The Effect of Compression Applied Through Constrained Lateral Eccentricity on the Failure Mechanics and Flexibility of the Human Cervical Spine

2020 ◽  
Author(s):  
Angela Melnyk ◽  
Tom Whyte ◽  
Vanessa Thomson ◽  
Travis Marion ◽  
Shun Yamamoto ◽  
...  
Keyword(s):  
Cervical Spine ◽  
Axial Compression ◽  
Vertebral Body ◽  
Sagittal Plane ◽  
Lateral Force ◽  
Spine Biomechanics ◽  
High Eccentricity ◽  
Asymmetric Pattern ◽  
Before And After ◽  
Bony Injury

Abstract In contrast to sagittal plane spine biomechanics, little is known about the response of the cervical spine to axial compression with lateral eccentricity of the applied force. This study evaluated the effect of lateral eccentricity on kinetics, kinematics, canal occlusion, injuries and flexibility of the cervical spine in translationally-constrained axial impacts. Eighteen functional spinal units were subjected to flexibility tests before and after an impact. Impact axial compression was applied at one of three lateral eccentricity levels based on percentage of vertebral body width (low = 5%, medium = 50%, high = 150%). Injuries were graded by dissection. Correlations between intrinsic specimen properties and injury scores were examined for each eccentricity group. Low lateral force eccentricity produced predominantly bone injuries, clinically recognised as compression injuries, while medium and high eccentricity produced mostly contralateral ligament and/or disc injuries, an asymmetric pattern typical of lateral loading. Mean compression force at injury decreased with increasing lateral eccentricity (low = 3098 N, medium = 2337 N and high = 683 N). Mean ipsilateral bending moments at injury were higher at medium (28.3 Nm) and high (22.9 Nm) eccentricity compared to low eccentricity specimens (0.1 Nm), p<0.05. Ipsilateral bony injury was related to vertebral body area (r = -0.974, p = 0.001) and disc degeneration (r = 0.851, p = 0.032) at medium eccentricity. Facet degeneration was correlated with central bony injury at high eccentricity (r = 0.834, p = 0.036). These results deepen cervical spine biomechanics knowledge in circumstances with coronal plane loads.

scholarly journals Effects of occipital-atlas stabilization in the upper cervical spine kinematics: an in vitro study

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
César Hidalgo-García ◽  
Ana I. Lorente ◽  
Carlos López-de-Celis ◽  
Orosia Lucha-López ◽  
Miguel Malo-Urriés ◽  
...  
Keyword(s):  
Cervical Spine ◽  
Sagittal Plane ◽  
Frontal Plane ◽  
In Vitro Study ◽  
Upper Cervical Spine ◽  
Lateral Flexion ◽  
Alar Ligament ◽  
Before And After ◽  
Upper Cervical

AbstractThis study compares upper cervical spine range of motion (ROM) in the three cardinal planes before and after occiput-atlas (C0–C1) stabilization. After the dissection of the superficial structures to the alar ligament and the fixation of C2, ten cryopreserved upper cervical columns were manually mobilized in the three cardinal planes of movement without and with a screw stabilization of C0–C1. Upper cervical ROM and mobilization force were measured using the Vicon motion capture system and a load cell respectively. The ROM without C0–C1 stabilization was 19.8° ± 5.2° in flexion and 14.3° ± 7.7° in extension. With stabilization, the ROM was 11.5° ± 4.3° and 6.6° ± 3.5°, respectively. The ROM without C0–C1 stabilization was 4.7° ± 2.3° in right lateral flexion and 5.6° ± 3.2° in left lateral flexion. With stabilization, the ROM was 2.3° ± 1.4° and 2.3° ± 1.2°, respectively. The ROM without C0–C1 stabilization was 33.9° ± 6.7° in right rotation and 28.0° ± 6.9° in left rotation. With stabilization, the ROM was 28.5° ± 7.0° and 23.7° ± 8.5° respectively. Stabilization of C0–C1 reduced the upper cervical ROM by 46.9% in the sagittal plane, 55.3% in the frontal plane, and 15.6% in the transverse plane. Also, the resistance to movement during upper cervical mobilization increased following C0–C1 stabilization.

