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1.
Sensors (Basel) ; 24(5)2024 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-38474961

RESUMO

This study investigated the impact of auditory stimuli on muscular activation patterns using wearable surface electromyography (EMG) sensors. Employing four key muscles (Sternocleidomastoid Muscle (SCM), Cervical Erector Muscle (CEM), Quadricep Muscles (QMs), and Tibialis Muscle (TM)) and time domain features, we differentiated the effects of four interventions: silence, music, positive reinforcement, and negative reinforcement. The results demonstrated distinct muscle responses to the interventions, with the SCM and CEM being the most sensitive to changes and the TM being the most active and stimulus dependent. Post hoc analyses revealed significant intervention-specific activations in the CEM and TM for specific time points and intervention pairs, suggesting dynamic modulation and time-dependent integration. Multi-feature analysis identified both statistical and Hjorth features as potent discriminators, reflecting diverse adaptations in muscle recruitment, activation intensity, control, and signal dynamics. These features hold promise as potential biomarkers for monitoring muscle function in various clinical and research applications. Finally, muscle-specific Random Forest classification achieved the highest accuracy and Area Under the ROC Curve for the TM, indicating its potential for differentiating interventions with high precision. This study paves the way for personalized neuroadaptive interventions in rehabilitation, sports science, ergonomics, and healthcare by exploiting the diverse and dynamic landscape of muscle responses to auditory stimuli.


Assuntos
Contração Muscular , Dispositivos Eletrônicos Vestíveis , Contração Muscular/fisiologia , Intervenção Psicossocial , Eletromiografia , Músculos do Pescoço/fisiologia
2.
Sci Rep ; 14(1): 5844, 2024 03 10.
Artigo em Inglês | MEDLINE | ID: mdl-38462647

RESUMO

The lesser occipital nerve (LON) has one of the most variations among occipital nerves. We aimed to investigate morphological and morphometric features of LON. A total of 24 cadavers, 14 males (58%) and 10 females (42%), were dissected bilaterally. LON was classified into 3 types. The number of branches and the perpendicular distances of the point where LON emerged from the posterior border of sternocleidomastoid muscle to vertical and transverse lines passing through external occipital protuberance were determined. The shortest distance between LON and great auricular nerve (GAN), and linear distance of LON to its branching point were measured. The most common variant was Type 1 (30 sides, 62.5%), followed by Type 2 (12 sides, 25%) and Type 3 (6 sides, 12.5%), respectively. In males, Type 1 (22 sides, 78.6%) was the most common, while Type 1 (8 sides, 40%) and Type 2 (8 sides, 40%) were equally common and the most common in females. On 48 sides, 2-9 branches of LON were observed. The perpendicular distance of said point to vertical and transverse lines was meanly 63.69 ± 11.28 mm and 78.83 ± 17.21 mm, respectively. The shortest distance between LON and GAN was meanly 16.62 ± 10.59 mm. The linear distance of LON to its branching point was meanly 31.24 ± 15.95 mm. The findings reported in this paper may help clinicians in estimating the location of the nerve and/or its branches for block or decompression surgery as well as preservation of LON during related procedures.


Assuntos
Relevância Clínica , Nervos Periféricos , Masculino , Feminino , Humanos , Nervos Periféricos/anatomia & histologia , Osso Occipital/anatomia & histologia , Músculos do Pescoço , Cadáver
5.
J Morphol ; 285(3): e21684, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38439588

