3D Dynamic Modeling of the Head-Neck Complex for Fast Eye and Head Orientation Movements Research

Abstract Background All current total hip arthroplasty (THA) systems are modular in design. Only during the operation femoral head and stem get connected by a Morse taper junction. The junction is realized by hammer blows from the surgeon. Decisive for the junction strength is the maximum force acting once in the direction of the neck axis, which is mainly influenced by the applied impulse and surrounding soft tissues. This leads to large differences in assembly forces between the surgeries. This study aimed to quantify the assembly forces of different surgeons under influence of surrounding soft tissue. Methods First, a measuring system, consisting of a prosthesis and a hammer, was developed. Both components are equipped with a piezoelectric force sensor. Initially, in situ experiments on human cadavers were carried out using this system in order to determine the actual assembly forces and to characterize the influence of human soft tissues. Afterwards, an in vitro model in the form of an artificial femur (Sawbones Europe AB, Malmo, Sweden) with implanted measuring stem embedded in gelatine was developed. The gelatine mixture was chosen in such a way that assembly forces applied to the model corresponded to those in situ. A study involving 31 surgeons was carried out on the aforementioned in vitro model, in which the assembly forces were determined. Results A model was developed, with the influence of human soft tissues being taken into account. The assembly forces measured on the in vitro model were, on average, 2037.2 N ± 724.9 N, ranging from 822.5 N to 3835.2 N. The comparison among the surgeons showed no significant differences in sex (P = 0.09), work experience (P = 0.71) and number of THAs performed per year (P = 0.69). Conclusions All measured assembly forces were below 4 kN, which is recommended in the literature. This could lead to increased corrosion following fretting in the head-neck interface. In addition, there was a very wide range of assembly forces among the surgeons, although other influencing factors such as different implant sizes or materials were not taken into account. To ensure optimal assembly force, the impaction should be standardized, e.g., by using an appropriate surgical instrument.

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COMPARATIVE MEASUREMENTS OF HEAD ANGULAR MOVEMENTS USING A CAMERA SYSTEM AND A GYROSCOPE SYSTEM

Acta Polytechnica ◽

10.14311/ap.2014.54.0295 ◽

2014 ◽

Vol 54 (4) ◽

pp. 295-300 ◽

Cited By ~ 1

Author(s):

Vladimir Socha ◽

Patrik Kutilek ◽

Ondrej Cakrt ◽

Rudolf Cerny

Keyword(s):

Head Movements ◽

Head Orientation ◽

Quiet Stance ◽

Body Segment ◽

Mean Velocity ◽

Camera System ◽

Rehabilitation Process ◽

Gyroscope System ◽

The Mean ◽

2D Data

Assessments of body-segment angular movements are very important in the rehabilitation process. Head angular movements are measured and analyzed for use in studies of stability and posture. However, there is no methodology for assessing angular movements of the head, and it has not been verified whether data measured by fundamentally different MoCap systems will lead to the same results. In this study, we used a camera system and a 3DOF orientation tracker placed on the subject’s head, and measured inclination (roll) and flexion (pitch) during quiet stance. The total length and the mean velocity of the traces of the pitch versus roll plots were used to measure and analyze head orientation. Using these methods, we are able to model the distribution of the measured 2D data, and to evaluate stability and posture. The results show that the total lengths and the mean velocities related to the 3DOF orientation tracker do not differ significantly from the total lengths and the mean velocities of traces related to the IR medical camera. We also found that the systems are not interchangeable, and that the same type of system must be used each time. The designed methods can be used for studies not only of head movements but also of movements of other segments of the human body, and can be used to compare other types of MoCap systems, depending on the requirements for a specific rehabilitation examination.

