the regulation of the extracellular matrix, which could lead to fibrosis or atrophy in the swallowing muscle after radiation.

Purpose: The most crucial airway protection mechanism during swallowing is adequate laryngeal elevation. Suprahyoid muscles are responsible for laryngeal elevation. Our study aimed to compare the effects of three different exercises, Shaker, resistance chin tuck (CTAR) exercise, and chin tuck exercise with theraband, on suprahyoid muscles activity responsible for laryngeal elevation. Methods: Forty-two healthy subjects with a mean age of 27.92 +/- 5.02 years (18-40 years), of which 50% were male were included. All individuals were divided into three groups with computerized randomization. Surface Electromyography (EMG) evaluation was performed to determine electrical activity of the suprahyoid muscles (geniohyoid, mylohyoid, anterior belly of digastric, thyrohyoid, stylohyoid muscles) during maximal voluntary isometric contraction and during performing CTAR, Shaker exercise and chin tuck with theraband. Normalized suprahyoid muscle activations were calculated as the recorded maximum electrical activity during exercise (mV)/recorded maximum electrical activity during maximum isometric contraction (mV). Results: A statistically significant difference was found between three groups regarding normalized suprahyoid muscle activation (p

Naked mole-rats (Heterocephalus glaber) are fossorial, eusocial rodents that exhibit the unusual capability of moving their lower incisors independently in lateral and rostroventral directions. The evolution of this trait would presumably also involve concurrent alterations in neck musculature to support and control movements of the lower incisors. In order to assess morphological adaptations that might facilitate these movements, we performed detailed dissections of the neck musculature of adult naked mole-rats. In addition to characterizing attachment sites of superficial, suprahyoid, and infrahyoid musculature, we also quantified muscle mass and mandibular features thought to be associated with gape (condyle height, condyle length, and jaw length). Based on muscle attachment sites, the platysma myoides may contribute to lateral movement of the lower incisor and hemi-mandible in naked mole-rats. The large digastric muscle is likely to be a main contributor to rostroventral movement of each lower incisor. The geniohyoid and mylohyoid muscles also likely contribute to rostroventral movements of the lower incisors, and the mylohyoid may also produce lateral spreading of the hemi-mandibles. The transverse mandibular (intermandibularis) muscle likely serves to reposition the lower incisors back to a midline orientation following a movement.

The aim of the present study is to evaluate the early and long-term postoperative dimensional changes of the muscles of the mandible in patients with orthognathic surgery for class II and class III malocclusions by using ultrasonography (US). Twenty-six patients who underwent bimaxillary orthognathic surgery for class II or class III malocclusions (14 and 12 patients, respectively) were ultrasonographically examined. The length, width, and cross-sectional area of the masseter and suprahyoid muscles were measured at three different time points: T0 (preoperatively), T1 (early postoperatively at 1 month after the surgery), and T2 (late postoperatively at 9 months). A repeated measures ANOVA was used to calculate statistically significant dimensional changes of the mandibular muscles. Statistically significant dimensional changes were found postoperatively in class II malocclusion patients only. The digastric muscle showed higher values for the length and lower values for the width (p

Dermoid cysts are benign cutaneous neoplasms that contain germ cells from the ectoderm and mesoderm. Approximately 70% are diagnosed during childhood before the age of 5. Although they can present throughout the body, the prevalence is 7% for those arising from the head and neck. These lesions present primarily as midline masses and are classified as sublingual, submental, or overlapping depending on their relationship with the muscles of the floor of mouth. A 10-year-old female presented with a 2-week history of right submental swelling. She denied pain, dysphagia, odynophagia, or respiratory distress. Physical examination showed nontender fullness of the submental region without erythema or induration and no palpable cervical lymphadenopathy. Ultrasound showed an oval-shaped cystic mass measuring 4.8 × 4.0 × 2.6 cm. After a course of clindamycin, a computed tomography was obtained which showed a right 4.5 × 4.0 × 2.6 cm fluid filled lesion, within the right lateral floor of mouth. Intraoral resection was performed and the mass was freed from the geniohyoid and mylohyoid. Histopathology was consistent with a dermoid cyst. Submental masses have a broad differential, but rarely are they dermoid cysts if they arise lateral to the midline. With appropriate diagnosis and total surgical excision, patients and their families can be reassured in similar cases.