RESUMO

Among marsupials, the endangered numbat (Myrmecobius fasciatus) is the only obligate myrmecophage with a diet comprised strictly of termites. Like many other specialised myrmecophagous mammals, numbats have a gracile and highly specialised skull morphology with an elongated rostrum and small braincase. Myrmecobiidae is one of four taxonomic families within the Australasian marsupial order Dasyuromorphia, and to date, the muscular anatomy of any member of this group is relatively poorly known. We utilised microdissection and contrast-enhanced microcomputed tomography scanning to provide the first comprehensive qualitative and quantitative descriptions of jaw muscle anatomy in numbats and quolls (Dasuyrus species). The arrangement of the jaw muscles across these species was conservative, both in gross anatomy and muscle proportions, corresponding to a 'generalised' mammalian pattern. In contrast to Dasyurus, the jaw muscles of the numbat were greatly reduced. Many aspects of the muscle anatomy of the numbat were similar to patterns reported in other myrmecophagous species, particularly a greatly reduced temporalis muscle. Unusually, the digastric muscle in the numbat was comprised of a single, large anterior belly while the posterior belly was absent. We propose that the enlarged anterior belly of the digastric may be linked to jaw stabilisation and coordination of tongue movements during feeding. The lateral insertion and fascial connection of the digastric to the tongue in numbats may also aid in distributing stress evenly across the jaw and minimise muscle fatigue. The muscle descriptions and three-dimensional models provided in this study will facilitate further analysis of musculoskeletal adaptation and evolution within the Dasyuromorphia.


Assuntos
Isópteros , Marsupiais , Humanos , Animais , Microtomografia por Raio-X , Músculos do Pescoço , Crânio
6.
PeerJ ; 12: e17056, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38436036

RESUMO

Balance involves several sensory modalities including vision, proprioception and the vestibular system. This study aims to investigate vestibulospinal activation elicited by tone burst stimulation in various muscles and how head position influences these responses. We recorded electromyogram (EMG) responses in different muscles (sternocleidomastoid-SCM, cervical erector spinae-ES-C, lumbar erector spinae-ES-L, gastrocnemius-G, and tibialis anterior-TA) of healthy participants using tone burst stimulation applied to the vestibular system. We also evaluated how head position affected the responses. Tone burst stimulation elicited reproducible vestibulospinal reflexes in the SCM and ES-C muscles, while responses in the distal muscles (ES-L, G, and TA) were less consistent among participants. The magnitude and polarity of the responses were influenced by the head position relative to the cervical spine. When the head was rotated or tilted, the polarity of the vestibulospinal responses changed, indicating the integration of vestibular and proprioceptive inputs in generating these reflexes. Overall, our study provides valuable insights into the complexity of vestibulospinal reflexes and their modulation by head position. However, the high variability in responses in some muscles limits their clinical application. These findings may have implications for future research in understanding vestibular function and its role in posture and movement control.


Assuntos
Orientação Espacial , Vestíbulo do Labirinto , Humanos , Percepção Espacial , Vértebras Cervicais , Cafeína , Músculos do Pescoço , Niacinamida
7.
J Bodyw Mov Ther ; 37: 399-403, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38432836

RESUMO

BACKGROUND: Ultrasonography (US) has been suggested to assess the morphology and function of cervical muscles; but little is known about the reliability of the US measures in patients with cervical disc herniation (CDH). The purpose of this study was to evaluate within-day inter and intra-rater and between-day intra-rater reliability of US to measure dimensions of deep cervical muscles in patients with unilateral CDH. METHODS: Thirty patients with unilateral CDH participated. Anterior-posterior and lateral dimension of longus colli (LC), multifidus (MF) and semispinalis cervicis (SC) were measured using B-mode ultrasound. The measurements were repeated by rater A 1 h (for within-day reliability) and one week (for between-day reliability) later. For inter-rater reliability, rater B performed all muscles measurements like rater A. RESULTS: Within-day reliability measurement for all muscles was good to excellent with IntraClass Correlation Coefficients (ICC) ranging from 0.82 to 0.96, standard error of measurement (SEM) from 0.18 to 0.46 and minimal detectable changes (MDC) from 0.43 to 1.09. Between-day reliability was good for all muscle dimensions with ICC ranging from 0.75 to 0.89, SEM from 0.30 to 0.64 and MDC from 0.71 to 1.52. Inter-rater reliability was also good with ICC ranging from 0.75 to 0.89, SEM from 0.34 to 0.65 and MDC from 0.81 to 1.55. CONCLUSIONS: US was demonstrated to have high within-day inter and intra-rater and between-day intra-rater reliability to measure muscles dimensions in patients with unilateral CDH. It can be used to assess deep cervical muscles or to monitor the effects of interventions.


