Facets, Public

A female head–neck model for rear impact simulations

Here is a study Professionally Integrated wants you to be aware of so you can help more patients be healthy and we can understand more about our patients and how our treatment helps. Make sure you show your patients the highlights I list below from.

By Jan 1,2017

Here is a study Professionally Integrated wants you to be aware of so you can help more patients be healthy and we can understand more about our patients and how our treatment helps. Make sure you show your patients the highlights I list below from this paper so you can educate them further.

Here is what the authors publish: ( In BOLD is from the paper, cut and paste to your notes our put at your front desk for your patients to see and encourage them to ask about it. After the bold type is my thoughts for you.)

“In this study, a finite element head and neck model of a 50th percentile female was validated in rear impacts. A previously validated ligamentous cervical spine model was complemented with a rigid body head, soft tissues and muscles. In both physiological flexion-extension motions and simulated rear impacts, the kinematic response at segment level was comparable to that of human subjects. Evaluation of ligament stress levels in simulations with varied initial cervical curvature revealed that if an individual assumes a more lordotic posture than the neutral, a higher risk of WAD might occur in rear impact.” Yes it says they are hurt more with an increased lordotic curve but you must read on.

“The maximal cervical strength of the model was 12.4 Nm in flexion, 31.0 Nm and 42.8 Nm in extension (with and without scapular muscles).” Take a look at how much stronger our necks are in extension compared to flexion, 3-4xs!!  Now, educating our patients on ergonomics, posture, and the NEED for care to allow us to minimize the flexion in their spine.


“The ligamentous cervical spine consists of approximately 116,000 elements; cortical bone is modelled with triangular shell elements, trabecular bone with tetrahedral elements, ligaments with orthotropic membrane elements, and intervertebral discs as composites of hexahedral elements and orthotropic quadrilateral membrane elements.”  116,000 elements!!!! Doctor, this is why at Professionally Integrated you hear me say “what structure was harmed or injured?”  Diagnosing our patients with a “sprain/strain” after a crash or injury is not enough. Insurance companies may argue that but this is the real world and we are talking about our patients health!  Many structures may be involved. Injuries can be very complex!

“Gender has been shown to be an important factor for the risk of sustaining Whiplash Associated Disorders (WAD); the risk for females sustaining symptoms is on average double that of males and in similar crash conditions even higher.”  Many factors can increase the likelihood for injuries or decrease the likelihood.  We can clearly see that the science tells us woman may be more susceptible to injuries and chronic, long term  injuries that may require our long term care.

“With a larger anterior T1 angle, a more lordotic shape with a higher curvature index as well as superior and inferior Bezier angles was found. During impact, normalized ligament stress levels were low for all lower cervical ligaments except the capsular ligaments (CL), which exhibited a peak around the time of the maximum S-Shape.” 

“The majority of both males and females had a mid lordotic cervical spine. To position the model for the validation simulation, the T1 angle was increased to 25°, while the head was allowed to be slightly more forward and rotated upward than specified in the corresponding PMHS study. The initial curvature of the cervical spine has an influence on the segment level kinematics, and on the stress of the CL during impact.” Notice the population they used had lordotic curves? One more example to demonstrate what “normal necks” are closer to, different than what many insurance companies may argue. This study had to increased FHP which can increase cervical loading.

“Sub-catastrophic failure of CL (capsular ligaments) ligaments is one possible cause of long-term WAD which is why a higher ratio of failed elements for the model is likely to correlate with a higher risk for WAD.”  Not a simple “sprain/strain” or “soft tissue” injury is it?? Our treatment can increase CL health. Do you know how?? Join Professionally Integrated for more!!

“Similar to the present work, validated a male head–neck model and studied the influence of cervical curvature, for a lordotic, straight, and kyphotic posture. They reported increased CL elongation for the kyphotic posture in comparison with the lordotic, and concluded that such an abnormal posture can contribute to an increased risk of WAD in a rear impact.”  Things I have been asked in court: “Dr. Katz, how do you know what shape their neck was before the crash?” Me: “I do not for sure. However, they were asymptomatic and most likely asymptomatic individuals have a more “normal shaped neck.”  After the crash they had problems correlated to a loss of curve and other pathologies I documented and explained.  Not to mention, studies show that if they did in fact have a abnormally shaped neck before impact they were more likely to be hurt.”

“In the light of the results of the present study, one can speculate that automotive seat geometry leads to females assuming a cervical spine alignment with more pre-strain of the CL relative to their neutral posture, and this could be a contribution to the higher risk of WAD for females compared with males.” The seats change our posture increasing cervical spine damage.



Join Professionally Integrated today to be the best you can be. 

Journal of Biomechanics 51 (2017) 49–56   Paper here:  follow link: http://www.jbiomech.com/article/S0021-9290(16)31256-8/pdf




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