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Contribution of Head Movement to Gaze Command Coding in Monkey Frontal Cortex and Superior Colliculus

Journal of Neurophysiology ◽

10.1152/jn.00330.2003 ◽

2003 ◽

Vol 90 (4) ◽

pp. 2770-2776 ◽

Cited By ~ 26

Author(s):

Julio C. Martinez-Trujillo ◽

Eliana M. Klier ◽

Hongying Wang ◽

J. Douglas Crawford

Keyword(s):

Superior Colliculus ◽

Neural Control ◽

Significant Contribution ◽

Head Movements ◽

Vector Model ◽

Gaze Control ◽

Gaze Shift ◽

Visual Model ◽

The Gaze ◽

Supplementary Eye Fields

Most of what we know about the neural control of gaze comes from experiments in head-fixed animals, but several “head-free” studies have suggested that fixing the head dramatically alters the apparent gaze command. We directly investigated this issue by quantitatively comparing head-fixed and head-free gaze trajectories evoked by electrically stimulating 52 sites in the superior colliculus (SC) of two monkeys and 23 sites in the supplementary eye fields (SEF) of two other monkeys. We found that head movements made a significant contribution to gaze shifts evoked from both neural structures. In the majority of the stimulated sites, average gaze amplitude was significantly larger and individual gaze trajectories were significantly less convergent in space with the head free to move. Our results are consistent with the hypothesis that head-fixed stimulation only reveals the oculomotor component of the gaze shift, not the true, planned goal of the movement. One implication of this finding is that when comparing stimulation data against popular gaze control models, freeing the head shifts the apparent coding of gaze away from a “spatial code” toward a simpler visual model in the SC and toward an eye-centered or fixed-vector model representation in the SEF.

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Monophasic Synovial Sarcoma of the Lower Eyelid: Rare Tumor involving Rare Site

International Journal of Head and Neck Surgery ◽

10.5005/jp-journals-10001-1253 ◽

2015 ◽

Vol 6 (4) ◽

pp. 190-192

Author(s):

TN Suresh ◽

A Sagayaraj ◽

TR Harshita ◽

Azeem Mohiyuddin

Keyword(s):

Synovial Sarcoma ◽

Soft Tissues ◽

Large Mass ◽

Lower Eyelid ◽

Anterior Wall ◽

Rare Tumor ◽

Tissue Mass ◽

Rare Site ◽

Medial Maxillectomy ◽

Head Neck

ABSTRACT Aim Synovial sarcoma of eyelid is extremely rare. We are reporting a case of massive synovial sarcoma of lower eyelid extending to soft tissues over the anterior wall of maxilla. Case report A 58-year-old male patient presented with a large mass involving the left lower eyelid and extending over the soft tissues of the anterior wall of the maxilla since 15 years. Clinical examination showed a firm soft tissue mass measuring 16 × 8 × 6 cm involving the left lower eyelid and extending to soft tissues over the maxilla. The mass showed ulceration and was bleeding on touch. Computed tomography scan showed an exophytic lobulated heterogeneously enhancing mass lesion with intense enhancing capsule measuring 14 × 9.3 × 8.4 cm with few internal areas of necrosis arising from left preseptal region. The lesion was causing erosion at the medial wall and floor of left orbit. It was clinically diagnosed as hemangiopericytoma. The patient was taken up for surgery and wide excision of the tumor and medial maxillectomy was done. The defect was reconstructed with a glabellar flap. How to cite this article Mohiyuddin A, Sagayaraj A, Harshita TR, Suresh TN. Monophasic Synovial Sarcoma of the Lower Eyelid: Rare Tumor involving Rare Site. Int J Head Neck Surg 2015;6(4):190-192.

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Thermal reception in the Mexican Lance-head rattlesnake, Crotalus polystictus

10.7287/peerj.preprints.26599v1 ◽

2018 ◽

Author(s):

Octavio I Martínez Vaca-León ◽

Javier Manjarrez

Keyword(s):

Behavioral Response ◽

Head Movements ◽

Head Orientation ◽

Thermal Thresholds ◽

Interspecific Differences ◽

Neurophysiological Mechanisms ◽

Thermal Detection ◽

Tongue Flicks ◽

Thermal Stimuli ◽

Stimulus Shape

The sensory systems of Boidae and Crotalinae snakes detect subtle differences of thermal infrared energy. The complexity of this ability involves neurophysiological mechanisms with interspecific differences in the anatomy of thermoreceptor organs and functionally in thermal detection ranges and thermal thresholds, with ecological correlations that influence the thermo-reception. However, little is known about the information these snakes obtain and use from infrared radiation. We analyzed the behavioral response of adult Mexican Lance-head Rattlesnakes (Crotalus polystictus) to static thermal stimuli, evaluating the influence of distance from the snake of the thermal stimuli, and its lizard-like or mouse-like shape. The results reveal that C. polystictus is able to detect static thermal stimuli located from 20 to 200 cm away. Head movements and tongue-flicks were the most frequently performed behaviors, which suggests they are behaviors that can facilitate the detection of subtle differences in temperature of static stimuli. In addition, we suggest that stimulus shape and temperature are important in the timing of head orientation and frequency of tongue-flicks. We discuss the possible methodological and sensory implications of this behavioral response in C. polystictus.