Assuntos
Deslocamento do Disco Intervertebral , Músculos Paraespinais , Humanos , Músculos Paraespinais/diagnóstico por imagem , Estudos Transversais , Deslocamento do Disco Intervertebral/diagnóstico por imagem , Reprodutibilidade dos Testes , Músculos do Pescoço/diagnóstico por imagem , Ultrassonografia
8.
BMJ Case Rep ; 17(2)2024 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-38355210

RESUMO

An elderly gentleman self-presented to A+E with a 7-day history of significant and progressive left-sided neck pain, swelling and fevers, despite oral antibiotics from his general practitioner. Examination revealed a large left-sided neck mass involving levels 2-5 of the neck that was firm to palpate, with erythematous overlying skin.An urgent CT scan demonstrated a large collection throughout the length of the left sternocleidomastoid muscle (SCM), measuring 13×5.5×4 cm, with extensive adjacent inflammatory change. He was subsequently taken to theatre for washout and debridement, during which the collection was found to be loculated and isolated to the SCM, with surrounding structures spared.Postoperatively, he was managed with intravenous fluids and a total of 2 weeks of intravenous antibiotics. The wound partially dehisced during healing and the cavity was packed with flaminal and regularly dressed with input from the tissue viability team. This was then left to heal by secondary intention and the patient was followed up in clinic over the following weeks to ensure resolution.


Assuntos
Piomiosite , Sepse , Masculino , Humanos , Idoso , Piomiosite/diagnóstico , Piomiosite/tratamento farmacológico , Pescoço/diagnóstico por imagem , Músculos do Pescoço/diagnóstico por imagem , Sepse/tratamento farmacológico , Antibacterianos/uso terapêutico
9.
J Speech Lang Hear Res ; 67(3): 740-752, 2024 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-38315579

RESUMO

PURPOSE: This study set out to investigate whether individuals with dysphonia, as determined by either self-assessment or clinician-based auditory-perceptual judgment, exhibited differences in perilaryngeal muscle activities using surface electromyography (sEMG) during various phonatory tasks. Additionally, the study aimed to assess the effectiveness of sEMG in identifying dysphonic cases. METHOD: A total of 77 adults (44 women, 33 men, Mage = 30.4 years) participated in this study, with dysphonic cases identified separately using either a 10-item Voice Handicap Index (VHI-10) or clinician-based auditory-perceptual voice quality (APVQ) evaluation. sEMG activities were measured from the areas of suprahyoid and sternocleidomastoid muscles during prolonged vowel /i/ phonations at different pitch and loudness levels. Normalized root-mean-square value against the maximal voluntary contraction (RMS %MVC) of the sEMG signals was obtained for each phonation and compared between subject groups and across phonatory tasks. Additionally, binary logistic regression analysis was performed to determine how the sEMG measures could predict the VHI-10-based or APVQ-based dysphonic cases. RESULTS: Participants who scored above the criteria on either the VHI-10 (n = 29) or APVQ judgment (n = 17) exhibited significantly higher RMS %MVC in the right suprahyoid muscles compared to the corresponding control groups. Although the RMS %MVC value from the right suprahyoid muscles alone was not a significant predictor of self-evaluated dysphonic cases, a combination of the RMS %MVC values from both the right and left suprahyoid muscles significantly predicted APVQ-based dysphonic cases with a 69.66% fair level. CONCLUSIONS: This study found that individuals with dysphonia, as determined by either self-assessment or APVQ judgment, displayed more imbalanced suprahyoid muscle activities in voice production compared to nondysphonic groups. The combination of the sEMG measures from both left and right suprahyoid muscles showed potential as a predictor of dysphonia with a fair level of confidence. SUPPLEMENTAL MATERIAL: https://doi.org/10.23641/asha.25112804.


