The Role of Neck Muscle Co-contraction and Postural Changes in Head Kinematics after Safe Head Impacts: Investigation of Head/Neck Injury Reduction

2021 ◽  
pp. 110732
Author(s):  
Mohammad Homayounpour ◽  
Nicholas G. Gomez ◽  
Anita N. Vasavada ◽  
Andrew S. Merryweather
Keyword(s):  
Neck Injury ◽  
Neck Muscle ◽  
Head Impacts ◽  
Head Kinematics ◽  
Injury Reduction ◽  
Postural Changes ◽  
Head Neck

scholarly journals How Can We Manage Gallbladder Lesions by Transabdominal Ultrasound?

Diagnostics ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 784
Author(s):  
Shinji Okaniwa
Keyword(s):  
High Frequency ◽  
Layer Structure ◽  
Wall Layer ◽  
Pancreaticobiliary Maljunction ◽  
Doppler Imaging ◽  
Wall Thickening ◽  
Contrast Enhanced ◽  
Postural Changes ◽  
Venous Phase

The most important role of ultrasound (US) in the management of gallbladder (GB) lesions is to detect lesions earlier and differentiate them from GB carcinoma (GBC). To avoid overlooking lesions, postural changes and high-frequency transducers with magnified images should be employed. GB lesions are divided into polypoid lesions (GPLs) and wall thickening (GWT). For GPLs, classification into pedunculated and sessile types should be done first. This classification is useful not only for the differential diagnosis but also for the depth diagnosis, as pedunculated carcinomas are confined to the mucosa. Both rapid GB wall blood flow (GWBF) and the irregularity of color signal patterns on Doppler imaging, and heterogeneous enhancement in the venous phase on contrast-enhanced ultrasound (CEUS) suggest GBC. Since GWT occurs in various conditions, subdividing into diffuse and focal forms is important. Unlike diffuse GWT, focal GWT is specific for GB and has a higher incidence of GBC. The discontinuity and irregularity of the innermost hyperechoic layer and irregular or disrupted GB wall layer structure suggest GBC. Rapid GWBF is also useful for the diagnosis of wall-thickened type GBC and pancreaticobiliary maljunction. Detailed B-mode evaluation using high-frequency transducers, combined with Doppler imaging and CEUS, enables a more accurate diagnosis.

Stance- and Locomotion-Dependent Processing of Vibration-Induced Proprioceptive Inflow From Multiple Muscles in Humans

2007 ◽  
Vol 97 (1) ◽  
pp. 772-779 ◽  
Author(s):  
Grégoire Courtine ◽  
Alessandro Marco De Nunzio ◽  
Micaela Schmid ◽  
Maria Vittoria Beretta ◽  
Marco Schieppati
Keyword(s):  
Lower Limb ◽  
The Body ◽  
Whole Body ◽  
Neck Muscle ◽  
Muscle Vibration ◽  
Mapping Study ◽  
Body Mapping ◽  
Neck Muscle Vibration ◽  
Postural Changes ◽  
Postural Orientation

We performed a whole-body mapping study of the effect of unilateral muscle vibration, eliciting spindle Ia firing, on the control of standing and walking in humans. During quiet stance, vibration applied to various muscles of the trunk-neck system and of the lower limb elicited a significant tilt in whole body postural orientation. The direction of vibration-induced postural tilt was consistent with a response compensatory for the illusory lengthening of the stimulated muscles. During walking, trunk-neck muscle vibration induced ample deviations of the locomotor trajectory toward the side opposite to the stimulation site. In contrast, no significant modifications of the locomotor trajectory could be detected when vibrating various muscles of the lower as well as upper limb. The absence of correlation between the effects of muscle vibration during walking and standing dismisses the possibility that vibration-induced postural changes can account for the observed deviations of the locomotor trajectory during walking. We conclude that the dissimilar effects of trunk-neck and lower limb muscle vibration during walking and standing reflect a general sensory-motor plan, whereby muscle Ia input is processed according to both the performed task and the body segment from which the sensory inflow arises.

Postural changes after sustained neck muscle contraction in persons with a lower leg amputation

2009 ◽  
Vol 19 (4) ◽  
pp. e214-e222 ◽  
Author(s):  
Cyril Duclos ◽  
Régine Roll ◽  
Anne Kavounoudias ◽  
Jean-Philippe Mongeau ◽  
Jean-Pierre Roll ◽  
...  
Keyword(s):  
Muscle Contraction ◽  
Lower Leg ◽  
Neck Muscle ◽  
Postural Changes ◽  
Lower Leg Amputation ◽  
Leg Amputation

The Influence of Neck Stiffness on Head Kinematics and Maximum Principal Strain Associated With Youth American Football Collisions

