Hyoid Muscles Research Articles

Evidence based therapeutic and assessment techniques to rehabilitate post stroke dysphagia patients-A systematic review.

Dysphagia is most prevalent among post stroke aging adults. This systematic review was conducted to collect evidence-based data regarding assessment and therapeutic techniques used to rehabilitate post stroke dysphagia patients. Four major databases including PubMed, Cochrane Library, Science direct and Google scholar were searched systematically using the defined search strategy to target Randomized Controlled Trials conducted from January 2018 to 2023 using the pre-defined search strategy by three independent reviewers. After following PRISMA guidelines, fifteen articles matched the inclusion criteria. Several evidence based therapies like Neuromuscular Electrical Stimulation Therapy, Effortful Swallowing Training, Tongue Pressure Strength and Accuracy Training, Electrical Stimulation of Hyoid Muscles, Modified Chin Tuck Against Resistance exercise, Oral Neuromuscular Training, and Conventional Speech Therapy with Functional Electrical Stimulation were used frequently for the treatment of old age post stroke dysphagia in different rehabilitation centers. Along with this, a list of different assessment methodologies and tools was made that were used including Functional Oral Intake Scale, Fiber optic Endoscopic Evaluation of Swallowing, Penetration Aspiration Scale, Pooling Scale, Video fluoroscopic Dysphagia Scale, Iowa Oral Performance Instrument, Mann Assessment of Swallowing Ability, and Repetitive Saliva Swallowing Test. Dysphagia is known to be serious complication of stroke. This systematic review shows a significant impact of therapeutic techniques on post stroke dysphagia patients and demonstrates that neuromuscular electrical stimulation therapy is one of the most effective therapeutic techniques used to rehabilitate post stroke dysphagia patients.

Effect of autoantibodies and cytokines on thyroid disorders in Thi-Qar

Introduction: The thyroid gland is one of the important endocrine gland that have many functional activates in the body. It is usually located in the front of the neck and is shaped like a butterfly. It goes all the way down to the platysma, stern thyroid, and Stern hyoid muscles. In all vertebrates, the thyroid gland and its hormones perform several important activities. Methodology: Fifty patients diagnosed with hyperthyroidism disease (25 males and 25 females). 50 subjects in good health as controls (25 males and 25 females). Results and dissuasion: When compared to controls, the findings of our investigation (17.04 ± 5.10 vs. 1.15 ±0.25 U /l) demonstrate a substantial rise (P≥0.00) of TSH-receptor Ab levels in the subjects (17.04 ± 5.10 vs. 1.15 ±0.25 U/l). The findings revealed a substantial rise (P≥0.00) in FT4 level in subjects (6.16 ±0.62 vs. 1.40±0.24 ng/dl) compared to controls. In our investigation, the T3 level demonstrates a considerable rise (P≥0.00) of patients (2.81±0.20 vs. 0.32±0.07 ng/dl) vs. control. The findings of our investigation, which were presented in table 3.2, clearly demonstrated a substantial drop (P≥0.00) of TSH level in subjects was (0.19± 00.6 vs. 3.19± 0.53 IU/L) compared to controls. Conclusions: TSH-R Ab is the better hyperthyroidism marker, especially in individuals having elevated TNF plus IL-6, in both males as well as females. The close relationship among TSH-R Ab elevation, FT-4 as well as FT-3 concentration in patients having hyperthyroidisms, which is associated with increased immune response activity manifested in TNF and IL-6 accompanied by a decrease in the concentration of TSH in general comparisons and between males and females as a control group.