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Thermal reception in the Mexican Lance-head rattlesnake, Crotalus polystictus

10.7287/peerj.preprints.26599 ◽

2018 ◽

Author(s):

Octavio I Martínez Vaca-León ◽

Javier Manjarrez

Keyword(s):

Behavioral Response ◽

Head Movements ◽

Head Orientation ◽

Thermal Thresholds ◽

Interspecific Differences ◽

Neurophysiological Mechanisms ◽

Thermal Detection ◽

Tongue Flicks ◽

Thermal Stimuli ◽

Stimulus Shape

The sensory systems of Boidae and Crotalinae snakes detect subtle differences of thermal infrared energy. The complexity of this ability involves neurophysiological mechanisms with interspecific differences in the anatomy of thermoreceptor organs and functionally in thermal detection ranges and thermal thresholds, with ecological correlations that influence the thermo-reception. However, little is known about the information these snakes obtain and use from infrared radiation. We analyzed the behavioral response of adult Mexican Lance-head Rattlesnakes (Crotalus polystictus) to static thermal stimuli, evaluating the influence of distance from the snake of the thermal stimuli, and its lizard-like or mouse-like shape. The results reveal that C. polystictus is able to detect static thermal stimuli located from 20 to 200 cm away. Head movements and tongue-flicks were the most frequently performed behaviors, which suggests they are behaviors that can facilitate the detection of subtle differences in temperature of static stimuli. In addition, we suggest that stimulus shape and temperature are important in the timing of head orientation and frequency of tongue-flicks. We discuss the possible methodological and sensory implications of this behavioral response in C. polystictus.

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Head Immobilization can Impair Jaw Function

Journal of Dental Research ◽

10.1177/154405910608501105 ◽

2006 ◽

Vol 85 (11) ◽

pp. 1001-1005 ◽

Cited By ~ 22

Author(s):

B. Häggman-Henrikson ◽

E. Nordh ◽

H. Zafar ◽

P.-O. Eriksson

Keyword(s):

Neck Muscles ◽

Head Movements ◽

Myoelectric Activity ◽

Neck Muscle ◽

Head Fixation ◽

Jaw Opening ◽

Simultaneous Registration ◽

Jaw Function ◽

Mandibular Movements ◽

Head Neck

Findings that jaw-opening/-closing relies on both mandibular and head movements suggest that jaw and neck muscles are jointly activated in jaw function. This study tested the hypothesis that rhythmic jaw activities involve an active repositioning of the head, and that head fixation can impair jaw function. Concomitant mandibular and head-neck movements were recorded during rhythmic jaw activities in 12 healthy adults, with and without fixation of the head. In four participants, the movement recording was combined with simultaneous registration of myoelectric activity in jaw and neck muscles. The results showed neck muscle activity during jaw opening with and without head fixation. Notably, head fixation led to reduced mandibular movements and shorter duration of jaw-opening/-closing cycles. The findings suggest recruitment of neck muscles in jaw activities, and that head fixation can impair jaw function. The results underline the jaw and neck neuromuscular relationship in jaw function.

