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The adult head has been studied extensively and computationally modeled for impact, however there have been few studies that attempt to quantify the mechanical properties of the pediatric skull. Likewise, little documentation of pediatric anthropometry exists. We hypothesize that the properties of the human pediatric skull differ from the human adult skull and exhibit viscoelastic structural properties. Quasi-static and dynamic compression tests were performed using the whole head of three human neonate specimens (ages 1 to 11 days old). Whole head compression tests were performed in a MTS servo-hydraulic actuator. Testing was conducted using nondestructive quasi-static, and constant velocity protocols in the anterior-posterior and right-left directions. In addition, the pediatric head specimens were dropped from 15cm and 30cm and impact force-time histories were measured for five different locations: vertex, occiput, forehead, right and left parietal region.

This study investigated the mechanisms of traumatic rupture of the aorta (TRA). Eight unembalmed human cadavers were tested using various dynamic blunt loading modes. Impacts were conducted using a 32-kg impactor with a 152-mm face, and high-speed seatbelt pretensioners. High-speed biplane x-ray was used to visualize aortic motion within the mediastinum, and to measure deformation of the aorta. An axillary thoracotomy approach was used to access the peri-isthmic region to place radiopaque markers on the aorta. The cadavers were inverted for testing. Clinically relevant TRA was observed in seven of the tests. Peak average longitudinal Lagrange strain was 0.644, with the average peak for all tests being 0.208 ± 0.216. Peak intraluminal pressure of 165 kPa was recorded. Longitudinal stretch of the aorta was found to be a principal component of injury causation. Stretch of the aorta was generated by thoracic deformation, which is required for injury to occur.

The absence of constitutive data on muscle has limited the development of models of cervical spinal dynamics and our understanding of the forces developed in the cervical spine during impact injury. Therefore, the purpose of this study is to characterize the structural and material properties of skeletal muscle. The structural responses of the tibialis anterior of the rabbit were characterized in the passive state using the quasi-linear theory of viscoelasticity (r = 0.931 ± 0.032). In passive muscle, the average modulus at 20% strain was 1.75 ± 1.18, 2.45 ± 0.80, and 2.79 ± 0.67 MPa at test rates of 4, 40, and 100 cm·s-1, respectively. In stimulated muscle, the mean initial stress was 0.44 ± 0.15 MPa and the average modulus was 0.97 ± 0.34 MPa. These data define a corridor of responses of skeletal muscle during injury, and are in a form suitable for incorporation into computational models of cervical spinal dynamics.

For more than 20 years, field research and laboratory testing has consistently demonstrated that wearing a seat belt dramatically reduces the risk of occupant death or serious injury in motor vehicle crashes [1, 2]. The injury prevention benefits of seat belts require that they remain fastened during collisions. Federal Motor Vehicle Safety Standards set forth seat belt buckle performance requirements to address buckle performance in accident conditions. However, several theories of buckle release or separation exist including: false latch, inadvertent release, and inertial release. Forensic investigations of vehicle crashes would benefit with diagnostic criteria which could distinguish between a buckle separation, a properly restrained occupant, and an unused or stowed seat belt. In the unlikely event of buckle separation, entanglement with the webbing would be expected if the occupant moves substantially as a result of the crash forces.

Tensile neck injuries are amongst the most serious cervical injuries. However, because neither reliable human cervical tensile tolerance data nor tensile structural data are currently available, the quantification of tensile injury risk is limited. The purpose of this study is to provide previously unavailable kinetic and tolerance data for the ligamentous cervical spine and determine the effect of neck muscle on tensile load response and tolerance. Using six male human cadaver specimens, isolated ligamentous cervical spine tests (occiput - T1) were conducted to quantify the significant differences in kinetics due to head end condition and anteroposterior eccentricity of the tensile load. The spine was then separated into motion segments for tension failure testing. The upper cervical spine tolerance of 2400 ± 270 N (occiput- C2) was found to be significantly greater (p< 0.01) than the lower cervical spine tolerance of 1780 ± 230 N (C4-C5 and C6-C7 segments).

Based on an analysis of the National Automotive Sampling System (NASS) database from calendar years 1995-2000, over 30,000 fractures and dislocations of the knee-thigh-hip (KTH) complex occur in frontal motor-vehicle crashes each year in the United States. This analysis also shows that the risk of hip injury is generally higher than the risks of knee and thigh injuries in frontal crashes, that hip injuries are occurring to adult occupants of all ages, and that most hip injuries occur at crash severities that are equal to, or less than, those used in FMVSS 208 and NCAP testing. Because previous biomechanical research produced mostly knee or distal femur injuries, and because knee and femur injuries were frequently documented in early crash investigation data, the femur has traditionally been viewed as the weakest part of the KTH complex.