ANATOMICAL MODELING OF THE SUPERFICIAL MUSCLES OF NECK IN PERINATAL PERIOD OF ONTOGENESIS

The analysis of the literature indicates the high interest of not only domestic, but also foreign scientists in the anatomy and topography of the neck muscles at various stages of ontogenesis for adequate surgical correction of abnormalities in newborns and young children. The study was performed on 63 objects of human fetuses aged from 4 to 10 months and 7 newborns (in particular, 5 isolated organ complexes). For create anatomical models of the surface muscles of the neck, muscle parameters and commonly known neck sizes were determined in all age groups. The length of the muscles was determined from the place of its beginning to the place of attachment, the width – at the level of its widest part, that is, at the level of the anatomical diameter. Statistical analysis of the obtained data was performed using the licensed program RStudio. For the morphometric parameters of the sternocleidomastoid and scapulohyoid muscles during the perinatal period of development, periods of accelerated development are characteristic, for the length of the sternocleidomastoid muscle – from the 5th to the 9th month, for the length scapular- hyoid muscle – from the 4th to the 6th month of intrauterine development. For width of the right and left sternocleidomastoid muscle has two periods of the most intense increase: during 5-6 and 8-10 months of development, while the width of the right and left scapulohyoid muscle increases gradually during this period of development. The created anatomical model based on the morphometric parameters of the surface muscles of the neck is a template for all age groups during the perinatal period of ontogenesis with the aim of establishing typical and variant anatomy with the subsequent prediction of developmental abnormalities or congenital pathology. The established correlation relationships between the morphometric parameters of the sternoclavicular mastoid and scapular- hyoid muscles during the perinatal period of development testify to their synchronous and harmonious development.

The Relationship between Posture and Muscle Tensive Dysphonia in Teachers: A Systematic Scoping Review.

Teachers usually present work-related pain such as neck pain. Their posture could be the cause of these problems; indeed, it is often a sway-back posture. Furthermore, teachers can also experience problems with their voice such as dysphonia, specifically muscle tension dysphonia (MTD). This scoping review aims to find the correlation between teachers' posture and MTD. It also studies how a posture-based treatment can influence this disorder. Randomized controlled trials, controlled clinical trials, prospective cohort studies, and cross-sectional studies that considered the relationship between posture and MTD and that included teachers in their sample. The search led to an initial number of 396 articles; after the screening process, a final number of eight articles were included. A total of 303 patients were analyzed and all showed altered alignment of the head around the cervical spine with hypertonus of the cricothyroid, suprahyoid, and sternocleidomastoid muscles. Although MTD is a disorder with a multifactorial etiology, the articles revealed a correlation between posture and MTD related to a forward protraction of the cervical spine with a hypertonus of the laryngeal and hyoid musculature. This study also detected that an intervention in posture could reduce vocal disorders.

Can first cervical vertebrae misalignment be one of the possible etiology of globus pharyngeus?

Globus pharyngeus (GP) is a problem characterised by the sensation of a foreign body in the throat. Although it was previously considered as a psychological problem, it has been associated with various etiological factors such as gastrointestinal problems and cervical pathologies. The etiology and treatment of globus pharyngeus is still controversial in the literature. The hyoid muscles are innervated by the trigeminus (V), facialis (VII) and ansa cervicalis (hypoglossus (XII) and cervical spinal nerves (C1-2 nerves)). We hypothesized that C1 vertebra misalignment may cause cervical spinal nerve impingement and affect the hyoid muscles via the ansa cervicalis or the trigeminal convergence pathway in the descending pathways and cause GP. In the present case report, C1 vertebra misalignment was observed in the radiographic evaluations of a 26-year-old male patient who was admitted with the diagnosis of GB. After 5 weeks (once a week/30 min) of cervical manual physical therapy by a physiotherapist, the C1 misalignment improved, and all complaints were resolved. Based on our hypothesis, cervical misalignment should be considered as an etiological factor in patients with GP. Accordingly, cervical manual physical therapy approaches may be effective in the treatment of GP.

Assessing Swallowing Dysfunction Aggravation in Chronic Obstructive Pulmonary Disease Patients Using Ultrasonic Measurements With Swallowing Movement Parameters.