Assuntos
Disfonia , Adulto , Masculino , Humanos , Feminino , Disfonia/diagnóstico , Músculos do Pescoço , Fonação , Qualidade da Voz , Eletromiografia
11.
Asian J Surg ; 47(4): 1734-1739, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38185563

RESUMO

OBJECTIVE: This study compares endoscopic thyroidectomy by gasless unilateral axillary approach (ETGUA) and sternocleidomastoid leading-edge approach (SLEA) with conventional open thyroidectomy (COT) in hemithyroidectomy. The main focus is on the protection of neck muscles (sternocleidomastoid, omohyoid, sternothyroid) and the postoperative function of voice and swallowing yielded through these common approaches. METHODS: A total of 302 patients who underwent hemithyroidectomy were enrolled and divided into three groups: ETGUA (n = 101), SLEA (n = 100), and COT (n = 101). Ultrasound was used to measure the thickness of bilateral neck muscles, including the sternocleidomastoid, omohyoid, and sternothyroid. The changes in thickness on the surgical side compared to the non-surgical side. Analyzed factors included muscle thickness changes, Swallowing Impairment Score (SIS), Voice Handicap Index (VHI), Scar Cosmesis Assessment and Rating (SCAR), Neck Injury Index (NII), surgery duration, drainage volume, hospitalization, and number of lymph nodes. RESULTS: The clinical characteristics among the three groups were consistent except for differences in sex, age, and BMI. Metrics such as sternocleidomastoid muscle, NII, hypocalcemia, postoperative PTH, transient hoarseness, and number of lymph nodes showed no significant differences among the three groups. However, significant differences were found in the duration of surgery, drainage volume, hospitalization period omohyoid muscle, Sternohyoid muscle, VHI, SIS, and SCAR (all p < 0.001). CONCLUSION: In comparison to COT, ETGUA and SLEA demonstrate superiority in protecting neck muscles and preserving voice and swallowing function without compromising surgical safety or radicality.


Assuntos
Neoplasias da Glândula Tireoide , Tireoidectomia , Humanos , Deglutição , Músculos do Pescoço/patologia , Endoscopia , Esvaziamento Cervical , Neoplasias da Glândula Tireoide/cirurgia
12.
Surg Radiol Anat ; 46(2): 125-135, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38194160

RESUMO

Cerebrospinal fluid (CSF) circulation is considered the third circulation of the human body. Recently, some scholars have proposed the myodural bridge (MDB) as a novel power source for CSF flow. Moreover, the suboccipital muscles can exert a driving force on the CSF via the MDB. This hypothesis is directly supported by head rotation and nodding movements, which can affect CSF circulation. The MDB has been validated as a normal structure in humans and mammals. In addition, the fusion of MDB fibers of different origins that act in concert with each other forms the MDB complex (MDBC). The MDBC may be associated with several CSF disorder-related neurological disorders in clinical practice. Therefore, the morphology of the MDBC and its influencing factors must be determined. In this study, T2-weighted imaging sagittal images of the cervical region were analyzed retrospectively in 1085 patients, and magnetic resonance imaging (MRI) typing of the MDBC was performed according to the imaging features of the MDBC in the posterior atlanto-occipital interspace (PAOiS) and posterior atlanto-axial interspace (PAAiS). The effects of age and age-related degenerative changes in the cervical spine on MRI staging of the MDBC were also determined. The results revealed four MRI types of the MDBC: type A (no MDBC hyposignal shadow connected to the dura mater in either the PAOiS or PAAiS), type B (MDBC hyposignal shadow connected to the dura mater in the PAOiS only), type C (MDBC hyposignal shadow connected to the dura mater in the PAAiS only), and type D (MDBC hyposignal shadow connected to the dura mater in both the PAOiS and PAAiS). The influencing factors for the MDBC typing were age (group), degree of intervertebral space stenosis, dorsal osteophytosis, and degenerative changes in the cervical spine (P < 0.05). With increasing age (10-year interval), the incidence of type B MDBC markedly decreased, whereas that of type A MDBC increased considerably. With the deepening of the degree of intervertebral space stenosis, the incidence of type C MDBC increased significantly, whereas that of type A MDBC decreased. In the presence of dorsal osteophytosis, the incidence of type C and D MDBCs significantly decreased, whereas that of type A increased. In the presence of protrusion of the intervertebral disc, the incidence of type B, C, and D MDBCs increased markedly, whereas that of type A MDBC decreased considerably, with cervical degenerative changes combined with spinal canal stenosis. Moreover, the incidence of both type C and D MDBCs increased, whereas that of type A MDBC decreased. Based on the MRI signal characteristics of the dural side of the MDBC, four types of the MDBC were identified. MDBC typing varies dynamically according to population distribution, depending on age and cervical degeneration (degree of intervertebral space stenosis, vertebral dorsal osteophytosis formation, simple protrusion of intervertebral disc, and cervical degeneration changes combined with spinal canal stenosis, except for the degree of protrusion of the intervertebral disc and the degree of spinal canal stenosis); however, it is not influenced by sex.