Body balance in a free-standing position in road and off-road cyclists

2014 ◽  
Vol 6 (4) ◽  
Author(s):  
Paulina Hebisz ◽  
Rafal Hebisz ◽  
Marek Zaton
Keyword(s):  
Sagittal Plane ◽  
Standing Position ◽  
The Body ◽  
Free Standing ◽  
Body Balance ◽  
Eyes Closed ◽  
Road Cycling ◽  
Progressive Exercise ◽  
Before And After ◽  
Road Cyclists

AbstractBackground: The purpose of this study was to compare body balance in road and off-road cyclists, immediately before and after the racing season.Material/Methods: Twenty individuals participated in the study and they were divided into two groups: specialists in road-cycling (n = 10) and in off-road cycling (n = 10). Immediately before and after the five-month racing season stabilographic trials were carried out (at rest and after progressive exercise). In assessing body balance the distance and velocity of the centre shifts (in the anterior-posterior and left-right direction) were analysed. The tests were performed with the cyclists’ eyes open, eyes closed, and in feedback.Results: After the racing season, in the off-road cyclists’ group, distance and velocity of the centre of pressure shifts increased after a progressive exercise.Conclusions: In the off-road cyclists’ group the balance of the body in the sagittal plane deteriorated after the racing season. Moreover, after the racing season off-road cyclists were characterized by a worse balance of the body, compared to road cyclists

Immediate effects of static and proprioceptive neuromuscular facilitation stretching of hamstring muscles on straight leg raise, craniovertebral angle, and cervical spine range of motion in neck pain patients with hamstring tightness: A prospective randomized controlled trial

2021 ◽  
pp. 1-10
Author(s):  
Eun-Dong Jeong ◽  
Chang-Yong Kim ◽  
Nack-Hwan Kim ◽  
Hyeong-Dong Kim
Keyword(s):  
Cervical Spine ◽  
Neck Pain ◽  
Range Of Motion ◽  
T Test ◽  
Static Stretching ◽  
Proprioceptive Neuromuscular Facilitation ◽  
Before And After ◽  
Straight Leg Raise ◽  
Pain Patients ◽  
Group Effects

BACKGROUND: The cranio-cervical flexion exercise and sub-occipital muscle inhibition technique have been used to improve a forward head posture among neck pain patients with straight leg raise (SLR) limitation. However, little is known about the cranio-vertebral angle (CVA) and cervical spine range of motion (CROM) after applying stretching methods to the hamstring muscle. OBJECTIVE: To compare the immediate effects of static stretching and proprioceptive neuromuscular facilitation stretching on SLR, CVA, and CROM in neck pain patients with hamstring tightness. METHODS: 64 subjects were randomly allocated to the static stretching (n1= 32) or proprioceptive neuromuscular facilitation (n2= 32) stretching group. The SLR test was performed to measure the hamstring muscle’s flexibility and tightness between the two groups, with CROM and CVA also being measured. The paired t-test was used to compare all the variables within each group before and after the intervention. The independent t-test was used to compare the two groups before and after the stretching exercise. RESULTS: There were no between-group effects for any outcome variables (P> 0.05). However, all SLR, CVA, and CROM outcome variables were significantly improved within-group (P< 0.05). CONCLUSIONS: There were no between-group effects for any outcome variable; however, SLR, CVA, and CROM significantly improved within-group after the one-session intervention in neck pain patients with hamstring tightness.

Mid-sagittal canal diameter and vertebral body/canal ratio of the cervical spine in Koreans

1994 ◽  
Vol 35 (4) ◽  
pp. 446 ◽  
Author(s):  
Hwan Mo Lee ◽  
Nam Hyun Kim ◽  
Ho Jeong Kim ◽  
In Hyuk Chung
Keyword(s):  
Cervical Spine ◽  
Vertebral Body ◽  
Canal Diameter

The influence of fixed sagittal plane centers of rotation on motion segment mechanics and range of motion in the cervical spine

2013 ◽  
Vol 46 (7) ◽  
pp. 1369-1375 ◽  
Author(s):  
Brian P. Kelly ◽  
Nephi A. Zufelt ◽  
Elizabeth J. Sander ◽  
Denis J. DiAngelo
Keyword(s):  
Cervical Spine ◽  
Range Of Motion ◽  
Sagittal Plane ◽  
Motion Segment

scholarly journals 3D kinematic analysis of patients’ gait before and after unilateral total hip replacement

2020 ◽  
Vol 22 (2) ◽  
Author(s):  
Kateřina Kolářová ◽  
Tomáš Vodička ◽  
Michal Bozděch ◽  
Martin Repko
Keyword(s):  
Range Of Motion ◽  
Total Hip Replacement ◽  
Kinematic Analysis ◽  
Hip Replacement ◽  
Sagittal Plane ◽  
Frontal Plane ◽  
Step Length ◽  
Total Hip ◽  
Before And After ◽  
Analysis System

Purpose: The purpose of the study was to describe changes in the kinematic parameters in the patients’ gait after total hip replacement. Methods: Research group of men in the end stage of osteoarthritis indicated to the THR (n = 10; age 54.1 ± 7.5 years; weight 92.2 ± 9.6 kg; height 179.7 ± 5.9 cm). All participants underwent a total of three measurements: before surgery, 3 and 6 months after the surgery. Using the 3D kinematic analysis system, the patients’ gait was recorded during each measurement session and kinematic analysis was carried out. The parameters that were monitored included the sagittal range of motion while walking in the ankle, the knee and the hip joints of the operated and the unoperated limb, and the range in the hip joint’s frontal plane, the rotation of pelvis in the frontal and transverse planes, as well as the speed of walking and the walking step length. Results: Significant increases were found in sagittal range of motion in the operated hip joint, sagittal range of motion in the ankle joint on the unoperated side and in the walking step length of the unoperated limb. Conclusions: During walking after a THR, the sagittal range of motion in the ankle of the unoperated limb increases. Also, the range of motion in the sagittal plane on the operated joint increases, which is related to the lengthening of the step of the unoperated lower limb.