To investigate the correlation between ultrasonic measurements of swallowing movement parameters and aggravation of swallowing dysfunction in patients with chronic obstructive pulmonary disease (COPD). COPD patients with swallowing dysfunction (n = 120) and COPD patients with normal swallowing function (n = 100) treated in our hospital between January 2020 and January 2023 were included in observation and control groups, respectively. The correlation between ultrasonic measurements of swallowing movement parameters and COPD with swallowing dysfunction was analyzed. The observation group was divided into mild and severe groups according to their Gugging Swallowing Screen (GUSS) scores. The correlation between ultrasonic measurements of swallowing movement parameters and COPD exacerbation combined with swallowing dysfunction was analyzed. In the observation group, Hyoid muscle thickness, hyoid bone displacement, geniohyoid muscle movement distance, HLAS, and CSR were lower compared to the control group, negatively associated with COPD-related swallowing issues. Conversely, geniohyoid muscle movement time and minimum hyohyoid distance (NHLA) were higher in the observation group, positively correlated with COPD-related swallowing dysfunction. In COPD patients with swallowing problems, the severe group exhibited lower values for lingual muscle thickness, hyoid bone displacement, geniohyoid muscle movement distance, HLAS, and CSR compared to the mild group, while geniohyoid muscle movement time and NHLA were higher in the severe group. Receiver operating characteristic (ROC) curves were created, indicating the promising diagnostic utility of these parameters for assessing the presence and severity of swallowing dysfunction in COPD patients. The ultrasonic measurement of swallowing motion parameters can effectively assess swallowing dysfunction in COPD patients.

Tongue, palatal, hyoid and pharyngeal muscle activity during chewing, swallowing, and respiration

ObjectiveChewing, swallowing, and respiration are synchronized oropharyngeal functions. This study aimed to analyze the dynamics and coordination during natural chewing and swallowing in relation to respiratory phases. DesignEight oropharyngeal muscles in minipigs were recorded using electromyography, X-ray fluoroscopy, and nasopharyngeal dynamics. Chewing cycles and swallowing episodes were analyzed for timing and activity amplitude along respiratory cycles. Digastric and middle pharyngeal constrictor were used as zero-points for timing analysis in chewing cycles and swallowing episodes, respectively. The beginning of these cycles and episodes were used as the zero-point for timing analysis in respiration during feeding. ResultsThe timing of jaw closing (57.8%) was longer than opening (42.2%) during chewing. Muscle activity occurred 20% later than digastric onsets and 15% earlier than jaw closing phase. Duration of muscle activity was shorter in ipsilateral than contralateral sides except for palatal muscles. Pharyngeal, palatal, and hyoid muscles showed longer durations than tongue muscles in jaw opening (p < 0.05). Palatal and hyoid muscles showed 2-phased activity in chewing while hyoid muscles showed higher amplitude in chewing and swallowing than other muscles. About 80% of the chewing cycles and swallowing episodes occurred in expiration. Nasopharyngeal airflow velocity increased from jaw opening to swallowing while airflow pressure decreased. ConclusionThese findings indicate key activity of palatal and pharyngeal muscles mostly in chewing. The respiratory cycle changes in chewing and swallowing simultaneously with the activation of the tongue, palatal, and pharyngeal muscles. These findings will be useful for further understanding the mechanisms in swallowing and breathing disorders.

Use of suction electrodes for measurement of intrinsic tongue muscular endurance during lingual pressure generation.

Lingual pressure (LP) generation is cooperatively controlled not only by the intrinsic tongue (I-ton) muscles but also by hyoid muscle activation. However, the measurement of endurance and fatigue properties of I-ton muscles is difficult due to the instability of electrodes. The purpose of this study was to apply suction electrodes to measure electromyograms (EMGs) of I-ton muscle and to evaluate integrated EMG amplitude (iEMG) and mean power frequency (MPF) of EMG in the I-ton and hyoid muscles performing continuous LP. Twenty healthy adult volunteers (10 males, 10 females, mean age 28.8 years) were instructed to perform 10-s LP generation tasks at 25%, 50%, 75% and 100% of maximum LP in randomised order with visual feedback. During each task, EMGs of the I-ton, suprahyoid (S-hyo), infrahyoid (I-hyo) and masseter (Mass) muscles were simultaneously recorded. The iEMG and MPF of EMG burst during 10-s LP tasks were compared. The recording period was divided into three substages to analyse temporal changes with the Friedman test. During the 10-s task, the iEMG significantly increased as the LP strength increased (p < .001). There was no time-dependent change in the I-ton iEMG; however, the MPF of the I-ton EMG burst decreased in all tasks (p < .05). The S-hyo and I-hyo iEMGs gradually increased, especially with strong LP (p < .01). While I-ton muscles may easily fatigue during 10-s LP generation, S-hyo and I-hyo muscles may help compensate for the weakened I-ton muscle activity by increasing their activity to maintain LP.