Swallow is a complex behavior that consists of three coordinated phases: oral, pharyngeal, and esophageal. Esophageal distension (EDist) has been shown to elicit pharyngeal swallow, but the physiologic characteristics of EDist-induced pharyngeal swallow have not been specifically described. We examined the effect of rapid EDist on oropharyngeal swallow, with and without an oral water stimulus, in spontaneously breathing, sodium pentobarbital anesthetized cats (n = 5). Electromyograms (EMGs) of activity of 8 muscles were used to evaluate swallow: mylohyoid (MyHy), geniohyoid (GeHy), thyrohyoid (ThHy), thyropharyngeus (ThPh), thyroarytenoid (ThAr), cricopharyngeus (upper esophageal sphincter: UES), parasternal (PS), and costal diaphragm (Dia). Swallow was defined as quiescence of the UES with overlapping upper airway activity, and it was analyzed across three stimulus conditions: 1) oropharyngeal water infusion only, 2) rapid esophageal distension (EDist) only, and 3) combined stimuli. Results show a significant effect of stimulus condition on swallow EMG amplitude of the mylohyoid, geniohyoid, thyroarytenoid, diaphragm, and UES muscles. Collectively, we found that, compared to rapid cervical esophageal distension alone, the stimulus condition of rapid distension combined with water infusion is correlated with increased laryngeal adductor and diaphragm swallow-related EMG activity (schluckatmung), and post-swallow UES recruitment. We hypothesize that these effects of upper esophageal distension activate the brainstem swallow network, and function to protect the airway through initiation and/or modulation of a pharyngeal swallow response.

Objectives/Hypothesis To assess the effect of genioglossus, geniohyoid, and anterior digastric muscle advancement on base of tongue and hyoid position. Study Design Cadaver experiments. Methods In fresh cadavers, the mandibular attachments of the genioglossus, geniohyoid, and anterior digastric muscles were advanced anteriorly by 6, 10, or 14 mm, and the anterior displacement of the base of tongue and hyoid was measured. The degrees of displacement of the tongue base and hyoid by the individual muscles and combinations of muscles were compared to one another. Results In 11 cadavers, 462 measurements were taken. Genioglossus advancement alone produced significantly greater tongue base advancement than any other muscle (P < .001). No combination of muscles produced significantly more tongue base advancement than the genioglossus alone. Geniohyoid (P < .001) and anterior digastric muscle (P < .001) advancement both produced significantly greater hyoid advancement than the genioglossus, but there was no difference between the two (p = .615). No combination of muscles produced significantly more hyoid advancement than the geniohyoid or anterior digastric alone. Conclusions Genioglossus muscle advancement produces the greatest base of tongue advancement. Geniohyoid or anterior digastric muscle advancement produces the greatest hyoid advancement. Advancement of neither base of tongue nor hyoid was superior when combinations of muscles were moved. Level of Evidence NA Laryngoscope, 127:1938–1942, 2017

Dermoid and epidermoid cysts occur in the head and neck region with an incidence of 6.9e7%. 2,3 About 11.5% of dermoid cysts of the head and neck appear in the floor of the mouth, the second most common location after the floor of the mouth being the cervical region and rarely in the tongue. They represent less than 0.01% of all oral cavity cysts. 4 Usually lingual dermoid cysts are discovered at birth or at the first year of life. However, when they are developed on the ventral surface of the tongue, their clinical appearance will be much later in childhood or at early adult life. Anatomic classification divides the epidermoid cysts of the floor of the mouth into three groups according to their relation to the muscles of the floor of the mouth: sublingual or median genioglossal cysts, located above the geniohyoid muscles; median geniohyoid cysts, located in the submental region between the geniohyoid and the mylohyoid muscles; and lateral cysts, located in the submaxillary region. 5 We present the clinical, histological findings and management of epidermoid cyst on ventral surface of the tongue in a 12-year-old boy.

