Anthropometrical analysis of cervical spine injuries

Neck injury mechanisms in train collisions: Dynamic analysis and data mining of the driver impact injury

Human necks are vulnerable in train collision accidents. To design a safer cab workspace, the driver neck injury mechanism should be investigated first. In this study, this issue is addressed by investigating how neck injuries are influenced by the cab workspace dimensions. The driver-console-seat dynamic models are developed to quantify the neck injuries. The three-pivot head-neck-upper torso model is used to evaluate the relative rotation angle between head and upper torso (β+γ). The injury mechanism with the larger (β+γ) value results in more severe neck injuries. The decision tree model is established to explore the most important cab workspace dimensional parameter. The driver submarining posture (the driver exhibits the tendency of sliding down from the seat after contacting the console) generates more (β+γ) value than the flipping over behavior (the driver contacts the console and the upper body continues to move over the top of the console). Four neck injury mechanisms are classified, in which the chest-first impact mechanisms are more dangerous than the knee-first impact mechanisms. The distance between the console edge and knee bolster has the greatest effect on the neck injury. This parameter determines the injury mechanism type as it influences the first contact region of the driver. The distance between the console and seat and the pedal height are the secondary dominant attributes. These three parameters should be considered preferentially for establishing driver protection measures.

Anthropometric assessment of cervical neurovascular structures using CTA to determine zone-specific vulnerability to penetrating fragmentation injuries

AIM

To determine military-specific cervical neurovascular and external anthropometric data to scale future numerical injury models of the neck and improve body armour design with a view to prevention or mitigation of combat neck injury.

MATERIALS AND METHODS

Contrast-enhanced computed tomography (CT) angiograms of 50 UK servicemen were analysed. Mean diameters and distances from the skin surface were determined for the carotid artery (CA), internal jugular vein (IJV), vertebral artery (VA) and spinal cord (SC) at the three surgical neck zones. Horizontal neck circumference at C6 and three potential vertical cervical anthropometric measurements were analysed to determine which had the least variability between subjects.

RESULTS

The diameters of cervical vascular structures are greater and the vessels more superficial as the anatomical plane moves caudally. The SC and VA are better protected than the IJV and CA due to their greater depth and bony coverage, except for the VA in zone 1.

CONCLUSION

Future cervical anthropometric assessments should use the vertical angle of mandible to mid-claviclular distance in combination with the horizontal neck circumference as these demonstrated the least variability. Cervical neurovascular structures are least vulnerable posterosuperiorly and therefore extending the posterior aspect of a ballistic helmet inferiorly or adding a nape protector would appear to be less justified. Cervical vessels are most vulnerable in zone 1 and a circumferential collar of ballistic material at least 75 mm high would cover this area in 95% of this population.

The influence of age, anthropometrics and range of motion on the morphometry of the synovial folds of the lateral atlanto-axial joints: a pilot study

The purpose of this study was to investigate the effect of age, anthropometrics and cervical range of motion upon synovial fold volume. Ten healthy female subjects aged 20-40 years were included in the study. Age, height, body mass, dimensions of the head and neck and cervical range of motion of each subject were measured. Magnetic resonance (MR) images of the cervical spine were acquired; the volume of the ventral and dorsal synovial folds of the right and the left lateral atlanto-axial joints was measured using seed growing and thresholding methods. Using Spearman's correlation coefficient, it was determined that there was no correlation between synovial fold volume and age. Synovial fold volume was positively correlated with subject height and neck length but negatively correlated with body mass, body mass index and the circumference of the head and neck. The relationship between synovial fold volume and range of cervical motion varied with the plane of movement. The ability to image the synovial folds of the lateral atlanto-axial joints using MR imaging to determine their normal morphology provides the basis for investigating synovial fold pathology in patients with neck pain and headache.