Correction to ‘The contractile patterns, anatomy and physiology of the hyoid musculature change longitudinally through infancy’ (2022) by Mayerl et al.

Correction to ‘The contractile patterns, anatomy and physiology of the hyoid musculature change longitudinally through infancy’ (2022) by Mayerl <i>et al.</i>

Quantification of the Swallowing Mechanism Through Muscle Synergy Analysis.

Decreased swallowing function increases the risk of choking and aspiration pneumonia. Videofluoroscopy and computed tomography allow for detailed observation of the swallowing movements but have radiation risks. Therefore, we developed a method using surface electromyography (sEMG) to noninvasively assess swallowing function without radiation exposure. A 44-channel flexible sEMG sensor was used to measure the sEMG signals of the hyoid muscles during swallowing in 14 healthy young adult and 14 elderly subjects. Muscle synergy analysis was performed to extract the muscle synergies from the sEMG signals, and the three synergies were extracted from the hyoid muscle activities during the swallowing experiments. The experimental results showed that the three synergies represent the oral, early pharyngeal, and late pharyngeal swallowing phases and that swallowing strength is tuned by the strength of the muscle activities, whereas swallowing volume is controlled by adjusting muscle activation timing. In addition, the timing of the swallowing reflex is slower in elderly individuals. The results confirm that the proposed approach successfully quantifies swallowing function from sEMG signals, mapping the signals to the swallowing phases.

The anatomy of the head muscles in caecilians (Amphibia: Gymnophiona): Variation in relation to phylogeny and ecology?

In limbless fossorial vertebrates such as caecilians (Gymnophiona), head-first burrowing imposes severe constraints on the morphology and overall size of the head. As such, caecilians developed a unique jaw-closing system involving the large and well-developed m. interhyoideus posterior, which is positioned in such a way that it does not significantly increase head diameter. Caecilians also possess unique muscles among amphibians. Understanding the diversity in the architecture and size of the cranial muscles may provide insights into how a typical amphibian system was adapted for a head-first burrowing lifestyle. In this study, we use dissection and non-destructive contrast-enhanced micro-computed tomography (μCT) scanning to describe and compare the cranial musculature of 13 species of caecilians. Our results show that the general organization of the head musculature is rather constant across extant caecilians. However, the early-diverging Rhinatrema bivittatum mainly relies on the 'ancestral' amphibian jaw-closing mechanism dominated by the m. adductores mandibulae, whereas other caecilians switched to the use of the derived dual jaw-closing mechanism involving the additional recruitment of the m. interhyoideus posterior. Additionally, the aquatic Typhlonectes show a greater investment in hyoid musculature than terrestrial caecilians, which is likely related to greater demands for ventilating their large lungs, and perhaps also an increased use of suction feeding. In addition to three-dimensional interactive models, our study provides the required quantitative data to permit the generation of accurate biomechanical models allowing the testing of further functional hypotheses.

РОЛЬ ЯЗЫКА В ЭТИОПАТОГЕНЕЗЕ ДИСФУНКЦИОНАЛЬНЫХ СОСТОЯНИЙ ЗУБОЧЕЛЮСТНОЙ И ДРУГИХ ФУНКЦИОНАЛЬНЫХ СИСТЕМ ЧЕЛОВЕКА

Background. The tongue is a powerful muscular organ with a variety of functions and the ability to influence many systems of the human body, which is due to the peculiarities of its embryogenesis, the proximity of many anatomical structures, rich innervation and connection with many parts of the brain. Functional changes of the tongue muscles can be associated with various pathological conditions. Thus, systemic disorders secondarily involve the tongue, and local changes in the tongue (tongue dysfunction, tumors,changes in the mucous membrane in old age and with existing somatic diseases, obstructive sleep apnea syndrome and emotional can develop into systemic diseases. Tongue has embryological and functional relationship with the occipital region and the hyoid bone, which develop from the second gill arch. In addition, anatomically, the tongue is also interconnected with the hyoid bone and, therefore, with hyoid muscles and muscles of the mouth bottom.&#x0D; Aim. To determine the significance of the functional features of human tongue in the etiopathogenesis of dysfunctional states of the muscular, respiratory and other systems and the psycho-emotional sphere of the human body.&#x0D; Material and methods. Was analyzed the researchers results from available literature sources from the "Elibrary" and "Pubmed" platforms, including patents and scientific articles of domestic and foreign authors. &#x0D; Results. The paper presents data from literature sources on anatomical and functional relationships with human body systems. The correct physiological localization of the tongue in the oral cavity is described, the advantages of this position are given.&#x0D; Conclusions. It is well known that the tongue participates in speech formation, chewing, swallowing. However, the facts of the influence of the position and functional features of the tongue during breathing, the formation of structures of the maxillary system, the maintenance of posture and muscle balance of the human body, facial function, in the emotional sphere are interesting.