© 2020 Yang et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Purpose To automate the estimation of swallowing motion from 2D MR cine images using deformable registration for future applications of personalized margin reduction in head and neck radiotherapy and outcome assessment of radiation-associated dysphagia. Methods Twenty-one patients with serial 2D FSPGR-MR cine scans of the head and neck conducted through the course of definitive radiotherapy for oropharyngeal cancer. Included patients had at least one cine scan before, during, or after radiotherapy, with a total of 52 cine scans. Contours of 7 swallowing related regions-of-interest (ROIs), including pharyngeal constrictor, epiglottis, base of tongue, geniohyoid, hyoid, soft palate, and larynx, were manually delineated from consecutive frames of the cine scan covering at least one swallowing cycle. We applied a modified thin-plate-spline robust-point-matching algorithm to register the point sets of each ROI automatically over frames. The deformation vector fields from the registration were then used to estimate the motion during swallowing for each ROI. Registration errors were estimated by comparing the deformed contours with the manual contours. Results On average 22 frames of each cine scan were contoured. The registration for one cine scan (7 ROIs over 22 frames) on average took roughly 22 minutes. A number of 8018 registrations were successfully batch processed without human interaction after the contours were drawn. The average registration error for all ROIs and all patients was 0.36 mm (range: 0.06 mm– 2.06 mm). Larynx had the average largest motion in superior direction of all structures under consideration (range: 0.0 mm– 58.7 mm). Geniohyoid had the smallest overall motion of all ROIs under consideration and the superior-inferior motion was larger than the anterior-posterior motion for all ROIs. Conclusion We developed and validated a deformable registration framework to automate the estimation of swallowing motion from 2D MR cine scans.

Introduction: Accurate knowledge of anatomic characteristics and variations of sonographic view is important to better understand the imaging findings for a more precise examination. The present study therefore aimed to examine the variations in sonographic view of the normal anatomy of salivary glands and the important anatomical structures around them. Material and Methods: In this study, 200 cases of parotid, submandibular, and sublingual salivary glands in 100 healthy volunteers were scanned using ultrasound. The variables studied included echogenicity and echo-pattern of all three pairs of salivary glands, borders of submandibular and sublingual glands, and the possibility of observing common tissues, which were evaluated in all examinations. Results: Eighty-three female and 17 males were surveyed between the ages of 6 and 61. Echogenicity of the sublingual, submandibular, and parotid glands was hyperechoic in 94.5%, 92.5%, and 84.5%; and hypoechoic in 5.5%, 7.5% and 15.5%, respectively. Also, echo-pattern of the sublingual, submandibular, and parotid glands was homogeneous in 78.5%, 80.5%, and 92%; and heterogeneous in 21.5%, 19.5% and 8%, respectively. The border of sublingual glands was well, ill, and poor in 36.5%, 43.5%, and 20%, respectively. Also, the border of submandibular glands was well, ill, and poor in 56%, 24.5%, and 19.5%, respectively. In the possibility of observing sublingual gland-specific variables, the highest and lowest frequency was related to geniohyoid with 73% and genioglossus with 50.5%, respectively. In submandibular glands, the highest and lowest frequency was of posterior digastric belly with 69.5% and hyoglossus muscle with 60%, respectively. Also, in parotid gland, the highest and lowest frequency was related to lymph nodes with 56% and external carotid artery with 32%, respectively. Conclusion: There were significant variations in the sonographic characteristics of all three pairs of salivary glands of healthy volunteers, indicating that accurate knowledge of the glands is necessary for reliable ultrasound examination.