Assuntos
Músculos do Pescoço , Pescoço , Animais , Humanos , Constrição Patológica , Estudos Retrospectivos , Pescoço/anatomia & histologia , Músculos do Pescoço/anatomia & histologia , Vértebras Cervicais/anatomia & histologia , Dura-Máter/anatomia & histologia , Imageamento por Ressonância Magnética , Mamíferos
13.
Appl Ergon ; 117: 104227, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38290318

RESUMO

Increasing chair recline during seated computer work may reduce the load placed on the upper trapezius (UT), a common location of pain for those with idiopathic chronic neck pain. This study determined the effect of increasing chair recline on UT stiffness and muscle activity during computer work in people with and without idiopathic chronic neck pain. Surface electromyography and ultrasound shear wave elastography were collected from three subdivisions of the UT in 15 individuals with idiopathic chronic neck pain and 15 sex-matched healthy controls. Participants sat in a standardized computer-work setup while chair recline (0°, 25°, 45°) and head and neck position (self-selected, neutral, flexed) were systematically adjusted and maintained for 2.5-min intervals. Repeated-measures ANOVAs were completed for each sex, muscle, and data type, with group (chronic neck pain, control), chair recline (0°,25°,45°), head and neck position (self-selected, flexed, neutral), and side of collected data (dominant, non-dominant) as fixed factors. Men with idiopathic chronic neck pain demonstrated greater UT stiffness in the cranial subdivision when compared to healthy men. Additionally, the 25° and 45° recline levels increased the stiffness of men's dominant UT compared to men's non-dominant UT. Women's UT was more affected by head and neck position, and a neutral head and neck position resulted in lower UT activation, but higher UT stiffness for the cranial subdivision and midway between C-7 and the acromion process. Overall, our findings suggest that the commonly suggested neutral position may not be a beneficial prompt when positioning someone during seated computer work.


Assuntos
Cervicalgia , Músculos Superficiais do Dorso , Masculino , Humanos , Feminino , Postura Sentada , Cabeça , Eletromiografia/métodos , Músculos do Pescoço/fisiologia
14.
J Oral Rehabil ; 51(5): 870-878, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38214198

RESUMO

OBJECTIVE: The purpose of this study was to clarify, using ultrasound imaging, (1) whether the area and contraction of GH change in elderly patients after hip fracture surgery and (2) whether the changes in the area and contraction of GH are related to decline in swallowing function. METHODS: The participants were 21 female patients over 65 years of age who underwent hip fracture surgery. The patients were divided into two groups based on the results of swallowing assessment by water drinking: One with normal swallowing function (NSF) and the other with suspected decline in swallowing function (DSF). Sagittal cross-sectional area (SA) of GH at rest and the shortening rate (SR) of GH upon contraction during swallowing were compared at two time points: immediately and 2 weeks after surgery. Wilcoxon signed-rank test was used for intra-group comparisons, and Mann-Whitney U-test was used for between-group comparisons. RESULT: SA of GH decreased significantly at 2 weeks after surgery in both groups, regardless of their swallowing function. In the intra-group comparison, SR significantly decreased (worsened) only in DSF group. SR at 2 weeks after surgery was significantly higher in NSF than in the DSF. In the inter-group comparison, DSF showed a significantly smaller (worse) change of SR than NSF in 2 weeks after surgery. CONCLUSION: Decrease in muscle mass, or atrophy, of GH observed in both NSF and DSF, did not coincide with the post-operative change in GH contraction of the two groups. The results suggest the importance of continuous swallowing assessment in the elderly individuals during their perioperative period.