Correlation between cervical auscultation and electromyography in the pharyngeal phase of swallowing

Objective: Correlate the acoustic data of cervical auscultation to the electrical activity of the muscles involved in the pharyngeal phase of swallowing. Methods: This is an observational, cross-sectional study involving a quantitative approach and was approved on January by CEP/UFSCPA (number 1.389.050). All participants of the study signed an informed consent form. The pharyngeal phase of swallowing was assessed by employing auscultation and surface electromyography. Individuals ingested 90 ml of water. The auscultation data were transferred to DeglutiSom® software, the duration and amplitude of electromyographic activity was measured during swallowing using a Miotec® surface electromyography device. The level of significance adopted was 5%. Results: Fifty-seven women participated in this study. The average age was 23.4 years on average. It must be highlighted that the greater the average peak frequency of auscultation, lower was the average peak of the suprahyoid muscle and the greater the intensity, the greater was the peak, as well as the average of the suprahyoid peaks. It was possible to demonstrate that the peak of suprahyoid muscle activity was significantly higher than the peak of infra hyoid muscle activity for swallowing 90 ml of water. Conclusion: The acoustic swallowing parameters in healthy individuals are correlated with the electrical activity of muscles involved in the pharyngeal phase of swallowing.

Onset Timing of Hyoid Muscles Activation during Cervical Flexion Is Position-Dependent: An EMG Study.

Due to the high prevalence of neck pain, considerable attention is paid to the function of cervical flexor muscles. Although the deep and superficial cervical flexor muscles have been evaluated, the impact of hyoid muscles on cervical flexion is still not well known. We, therefore, aimed to investigate the activation of hyoid muscles during physiological cervical flexion, and to determine the impact of different starting positions on cervical flexion muscle activation. The activities of bilateral sternocleidomastoid, scalene, suprahyoid, and infrahyoid muscles were evaluated by surface electromyography (EMG) in twenty young healthy volunteers. They performed a repetitive cervical flexion-extension movement, from neutral position of the head to the maximum flexion with the same speed set at eight seconds in a cycle, in three various positions (sitting, standing, and supine). In sitting and standing positions, the group of suprahyoid muscles was activated in advance of other cervical flexor muscles despite only significant differences were found in scalene muscles, and the activation of the group of infrahyoid muscles was time-synchronous with sternocleidomastoid muscles. On the other hand, in supine position, the activation of all measured cervical flexor muscles was significantly earlier and longer than in the other two positions. This study confirmed the empirical suggestion that hyoid muscles contributed to cervical flexion, and it confirmed that muscle activation was position dependent, even if the given movement is nearly identical.

Observation on the efficacy of post-stroke dysphagia treated with He's santong acupuncture therapy through surface electromyography: a randomized controlled trial