Anatomical connections are reported between the cerebellum and brainstem nuclei involved in swallow such as the nucleus tractus solitarius (NTS), nucleus ambiguus, and Kölliker-fuse nuclei. Despite these connections, a functional role of the cerebellum during swallow has not been elucidated. Therefore, we examined the effects of cerebellectomy on swallow muscle recruitment and swallow-breathing coordination in anesthetized freely breathing cats. EMG recordings were collected from upper airway, pharyngeal, laryngeal, diaphragm, and chest wall muscles before and after complete cerebellectomy. Removal of the cerebellum reduced the excitability of swallow (i.e. swallow number), and muscle recruitment of the geniohyoid, thyroarytenoid, parasternal (chestwall), and diaphragm muscles, but did not disrupt swallow-breathing coordination. Additionally, diaphragm and parasternal muscle activity during swallow is reduced after cerebellectomy, while no changes were observed during breathing. These findings suggest the cerebellum modulates muscle excitability during recruitment, but not pattern or coordination of swallow with breathing.

Upper airway patency to airflow and the occurrence of obstructive sleep apnea involve a complex interplay between pharyngeal anatomy and synergic co-activation of peri-pharyngeal muscles. In previous studies we observed large differences in the response to sleep-associated flow limitation between the genioglossus and other (non-GG) peri-pharyngeal muscles. We hypothesized that similar differences are present also during wakefulness. In the present study we compared the response to inspiratory loading of the genioglossus electromyogram and four other peri-pharyngeal muscles. Studies were performed in eight obstructive sleep apnea patients, seven age-matched healthy subjects and five additional younger subjects. Electromyogram activity was evaluated over a range of negative oesophageal pressures and expressed as % of maximal electromyograms. In healthy subjects, the slope response to inspiratory loading (electromyogram/pressures) was similar for the genioglossus and non-GG muscles studied. However, the electromyogram responses were significantly higher in the young subjects compared with older subjects. In contrast, in the obstructive sleep apnea patients, the electromyogram/pressure response of the non-GG muscles was similar to that of the age-matched healthy subjects, whereas the slope response of the genioglossus electromyogram was significantly higher than non-GG muscles. We conclude that both age and the presence of obstructive sleep apnea affect the response of peri-pharyngeal muscles to inspiratory loading. In patients with obstructive sleep apnea the genioglossus seems to compensate for mechanical disadvantages, but non-GG muscles apparently are not included in this neuromuscular compensatory mechanism. Our current and previous findings suggest that attempts to improve obstructive sleep apnea with myofunctional therapy should put added emphasis on the training of non-GG muscles.

INTRODUCTION: Treatment for TMJ Ankylosis aims at restoring joint function, improving the patient’s aesthetic appearance and quality of life and preventing re-ankylosis. Mouth opening is achieved by gap arthroplasty with various options of interpositional materials. Ramus–condyle unit (RCU) reconstruction maintains the height of the ramus and prevents secondary occlusal problems. Advancement genioplasty corrects chin deformities as well as increases the posterior airway space (N-PAS) by the forward pull exerted on geniohyoid and genioglossus. MATERIALS AND METHODS: This prospective single-centre study on 43 joints in 25 adult patients with TMJ Ankylosis aimed at providing a single-staged management plan of ankylosis release, RCU reconstruction and extended advancement centering genioplasty. Interpositional arthroplasty was done using temporalis myofascial flap, abdominal dermis fat or buccal fat pad. RCU reconstruction was done either by vertical ramus osteotomy or L osteotomy. OBSERVATIONS AND RESULTS: Follow-up ranged from 12 to 20 months (mean 14.4). Average mouth opening at maximum follow-up was 34.36 mm with re-ankylosis in no case. Cephalometric parameters showed increase in point P to Pog, decrease in N perpendicular to Pog, angle N–A–Pog, Cg-ANS to Cg-Menton, neck–chin angle and labiomental angle. N-PAS increased, and average 50% improvement in AHI was seen in all patients with OSA. Most common complications involved transient paraesthesia of temporal and zygomatic branches of facial nerve. CONCLUSION: Based on the findings of the above study, we propose treatment guidelines for treatment of TMJ ankylosis in adult patients with AHI