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Extraskeletal Chondroma: Another Diagnostic Possibility for a Soft Tissue Axillary Mass in an Adolescent

Case Reports in Orthopedics ◽

10.1155/2011/309328 ◽

2011 ◽

Vol 2011 ◽

pp. 1-4 ◽

Cited By ~ 6

Author(s):

Ibrahim Adaletli ◽

Tal Laor ◽

Hong Yin ◽

Daniel J. Podberesky

Keyword(s):

Differential Diagnosis ◽

Soft Tissue ◽

Oral Cavity ◽

Soft Tissues ◽

Soft Tissue Mass ◽

Tissue Mass ◽

Cartilaginous Tumor ◽

Axillary Mass ◽

Hands And Feet ◽

Head Neck

Extraskeletal chondroma is a benign cartilaginous tumor that occurs predominantly in the soft tissues near small joints of the hands and feet. There are rare reports of the lesion in other sites, such as the head, neck, trunk, oral cavity, larynx, and pharynx. We present a case of an axillary mass in a 15-year-old girl who underwent MRI examination and resection, with the ultimate diagnosis of an extraskeletal chondroma, in order to expand the differential diagnosis of an axillary soft tissue mass in an adolescent.

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Design of Charge-Balanced Time-Optimal Stimuli for Spiking Neuron Oscillators

Neural Computation ◽

10.1162/neco_a_00643 ◽

2014 ◽

Vol 26 (10) ◽

pp. 2223-2246 ◽

Cited By ~ 7

Author(s):

Isuru S. Dasanayake ◽

Jr-Shin Li

Keyword(s):

Optimal Control ◽

Neural Control ◽

Phase Response Curve ◽

Fundamental Problem ◽

External Control ◽

Control Input ◽

Optimal Controls ◽

Oscillatory Systems ◽

Time Optimal ◽

Phase Models

In this letter, we investigate the fundamental limits on how the interspike time of a neuron oscillator can be perturbed by the application of a bounded external control input (a current stimulus) with zero net electric charge accumulation. We use phase models to study the dynamics of neurons and derive charge-balanced controls that achieve the minimum and maximum interspike times for a given bound on the control amplitude. Our derivation is valid for any arbitrary shape of the phase response curve and for any value of the given control amplitude bound. In addition, we characterize the change in the structures of the charge-balanced time-optimal controls with the allowable control amplitude. We demonstrate the applicability of the derived optimal control laws by applying them to mathematically ideal and experimentally observed neuron phase models, including the widely studied Hodgkin-Huxley phase model, and by verifying them with the corresponding original full state-space models. This work addresses a fundamental problem in the field of neural control and provides a theoretical investigation to the optimal control of oscillatory systems.

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A Female Ligamentous Cervical Spine Finite Element Model Validated for Physiological Loads

Journal of Biomechanical Engineering ◽

10.1115/1.4032966 ◽

2016 ◽

Vol 138 (6) ◽

Cited By ~ 15

Author(s):

Jonas Östh ◽

Karin Brolin ◽

Mats Y. Svensson ◽

Astrid Linder

Keyword(s):

Finite Element ◽

Cervical Spine ◽

Soft Tissues ◽

Cervical Vertebrae ◽

Female Population ◽

Female Model ◽

Intervertebral Disks ◽

Flexion Extension ◽

Spine Model ◽

Nonlinear Elastic

Mathematical cervical spine models allow for studying of impact loading that can cause whiplash associated disorders (WAD). However, existing models only cover the male anthropometry, despite the female population being at a higher risk of sustaining WAD in automotive rear-end impacts. The aim of this study is to develop and validate a ligamentous cervical spine intended for biomechanical research on the effect of automotive impacts. A female model has the potential to aid the design of better protection systems as well as improve understanding of injury mechanisms causing WAD. A finite element (FE) mesh was created from surface data of the cervical vertebrae of a 26-year old female (stature 167 cm, weight 59 kg). Soft tissues were generated from the skeletal geometry and anatomical literature descriptions. Ligaments were modeled with nonlinear elastic orthotropic membrane elements, intervertebral disks as composites of nonlinear elastic bulk elements, and orthotropic anulus fibrosus fiber layers, while cortical and trabecular bones were modeled as isotropic plastic–elastic. The model has geometrical features representative of the female cervical spine—the largest average difference compared with published anthropometric female data was the vertebral body depth being 3.4% shorter for the model. The majority the cervical segments compare well with respect to biomechanical data at physiological loads, with the best match for flexion–extension loads and less biofidelity for axial rotation. An average female FE ligamentous cervical spine model was developed and validated with respect to physiological loading. In flexion–extension simulations with the developed female model and an existing average male cervical spine model, a greater range of motion (ROM) was found in the female model.

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