To observe the clinical therapeutic effect on post-stroke dysphagia treated with He's santong (triple promotion) acupuncture therapy through surface electromyography (sEMG). A total of 60 patients with post-stroke dysphagia were divided into a routine treatment group and a He's santong acupuncture therapy group, using blocked randomization, 30 cases in each one. In the routine treatment group, the secondary prevention and swallowing rehabilitation training were adopted. In the He's santong acupuncture therapy group, on the base of the treatment as the routine treatment group, weitong (mild promotion, routine acupuncture at bilateral Fengchi ［GB20］, Fengfu ［GV16］, Yifeng ［TE17］, Lianquan ［CV23］, Jia-lianquan ［Extra］, Fenglong ［ST40］ and Tongli ［HT5］, needle retaining for 30 min, 5 treatments a week), wentong (warm promotion, pricking with fire needle at bilateral GB20 and CV23, twice a week) and qiangtong (strong promotion, blood-letting with three-edge needle at Jinjin ［EX-HN12］, Yuye ［EX-HN13］ and Yanhoubi ［Extra］, twice a week) treatment was added. The therapy was given consecutively for 4 weeks in each group. The score of fiberoptic endoscopic examination of swallowing (FEES) and Rosenbek-penetration-aspiration scale (PAS), the score of swallowing grading scale, the score of the modified Mann assessment of swallowing ability (MMASA) and the peak amplitude of sEMG were recorded before and after treatment in patients. Compared with before treatment, the score of FEES and PAS after treatment was decreased (P<0.05), the scores of swallowing grading scale and MMASA after treatment were increased in both routine treatment group and He's santong acupuncture therapy group (P<0.05), the peak amplitude of sEMG was increased (P<0.05) in the He's santong acupuncture therapy group and decreased (P<0.05) in the routine treatment group. Compared with the routine treatment group, the score of FEES and PAS was decreased (P<0.05), the scores of swallowing grading scale and peak amplitude of sEMG were increased in the He's santong acupuncture therapy group (P<0.05). He's santong acupuncture therapy is obviously effective on post-stroke dysphagia, which may be related to its effects in increasing the contraction of swallowing-related muscles and improving the peak amplitude of hyoid muscle group.

Real-Time Tracking of Human Neck Postures and Movements.

Improper neck postures and movements are the major causes of human neck-related musculoskeletal disorders. To monitor, quantify, analyze, and detect the movements, remote and non-invasive based methods are being developed for prevention and rehabilitation. The purpose of this research is to provide a digital platform for analyzing the impact of human neck movements on the neck musculoskeletal system. The secondary objective is to design a rehabilitation monitoring system that brings accountability in the treatment prescribed, which is shown in the use-case model. To record neck movements effectively, a Smart Neckband integrated with the Inertial Measurement Unit (IMU) was designed. The initial task was to find a suitable position to locate the sensors embedded in the Smart Neckband. IMU-based real-world kinematic data were captured from eight research subjects and were used to extract kinetic data from the OpenSim simulation platform. A Random Forest algorithm was trained using the kinetic data to predict the neck movements. The results obtained correlated with the novel idea proposed in this paper of using the hyoid muscles to accurately detect neck postures and movements. The innovative approach of integrating kinematic data and kinetic data for analyzing neck postures and movements has been successfully demonstrated through the efficient application in a rehabilitation use case with about 95% accuracy. This research study presents a robust digital platform for the integration of kinematic and kinetic data that has enabled the design of a context-aware neckband for the support in the treatment of neck musculoskeletal disorders.

Anatomical and physiological variation of the hyoid musculature during swallowing in infant pigs.

The function of a muscle is impacted by its line of action, activity timing and contractile characteristics when active, all of which have the potential to vary within a behavior. One function of the hyoid musculature is to move the hyoid bone during swallowing, yet we have little insight into how their lines of action and contractile characteristics might change during a swallow. We used an infant pig model to quantify the contractile characteristics of four hyoid muscles during a swallow using synchronized electromyography, fluoromicrometry and high-speed biplanar videofluoroscopy. We also estimated muscle line of action during a swallow using contrast-enhanced CT-scanned muscles animated to move with the hyoid bone and found that as the hyoid elevated, the line of action of the muscles attached to it became greater in depression. We also found that muscles acted eccentrically and concentrically, which was correlated with hyoid movement. This work contributes to our understanding of how the musculature powering feeding functions during swallowing.

Comparative examination of pinniped craniofacial musculature and its role in aquatic feeding.