Purpose There is a lack of anatomic comparisons between maxillomandibular advancement (MMA) and other bony surgical treatments of obstructive sleep apnea (OSA). Surgical procedures were simulated in cadavers to evaluate their ability to expand the posterior airway space (PAS). Materials and Methods The following bony advancement surgeries were performed on each of 9 cadavers: genioglossal advancement (GGA); genioplasty with advancement of the genioglossus, geniohyoid, and anterior digastric muscles (GPA); bilateral sagittal split osteotomy; Le Fort I maxillary advancement; Le Fort I maxillary anterior impaction osteotomy (LFAI); MMA; MMA plus GPA; and MMA plus LFAI. Bony advancements were performed at increasing distances and change in PAS anteroposterior (AP) diameter was measured at the levels of the velum, oropharynx, and hypopharynx. Results Change in PAS varied in a linear fashion with advancement surgical maneuvers. GPA led to a greater increase in AP distance at the levels of the oropharynx and hypopharynx compared with GGA. LFAI showed a greater increase in AP distance at the velum compared with MMA. All maxillary movements showed greater AP expansion in the PAS at the velum compared with mandibular advancements. Conclusions Static AP expansion of the PAS at the levels of the velum, oropharynx, and hypopharynx occurs in a roughly linear and predictable pattern with different bony surgical procedures used in OSA surgery. MMA alone and MMA plus GPA had the overall greatest effect at all airway levels. GPA had a greater effect on expansion of the oropharynx and hypopharynx compared with GGA.

Objectives/Hypothesis The geniohyoid muscle plays an important role in hyoid bone movement. Adequate hyoid bone movement during swallowing is important for effective bolus flow and pharyngeal clearing. The aim of this study was to estimate the relationship between the geniohyoid muscle size and function and hyoid bone movement during swallowing in healthy young adults, as measured via ultrasound, in different body positions. Study Design Cross-sectional study. Methods Forty young (20–40 years old) adults (20 male and 20 female) participated. The cross-sectional area of the geniohyoid muscle at rest (seated position), the geniohyoid muscle contraction velocity, and the hyoid bone displacement during swallowing 10 mL of mineral water were measured by ultrasound in seated, supine, and right lateral decubitus positions. Results The size of the geniohyoid muscle correlated with body height. Males had larger geniohyoid cross-sectional area than females and greater maximal and anterior hyoid displacement during swallowing than females, and maximal and anterior hyoid bone displacement during swallowing correlated with the size of geniohyoid muscle only when the body was in the supine position; these two movements were positively correlated to each other. Conclusions Genders vary in hyoid bone movement during swallowing, and the correlation between geniohyoid muscle size and hyoid bone displacement varies among different body positions during swallowing. This investigation also illuminates the use of ultrasound in providing quantitative measures of geniohyoid muscle and hyoid bone displacement during swallowing. Level of Evidence 2c. Laryngoscope, 125:1886–1891, 2015

Background and ObjectiveaaWe evaluated possibility of modified jaw thrust maneuver with drug induced sleep endoscopy (DISE), as an indicator of mandibular advancement treatment such as mandibular advance device, geniohyoid advancement and other treatment modalities. MethodsaaSixty seven Korean male, obstructive sleep apnea patient, confirmed by full night polysomnography were enrolled. We per formed DISE and analyzed obstruction sites before and after modified jaw thrust maneuver. Degree of improvement in obstruction more than one grade of obstruction, was defined as “responder by modified jaw thrust maneuver”. Non-responder was defined as the airway does not open by the modified jaw thrust maneuver. Association was analyzed among the patient’s characteristics [body mass in dex (BMI), Friedman stage, and respiratory disturbance index (RDI)] and the results. ResultsaaIn retropalatal level obstruction, responder by modified jaw thrust maneuver was most commonly observed at antero-poste rior (AP) obstruction (70.31%) while it was least observed at combined obstruction (66.67%). In retroglossal level obstruction, responder by modified jaw thrust maneuver was most commonly observed at AP obstruction (77.50%), while lateral obstruction was least ob served (68.75%). Between group comparisons including, group of responder and group of non-responder of combined obstruction of retropalatal level and lateral obstruction of retroglossal level, revealed that there were no statistically significant differences in BMI, Friedman stage, and RDI (p < 0.05). ConclusionsaaAirway obstruction did not extend to the same pattern by modified jaw thrust maneuver. Modified jaw thrust maneu ver under DISE is a useful diagnostic tool and predictor of therapeutic effects of mandibular advancement treatment. Sleep Med Res 2014;5(2):49-53

