Biomechanics of Human Occupants in Simulated Rear Crashes: Documentation of Neck Injuries and Comparison of Injury Criteria

Cervical Spine Loads and Intervertebral Motions During Whiplash

“…Although the motions have been studied in numerous investigations (Cusick et al, 2001;Panjabi et al, 2005a), practically nothing is known about the magnitudes, caudal progression, and timing of the dynamic vertebral loads. The previous studies are limited to determination of the dynamic loads at the occipital condyles or T1 vertebra during simulated rear impacts (Mertz & Patrick, 1967;Siegmund et al, 2001;Tencer et al, 2002;Yoganandan et al, 2000). Ours is the first study to provide comprehensive simultaneous dynamic vertebral load and motion data, using a previously described and validated experimental model .…”

“…In vivo dynamic loads at the occipital condyles have been computed using inverse dynamics and head motion, acceleration, mass, and inertia data (Davidsson et al, 1999;Mertz & Patrick, 1967, 1971Ono et al, 1997;Siegmund et al, 2001;van den Kroonenberg et al, 1998). Even during in vitro simulations, only the loads at the occipital condyles in whole cadavers (Luan et al, 2000;Yoganandan et al, 2000) and at a load cell mounted at the base of a head-T1 specimen were reported (Stemper et al, 2003;Yoganandan & Pintar, 1997). Lastly, loads calculated using mathematical models have been reported only at the occipital condyles or T1 vertebra (Garcia & Ravani, 2003;Tencer et al, 2002;van der Horst, 2002).…”

Effects of abnormal posture on capsular ligament elongations in a computational model subjected to whiplash loading

“…Following the initiation of the postero-anterior thoracic acceleration, the cervical spinal column responds with an S-shaped curvature characterized by flexion in upper segments and extension in lower segments. Various experimental investigators, using models ranging from intact human cadavers, human volunteers, and isolated cervical ligamentous columns subjected to injurious and subinjurious loading, have identified that this non-physiologic cervical Scurvature plays a pivotal role in whiplash injury mechanisms (Cusick et al, 2001;Deng et al, 2000;Grauer et al, 1997;Kaneoka et al, 1999;Yoganandan et al, 2000). It has been hypothesized that the nonphysiologic curvature subjects the cervical facet joints to injurious loading patterns that include stretch of the capsular ligaments at the various facet joint levels Yoganandan et al, 2001).…”

“…Because pre-existing abnormal curvatures (straight and kyphotic) inherently alter the mechanisms of load transfer in the segmented cervical spinal column, the hypothesis pursued in the present investigation was that abnormal spinal curvature alters kinematics during whiplash by increasing facet joint ligament elongations during the time of non-physiologic S-curvature. The cervical facet joints are implicated in whiplash injury in clinical and biomechanical literature (Barnsley et al, 1994;Stemper et al, 2003;Yoganandan et al, 2000). Because motion and injury are related, increased capsular ligament elongations in abnormal spinal postures would indicate that spinal posture plays a role in whiplash by altering loading patterns on the cervical column to subject a specific population to an elevated likelihood of whiplash trauma.…”

Axial head rotation increases facet joint capsular ligament strains in automotive rear impact

“…Characteristics of the acceleration versus time pulse were based on T1 accelerations measured during a series of full-body PMHS rear impact experiments [58]. Impact severity was quantified using change in velocity (DV), computed as the integral of the T1 acceleration versus time pulse.…”