Secondarily aquatic tetrapods have many unique morphologic adaptations for life underwater compared with their terrestrial counterparts. A key innovation during the land‐to‐water transition was feeding. Pinnipeds, a clade of air‐breathing marine carnivorans that include seals, sea lions, and walruses, have evolved multiple strategies for aquatic feeding (e.g., biting, suction feeding). Numerous studies have examined the pinniped skull and dental specializations for underwater feeding. However, data on the pinniped craniofacial musculoskeletal system and its role in aquatic feeding are rare. Therefore, the objectives of this study were to conduct a comparative analysis of pinniped craniofacial musculature and examine the function of the craniofacial musculature in facilitating different aquatic feeding strategies. We performed anatomic dissections of 35 specimens across six pinniped species. We describe 32 pinniped craniofacial muscles—including facial expression, mastication, tongue, hyoid, and soft palate muscles. Pinnipeds broadly conform to mammalian patterns of craniofacial muscle morphology. Pinnipeds also exhibit unique musculoskeletal morphologies—in muscle position, attachments, and size—that likely represent adaptations for different aquatic feeding strategies. Suction feeding specialists (bearded and northern elephant seals) have a significantly larger masseter than biters. Further, northern elephant seals have large and unique tongue and hyoid muscle morphologies compared with other pinniped species. These morphologic changes likely help generate and withstand suction pressures necessary for drawing water and prey into the mouth. In contrast, biting taxa (California sea lions, harbor, ringed, and Weddell seals) do not exhibit consistent craniofacial musculoskeletal adaptations that differentiate them from suction feeders. Generally, we discover that all pinnipeds have well‐developed and robust craniofacial musculature. Pinniped head musculature plays an important role in facilitating different aquatic feeding strategies. Together with behavioral and kinematic studies, our data suggest that pinnipeds’ robust facial morphology allows animals to switch feeding strategies depending on the environmental context—a critical skill in a heterogeneous and rapidly changing underwater habitat.

Elevated Hyoid Bone Position in Response to Mandibular Advancing Appliance Predicts Effectiveness of the Appliance for Obstructive Sleep Apnea

The objective was to determine whether hyoid bone elevation induced by an anterior mandibular positioning appliance (AMP) predicts the effectiveness of the AMP in patients with obstructive sleep apnea (OSA). Fifteen patients (12 males and 3 females) underwent polysomnographic recordings and lateral cephalograms before and after AMP use of at least 6 months. Measurements of sleep variables and upper airway morphology were compared between pre-AMP and with-AMP states. The AMP appliance reduced apnea-hypopnea indices (AHI) ~53% (33.77 ± 3.29 vs. 15.85 ± 3.78, P = 0.0013). Cephalograms of the oropharyngeal airway showed that the hyoid bone moved superiorly toward the inferior mandibular border (Δ H-MP) ~5 mm (23.4 ± 1.44 vs. 18.27 ± 1.86, P = 0.0377), with the AMP inserted in the oral cavity; no airway measurement other than hyoid bone position changed. No significant correlations emerged between AHI improvement (Δ AHI) and amounts of hyoid elevation (Δ H-MP) when all patients were pooled. However, when the samples were subcategorized, the correlation coefficients increased significantly (P &amp;lt; 0.01) in both subgroups. This outcome suggests the presence of two distinct types among the “Good-Responders” to AMP appliance use. Overall use of the AMP appliance is effective; however, the effectiveness of the appliance appears to depend on the mode of hyoid elevations, likely resulting from muscle responsiveness in patients with AMP use. The results suggest that Δ H-MP measurements may be a useful marker to segregate patients with tongue and hyoid muscles responsive to AMP from those not-so-responsive.

The contractile patterns, anatomy and physiology of the hyoid musculature change longitudinally through infancy.

All mammalian infants suckle, a fundamentally different process than drinking in adults. Infant mammal oropharyngeal anatomy is also anteroposteriorly compressed and becomes more elongate postnatally. While suckling and drinking require different patterns of muscle use and kinematics, little insight exists into how the neuromotor and anatomical systems change through the time that infants suckle. We measured the orientation, activity and contractile patterns of five muscles active during infant feeding from early infancy until weaning using a pig model. Muscles not aligned with the long axis of the body became less mediolaterally orientated with age. However, the timing of activation and the contractile patterns of those muscles exhibited little change, although variation was larger in younger infants than older infants. At both ages, there were differences in contractile patterns within muscles active during both sucking and swallowing, as well as variation among muscles during swallowing. The changes in anatomy, coupled with less variation closer to weaning and little change in muscle firing and shortening patterns suggest that the neuromotor system may be optimized to transition to solid foods. The lesser consequences of aspiration during feeding on an all-liquid diet may not necessitate the evolution of variation in neuromotor function through infancy.