We conducted a clinical cross-sectional study to examine the relationship between jaw-opening force and the cross-sectional area of the suprahyoid muscles and whole skeletal muscle mass. Subjects were healthy 39 males and 51 females without dysphagia and sarcopenia, aged 65 years and older. Jaw-opening force was measured three times using a jaw-opening sthenometer; the maximum of these three was taken as the measurement value. The cross-sectional area of the geniohyoid and anterior belly of the digastric muscles were evaluated using ultrasonography. The skeletal muscle mass index, gait speed and grip strength were evaluated according to the diagnostic criteria of the Asian Working Group for Sarcopenia. For each sex, a multiple regression analysis determined the factors that affect jaw-opening force. Jaw-opening force was associated with the cross-sectional area of the geniohyoid muscle in males (regression coefficient [β] = 0.441, 95% confidence interval [CI] = 14.28-56.09) and females (β = 0.28, 95% CI = 3.10-54.57). Furthermore, in females only, jaw-opening force was associated with the skeletal muscle mass index (β = 0.40, 95% CI = 3.67-17.81). In contrast, jaw-opening force was not associated with the cross-sectional area of the anterior belly of the digastric muscle in either sex. In healthy elderly males and females, jaw-opening force was positively associated with the cross-sectional area of the geniohyoid muscle. However, the jaw-opening force was positively associated with the skeletal muscle mass index only in females.

The mylohyoid (MH) musculature separates the sublingual and submandibular spaces and is, therefore, important with regard to the spread of infection and space occupying lesions. Moreover, the MH may be elevated and included in the myocutaneous submental island flap or sutured in conjunction with the platysmas and the anterior bellies of the digastric muscles (ABDMs) to add stability to submental muscular medialization procedures. Therefore, variation in the anatomy of the MH musculature must be considered in the management of the spread of infection and space occupying lesions as well as in surgical planning. This report reviews mylohyoid variations and documents a unique case in which several suprahyoid muscular variations occurred concurrently. The variations included isolated anterior bellies of the mylohyoid inserting into the geniohyoid thereby forming mylo-geniohyoid muscles as well as isolated posterior bellies of the mylohyoid inserting into the ABDM and the intermediate tendon of the digastric muscle thereby forming mylo-digastric muscles. Surgeons operating in the suprahyoid region should be aware of potential anatomical variation of the mylohyoid to develop contingency plans.

Epidermoid cysts, true dermoid cysts and teratoid cysts compose the spectrum of cystic teratomas, which are defined as neoplasms whose tissue are derivatives of more than one germ layer, foreign to that part of the body from which the tumor arises. Epidermoid cysts of the floor of the mouth are rare lesions and are much less common than dermoid cysts in the head and neck. This case reports a 43-year-old male patient who presented with a longstanding midline swelling in the submental region. Initial imaging was done using ultrasound followed by computed tomography (CT) scan. Biopsy was taken and revealed a cyst wall lined with epidermal squamous epithelium along with areas of focal ulceration suggesting chronic inflammatory changes of the wall of the epidermoid cyst. There are characteristic and even pathognomonic imaging features of epidermoid cysts at the floor of the mouth in ultrasound and CT scan. Imaging has an important role in the surgical management plan according to the size and location of the cyst in relation to geniohyoid and mylohyoid muscles.