SEISMIC ASSESSMENT OF CONTEMPORARY VERSUS OLD URBAN FRAME BUILDINGS

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
ABDELRAHMAN ASHRI ◽  
ANAS ISSA ◽  
Aman Mwafy
Keyword(s):  
Comparative Study ◽  
Lateral Force ◽  
Fragility Functions ◽  
Seismic Code ◽  
Earthquake Losses ◽  
Relative Safety ◽  
Safety Margins ◽  
Before And After ◽  
Benchmark Structures ◽  
The Comparative Study

This comparative study probabilistically assesses the relative safety margins of code-compliant and pre-seismic code RC buildings with different heights in a region of medium seismicity. Detailed structural design and fiber-based modeling of six benchmark structures, namely two code-compliant buildings and two pre-code structures before and after retrofit, are undertaken to develop fragility functions using several earthquake records representing the most critical seismic scenario in the study area. Several inelastic dynamic analyses are performed to assess the seismic response and derive a range of fragility functions for the six benchmark buildings. Compared with contemporary structures, the study highlights the vulnerability of pre-code buildings due to the insufficient stiffness, strength, and ductility provided by their lateral force resisting systems. A practical retrofit solution for pre-code structures is subsequently assessed using the methodology adopted for other modern and old buildings. The probabilistic assessment results confirmed the comparable seismic performance of the retrofitted and code-conforming buildings. The comparative study, which provided insights into the differences between code-compliant versus pre-seismic code buildings before and after retrofit, contributes to reducing earthquake losses and improving community seismic resilience in earthquake-prone regions.

Reflexive Response of Neck Muscle to Sudden Perturbation after Prolonged Smartphone Use

2021 ◽  
Vol 65 (1) ◽  
pp. 1250-1253
Author(s):  
Eunjee Kim ◽  
Donghyun Song ◽  
Dasom Park ◽  
Hyorim Kim ◽  
Gwanseob Shin
Keyword(s):  
Cervical Spine ◽  
Muscle Activation ◽  
Neck Muscle ◽  
Spinal Stability ◽  
Delayed Onset ◽  
Activation Level ◽  
Before And After ◽  
Smartphone Use ◽  
Head Stability ◽  
Passive Stretch

Prolonged smartphone use induces passive stretch of neck tissues and muscle fatigue, affecting spinal stability and pain. It is necessary to evaluate the effect of smartphone use on the reflexive response to detect the changes in neck tissues and head stability. A laboratory experiment (n=10) was conducted to investigate the reflexive response of neck muscle to perturbation after 30 minutes of smartphone use. Neck extensor muscle activation and its activation timing to perturbation were investigated before and after smartphone use. Head angle and muscle activation level were collected during smartphone use. During smartphone use, muscle activation gradually increased. After smartphone use, neck muscles showed a higher activation level and significantly delayed onset to perturbation. Smartphone use changed the reflexive response of the neck muscle. Further study is needed to investigate the association between smartphone use and neuromuscular changes to the tissues of the cervical spine.

Functional Role of the Superior Articular Facets of the Atlas in the Enhancement of Craniovertebral Junction Stability

2010 ◽  
Author(s):  
Richard C. Hallgren ◽  
Erik Cattrysse ◽  
Jesse M. Zrull
Keyword(s):  
Cervical Spine ◽  
Sagittal Plane ◽  
Craniovertebral Junction ◽  
Transverse Plane ◽  
Automobile Accidents ◽  
Automobile Accident ◽  
Significant Difference ◽  
Posterior Translation ◽  
Developmental Variations

Whiplash distortions of the cervical spine, occurring during the retraction phase of a rear end automobile accident, are known to cause posterior translation of the head relative to the chest and shoulders [1,2]. This anteroposterior shear produces sagittal plane rotation of the cervical spine which results in relative flexion between the occiput and the atlas (Fig. 1). This study demonstrates that there is a significant difference between the average angles of the anterior aspects and the posterior aspects of the superior facets of the atlas with respect to a horizontal (transverse) plane at P<0.01. We hypothesize that developmental variations in some individuals will allow excessive posterior translation of the head during rear end automobile accidents, and that this excessive motion may increase the risk of sustaining a whiplash-type injury for some individuals.

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