2021 ◽  
pp. 1-8
Author(s):  
Janie Cournoyer ◽  
David Koncan ◽  
Michael D. Gilchrist ◽  
T. Blaine Hoshizaki
Keyword(s):  
American Football ◽  
Principal Strain ◽  
Neck Stiffness ◽  
Head Impacts ◽  
Head Kinematics ◽  
Upper Trapezius ◽  
Maximum Principal Strain ◽  
Direct Head ◽  
Hybrid Iii ◽  
Neck Strength

Understanding the relationship between head mass and neck stiffness during direct head impacts is especially concerning in youth sports where athletes have higher proportional head mass to neck strength. This study compared 2 neck stiffness conditions for peak linear and rotational acceleration and brain tissue deformations across 3 impact velocities, 3 impact locations, and 2 striking masses. A pendulum fitted with a nylon cap was used to impact a fifth percentile hybrid III headform equipped with 9 accelerometers and fitted with a youth American football helmet. The 2 neck stiffness conditions consisted of a neckform with and without resistance in 3 planes, representing the upper trapezius, the splenius capitis, and the sternocleidomastoid muscles. Increased neck stiffness resulted in significant changes in head kinematics and maximum principal strain specific to impact velocity, impact location, and striking mass.

The Role of the Playing Surface in Mitigating the Deleterious Effects of Head Impacts in Field Sports

2021 ◽  
pp. 119-144
Author(s):  
Breana Cappuccilli ◽  
Nicolas Leiva-Molano ◽  
Thomas M. Talavage ◽  
Eric A. Nauman
Keyword(s):  
Head Impacts ◽  
Field Sports

Effects of postural changes and vestibular lesions on diaphragm and rectus abdominis activity in awake cats

2001 ◽  
Vol 91 (1) ◽  
pp. 137-144 ◽  
Author(s):  
L. A. Cotter ◽  
H. E. Arendt ◽  
J. G. Jasko ◽  
C. Sprando ◽  
S. P. Cass ◽  
...  
Keyword(s):  
Vestibular System ◽  
Muscle Activity ◽  
Abdominal Muscle ◽  
Rectus Abdominis ◽  
Abdominal Muscles ◽  
Body Rotation ◽  
Postural Changes ◽  
Before And After ◽  
Awake Cats

Changes in posture can affect the resting length of the diaphragm, requiring alterations in the activity of both the abdominal muscles and the diaphragm to maintain stable ventilation. To determine the role of the vestibular system in regulating respiratory muscle discharges during postural changes, spontaneous diaphragm and rectus abdominis activity and modulation of the firing of these muscles during nose-up and ear-down tilt were compared before and after removal of labyrinthine inputs in awake cats. In vestibular-intact animals, nose-up and ear-down tilts from the prone position altered rectus abdominis firing, whereas the effects of body rotation on diaphragm activity were not statistically significant. After peripheral vestibular lesions, spontaneous diaphragm and rectus abdominis discharges increased significantly (by ∼170%), and augmentation of rectus abdominis activity during nose-up body rotation was diminished. However, spontaneous muscle activity and responses to tilt began to recover after a few days after the lesions, presumably because of plasticity in the central vestibular system. These data suggest that the vestibular system provides tonic inhibitory influences on rectus abdominis and the diaphragm and in addition contributes to eliciting increases in abdominal muscle activity during some changes in body orientation.

Mechanical role of expiratory muscles during breathing in upright dogs

1988 ◽  
Vol 64 (3) ◽  
pp. 1060-1067 ◽  
Author(s):  
G. A. Farkas ◽  
R. E. Baer ◽  
M. Estenne ◽  
A. De Troyer
Keyword(s):  
Tidal Volume ◽  
Progressive Increase ◽  
Substantial Contribution ◽  
Postural Changes ◽  
Before And After ◽  
Cervical Vagotomy ◽  
Anesthetized Dogs ◽  
Expiratory Muscles ◽  
Spontaneously Breathing

To examine the mechanical effects of the abdominal and triangularis sterni expiratory recruitment that occurs when anesthetized dogs are tilted head up, we measured both before and after cervical vagotomy the end-expiratory length of the costal and crural diaphragmatic segments and the end-expiratory lung volume (FRC) in eight spontaneously breathing animals during postural changes from supine (0 degree) to 80 degrees head up. Tilting the animals from 0 degree to 80 degrees head up in both conditions was associated with a gradual decrease in end-expiratory costal and crural diaphragmatic length and with a progressive increase in FRC. All these changes, however, were considerably larger (P less than 0.005 or less) postvagotomy when the expiratory muscles were no longer recruited with tilting. Alterations in the elastic properties of the lung could not account for the effects of vagotomy on the postural changes. We conclude therefore that 1) by contracting during expiration, the canine expiratory muscles minimize the shortening of the diaphragm and the increase in FRC that the action of gravity would otherwise introduce, and 2) the end-expiratory diaphragmatic length and FRC in upright dogs are thus actively determined. The present data also indicate that by relaxing at end expiration, the expiratory muscles make a substantial contribution to tidal volume in upright dogs; in the 80 degrees head-up posture, this contribution would amount to approximately 60% of tidal volume.

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