Assuntos
Deglutição , Músculos do Pescoço , Humanos , Feminino , Idoso , Deglutição/fisiologia , Músculos do Pescoço/diagnóstico por imagem , Ultrassonografia/métodos
15.
J Indian Prosthodont Soc ; 24(1): 76-81, 2024 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-38263561

RESUMO

AIM: Occlusal splint treatment is commonly used to treat a variety of temporomandibular disorders (TMDs), with efficacy ranging between 70% and 90%. Centric splints are effective in relieving muscular soreness in individuals with TMD. Electromyography (EMG) quantifies muscle activity and can be used as an accessory diagnostic tool to evaluate the efficiency of the splint on the masticatory complex. Electromyography is used for assessing patients with TMD and observing muscle electromyography. TMD patients have altered electromyographic (EMG) masticatory muscle activity because of its change in electrical activity index or because of the compensatory mechanism for the disorder. Therefore, this study serves to evaluate the efficacy of the centric stabilization splint on TMD using EMG. SETTINGS AND DESIGN: This cross-sectional study enrolled Ten TMD Patients with TMD, who underwent treatment with centric stabilization splint. MATERIALS AND METHODS: The study involved ten young adults with TMD aged 18-45 years who were recruited without regard to sex, religion, caste, or socioeconomic background. The participants were randomized to receive a flat-contact upper stabilization splint and pregelled EMG electrodes to assess the immediate impact of centric splints on TMDs. After 3 months of follow-up, muscle activity and muscle symmetrical activity were measured to assess improvement in the symptoms of TMD. STATISTICAL ANALYSIS USED: The Shapiro-Wilk test was used to assess the normality of the variables' distribution using SPSS 26.0. Symmetrical activity and treatment response were investigated using the Wilcoxon signed-rank test. RESULTS: It showed an improvement in the temporalis, masseter, and sternocleidomastoid muscles' resting EMG activity. A statistically significant improvement was seen in the EMG activity of the bilateral temporalis, right masseter, right sternocleidomastoid, and left digastric muscles while clenching. The masseter, sternocleidomastoid, and digastric muscles all displayed significantly enhanced symmetrical activity (P < 0.05). CONCLUSIONS: This research concludes that a centric stabilizing splint assists in relieving TMD symptoms. There was enhanced masticatory muscle activity both at rest and during function. Furthermore, there was an improvement in symmetrical activity of the masticatory muscles, which improved balance and enhanced the effective functioning of the masticatory complex.


Assuntos
Transtornos da Articulação Temporomandibular , Adolescente , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem , Estudos Transversais , Músculos da Mastigação , Músculos do Pescoço , Contenções
16.
Sci Rep ; 14(1): 38, 2024 01 02.
Artigo em Inglês | MEDLINE | ID: mdl-38168918

