An Analytical Viscoelastic Model of the Head in Blunt Impacts

2008 ◽  
Author(s):  
Shahab Baghaei ◽  
Ali Sadegh ◽  
Mohamad Rajaai
Keyword(s):  
Mathematical Model ◽  
Finite Element ◽  
Spherical Shell ◽  
Head Injuries ◽  
Head Impacts ◽  
Closed Head Injuries ◽  
Brain Motion ◽  
Closed Head ◽  
The Impact ◽  
The Brain

The relative motion between the brain and skull and an increase in contact and shear stresses in the meningeal region could cause traumatic closed head injuries due to vehicular collisions, sport accidents and falls. There are many finite element studies of the brain/head models, but limited analytical models. The goal of this paper is to mathematically model subarachnoid space and the meningeal layers and to investigate the motion of the brain relative to the skull during blunt head impacts. The model consists of an elastic spherical shell representing the skull containing a visco-elastic solid material as the brain and a visco-elastic interface, which models the meningeal layers between the brain and the skull. In this study, the shell (the head) is moved toward a barrier and comes in contact with the barrier. Consequently, the skull deforms elastically and the brain is excited to come in contact with the skull. The viscoelastic characteristics of the interface (consisting of springs and dampers) are determined using experimental results of Hardy et al. [5]. Hertzian contact theory and Newtonian method are employed to acquire time dependant equations for the problem. The governing nonlinear integro-differential equations are formed and are solved using 4th order Runge Kutta method and elastic deformation of spherical shell, brain motion during the impact, and contact conditions between the brain and the skull are evaluated. Furthermore, some important mechanical parameters such as acceleration, impact force, and the impact time duration are also specified. The results of the analytical method are validated by performing an explicit finite element analysis. Acceptable agreement between these two methods is observed. The results of the analytical investigation give the contact threshold of the skull/brain, and represent the relevant velocity of this event. Furthermore, the impact analysis in different velocities is performed in order to compare the transmitted forces and the impact durations in different cases. It is concluded that the proposed mathematical model can predict head impacts in accidents and is capable in determining the relative brain motion of the skull and the brain. The mathematical model could be employed by other investigators to parametrically study the traumatic closed head injuries and hence to propose new head injury criteria.

Auditory brain stem responses (ABR) in patients with acute severe closed head injuries

1988 ◽  
Vol 102 (9) ◽  
pp. 755-759 ◽  
Author(s):  
Samy Elwany
Keyword(s):  
Brain Stem ◽  
Head Injuries ◽  
Grading System ◽  
Closed Head Injuries ◽  
Injury Management ◽  
Auditory Brain Stem ◽  
Management Protocol ◽  
Closed Head ◽  
Interpeak Latency ◽  
The Brain

AbstractABR were recorded in 68 cases suffering from severe acute closed head injuries. Abnormal recordings were observed in 60 per cent of patients, and the abnormalities ranged from prolongation of the interpeak latency intervals to complete absence of auditory brain stem activity. Based on the results obtained, a grading system was developed and correlated with the neurological outcome. It was concluded that ABR is a useful diagnostic and prognostic tool which can provide valuable information about the function of the brain stem in these patients. Inclusion of ABR studies in the head injury management protocol is strongly recommended.

scholarly journals Epidemiology of Cheerleading Fall-Related Injuries in the United States

2009 ◽  
Vol 44 (6) ◽  
pp. 578-585 ◽  
Author(s):  
Brenda J. Shields ◽  
Gary A. Smith
Keyword(s):  
Cruciate Ligament ◽  
Head Injuries ◽  
The United States ◽  
Severe Injuries ◽  
Closed Head Injuries ◽  
Wood Floor ◽  
Closed Head ◽  
Serious Injury ◽  
The Impact ◽  
Fall Height

Abstract Context: Over the past several decades, cheerleaders have been performing fewer basic maneuvers and more gymnastic tumbling runs and stunts. As the difficulty of these maneuvers has increased, cheerleading injuries have also increased. Objective: To describe the epidemiology of cheerleading fall-related injuries by type of cheerleading team and event. Design: Prospective injury surveillance study. Setting: Participant exposure and injury data were collected from US cheerleading teams via the Cheerleading RIO (Reporting Information Online) surveillance tool. Patients or Other Participants: Athletes from 412 enrolled cheerleading teams who participated in official, organized cheerleading practices, pep rallies, athletic events, or cheerleading competitions. Main Outcome Measure(s): The numbers and rates of cheerleading fall-related injuries during a 1-year period (2006–2007) are reported. Results: A total of 79 fall-related injuries were reported during the 1-year period. Most occurred during practice (85%, 67/79) and were sustained by high school cheerleaders (51%, 40/79). A stunt or pyramid was being attempted in 89% (70/79) of cases. Fall heights ranged from 1 to 11 ft (0.30–3.35 m) (mean  =  4.7 ± 2.0 ft [1.43 ± 0.61 m]). Strains and sprains were the most common injuries (54%, 43/79), and 6% (5/79) of the injuries were concussions or closed head injuries. Of the 15 most serious injuries (concussions or closed head injuries, dislocations, fractures, and anterior cruciate ligament tears), 87% (13/15) were sustained while the cheerleader was performing on artificial turf, grass, a traditional foam floor, or a wood floor. The fall height ranged from 4 to 11 ft (1.22–1.52 m) for 87% of these cases (13/15). Conclusions: Cheerleading-related falls may result in severe injuries and even death, although we report no deaths in the present study. The risk for serious injury increases as fall height increases or as the impact-absorbing capacity of the surfacing material decreases (or both).

An Experimental Study of Package Cushioning for the Human Head

1976 ◽  
Vol 43 (3) ◽  
pp. 469-474
Author(s):  
Y. King Liu ◽  
K. B. Chandran
Keyword(s):  
Mathematical Model ◽  
Animal Experiments ◽  
Human Head ◽  
Head Impacts ◽  
Closed Head ◽  
The Mathematical Model ◽  
Experimental Pressure ◽  
The Brain ◽  
Good Agreement

An experiment was performed to determine the container acceleration and pressure distribution in a Plexiglass cylinder, filled either with water or 3 percent set-gelatin, and impacted against a wall. This experiment serves to quantitatively validate a theoretical model simulating an one-dimensional closed-head impact given earlier. The experiments showed important differences between the theoretical and experimental pressure measurements. When the medium contained within the cylinder was water the coup pressure as found by experiment, was higher than the mathematical model prediction while the contrecoup pressure was in good agreement. When the container was filled with a set gel, the coup pressure was in agreement with the mathematical model but the contrecoup pressure is considerably lower than the calculated result. Since the brain is neither water nor gel, in vivo animal experiments are needed to obtain meaningful tolerance limits for injury due to cavitation at the contrecoup region in closed-head impacts.

scholarly journals Measured Impact

2018 ◽  
Vol 140 (01) ◽  
pp. 42-45
Author(s):  
James G. Skakoon
Keyword(s):  
Finite Element ◽  
Corpus Callosum ◽  
Degrees Of Freedom ◽  
Head Injuries ◽  
Analysis Model ◽  
Element Analysis ◽  
Falx Cerebri ◽  
Institute Of Technology ◽  
The Impact ◽  
The Brain

This article focuses on an innovative methodology developed by researchers at Stanford University. The new way of measuring the forces that cause head injuries aim to change how engineers protect professional and weekend athletes. By embedding both accelerometers and gyroscopes within the mouth guards, the laboratory tracked all six degrees of freedom and slashed data errors to 10 percent or less. According to one of the developer, since the upper teeth are firmly coupled to the bones of the cranium, the mouthguards can provide data accurate enough for the lab to use in finite element models to describe what is happening inside the brain. The team input the incident’s kinematics data into a finite element analysis model of the brain developed by the KTH Royal Institute of Technology in Sweden. This enabled them to simulate how different structures within the brain responded to the impact. The computer simulation showed that the falx cerebri appears to be the culprit. It is a rigid vertical sheet that separates the brain’s two lobes. It lies right above the corpus callosum and extends upward, attaching to the skull at the very top. It conducts impact energy from the skull deep into the brain, where it oscillates and induces strain in the corpus callosum.