RESUMO

Emergency braking can generate forward displacement that may influence the effectiveness of protection in collisions, especially for passengers. The development of automated vehicles has enabled the diversification and rationalization of sitting positions, including reclined seating. However, the passenger response in pre-crash scenarios in reclined seating differs from that in standard seating, which poses different requirements for biofidelic human body models (HBMs) to evaluate passenger injuries in collisions. This study conducted emergency braking trials in vehicles at an initial velocity of 80 km/h. Five volunteers were exposed to approximately 1 g manual emergency braking (MEB), and the muscle responses at the front passenger seat with backrest angles of 25°, 45°, and 65° were recorded. The electromyography obtained from 14 muscles of the neck, torso, and lower extremity were normalized using maximum voluntary contractions (MVCs). In the quiet sitting phase, the activity levels were low (< 5% MVC) in all muscles for the three sitting positions. During emergency braking, the muscles are activated to restrict the body motion. There were differences in muscle amplitude and onset time in different backrest angles, with higher muscle activity levels in most muscles in a reclined sitting position. In particular, the sternocleidomastoid, rectus abdominis, and vastus medialis showed different patterns in the peak and steady-state phases. We found that the tibialis anterior was consistently activated at a lower level in all sitting postures (< 8% MVC), which indicates limited support of the shank for the body. The data provided in the paper are presented in corridors and intended for use in the development and validation of HBMs with active muscle models to simulate evasive maneuvers that potentially occur before a crash in the reclined sitting position.


Assuntos
Acidentes de Trânsito , Músculo Esquelético , Humanos , Acidentes de Trânsito/prevenção & controle , Músculo Esquelético/fisiologia , Eletromiografia , Músculos do Pescoço , Pescoço , Fenômenos Biomecânicos
17.
Plast Reconstr Surg ; 153(3): 601-607, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-37171263

RESUMO

BACKGROUND: The platysma muscle's role in lower face dynamics is complex. Multiple insertion points to soft-tissue structures at various levels in the lower face create a multifaceted contraction pattern. To avoid adverse effects in cosmetic procedures when targeting the platysma, its anatomy and physiology must be understood. Clinical observations hint at a bidirectional contraction pattern. METHODS: Eighteen healthy volunteers (13 women and five men) with a mean age of 44.2 ± 10.1 years were enrolled. Skin displacement vector analysis was used on maximal platysma contraction to characterize and calculate the movement of the neck and lower face skin. RESULTS: In all of the participants, a bidirectional movement of the skin was observed: the skin of the lower face and inferior to the jawline moved caudally, whereas the skin of the lower neck moved cephalad. Both movements converged at a line situated at 54% ± 10% and 55% ± 8% of the length between the clavicle and the inferior base of the ear lobe in men and women, respectively ( P = 0.70). CONCLUSIONS: The platysma is a bidirectional muscle with a line of convergence. Whereas the superior portion acts as lip depressor, the lower portion elevates the skin of the upper chest and lower neck. This transition can explain some of the clinically observed adverse effects of neuromodulation of the neck area. It can potentially direct neuromodulation injections to focus above the convergence line to better address lower face descent.


Assuntos
Sistema Musculoaponeurótico Superficial , Adulto , Masculino , Humanos , Feminino , Pessoa de Meia-Idade , Sistema Musculoaponeurótico Superficial/anatomia & histologia , Pescoço , Face , Músculos do Pescoço , Pele
18.
J Oral Rehabil ; 51(3): 566-573, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37902163

RESUMO

BACKGROUND: 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. OBJECTIVE: 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. METHODS: 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. RESULTS: 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). CONCLUSION: 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.


Assuntos
Músculos Faciais , Língua , Masculino , Adulto , Feminino , Humanos , Sucção , Músculo Masseter , Músculos do Pescoço , Eletromiografia , Contração Muscular
19.
Morphologie ; 108(360): 100716, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37890282

RESUMO

Muscular variations within the upper extremities are common and widely documented. They can have a range of implications including nerve compression and misdiagnosis but are often silent. Our report herein describes a bilateral accessory muscle found in the forearm during routine cadaveric dissection. The muscle originates from the medial epicondyle of the humerus between the origins of the flexor digitorum superficialis and flexor carpi radialis muscles. The muscle is digastric, with the distal belly existing as the first lumbrical and the proximal serving as a supernumerary flexor. This functionally atavistic variation could prove clinically relevant for the purposes of donor muscle or tendon tissue as well as surgical complications and compressive neuropathies.


Assuntos
Músculo Esquelético , Tendões , Humanos , Tendões/diagnóstico por imagem , Músculos do Pescoço , Extremidade Superior , Antebraço
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