Closed Head Injuries in Athletes

1990 ◽  
Vol 9 (2) ◽  
pp. 247-261 ◽  
Author(s):  
Lawrence B. Lehman ◽  
Steven J. Ravich
Keyword(s):  
Head Injuries ◽  
Closed Head Injuries ◽  
Closed Head

scholarly journals A Retrospective Analysis of Softball-Related Head and Facial Injuries Treated in United States Emergency Departments, 2013-2017

2019 ◽  
Vol 7 (2) ◽  
pp. 232596711982566 ◽  
Author(s):  
John S. Strickland ◽  
Marie Crandall ◽  
Grant R. Bevill
Keyword(s):  
United States ◽  
Head Injuries ◽  
The United States ◽  
Weighted Estimate ◽  
Body Parts ◽  
Facial Injuries ◽  
Closed Head Injuries ◽  
Closed Head ◽  
The Mean ◽  
Race Ethnicity

Background: Softball is a popular sport played through both competitive and recreational leagues. While head and facial injuries are a known problem occurring from games, little is known about the frequency or mechanisms by which they occur. Purpose: To analyze head/face injury diagnoses and to identify the mechanisms associated with such injuries. Study Design: Descriptive epidemiological study. Methods: A public database was used to query data related to head/facial injuries sustained in softball. Data including age, sex, race/ethnicity, injury diagnosis, affected body parts, disposition, incident location, and narrative descriptions were collected and analyzed. Results: A total of 3324 head and face injuries were documented in the database over the time span of 2013 to 2017, resulting in a nationwide weighted estimate of 121,802 head/face injuries occurring annually. The mean age of the players was 21.5 ± 14.4 years; 72.1% of injured players were female, while 27.9% were male. The most common injury diagnoses were closed head injuries (22.0%), contusions (18.7%), concussions (17.7%), lacerations (17.1%), and fractures (15.1%). The overwhelming majority of injuries involved being struck by a ball (74.3%), followed by colliding with another player (8.3%), colliding with the ground or a fixed object (5.0%), or being struck by a bat (2.8%). For those injuries caused by a struck-by-ball incident, most occurred from defensive play (83.7% were fielders struck by a hit or thrown ball) as opposed to offensive play (12.3% were players hit by a pitch or runners struck by a ball). Although helmet usage was poorly tracked in the database, female players (1.3%) were significantly more likely to have been wearing a helmet at the time of injury than were male players (0.2%) ( P = .002). Conclusion: The present study demonstrates that a large number of head and face injuries occur annually within the United States as a result of softball play. A variety of injuries were observed, with the majority involving defensive players being struck by the ball, which highlights the need for more focus on player safety by stronger adherence to protective headgear usage and player health monitoring.

The glial reaction in closed head injuries

1991 ◽  
Vol 17 (5) ◽  
pp. 407-414 ◽  
Author(s):  
D. A. CROOKS ◽  
C. L. SCHOLTZ ◽  
G. VOWLES ◽  
S. GREENWALD ◽  
S. EVANS
Keyword(s):  
Head Injuries ◽  
Closed Head Injuries ◽  
Glial Reaction ◽  
Closed Head

Airway complications in patients with closed-head injuries

1987 ◽  
Vol 8 (2) ◽  
pp. 91-96 ◽  
Author(s):  
Peggyann Nowak ◽  
Arnold M. Cohn ◽  
Mary Ann Guidice
Keyword(s):  
Head Injuries ◽  
Closed Head Injuries ◽  
Airway Complications ◽  
Closed Head
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