A New Neck Injury Criterion in Combined Vertical/Frontal ... · 76 IRCOBI Conference - Madrid (Spain) - September 2006 NECK INJURY CRITERIA: Through the years, several injury criteria

IRCOBI Conference - Madrid (Spain) - September 2006 75

A New Neck Injury Criterion in Combined Vertical/Frontal Crashes

with Head Supported Mass

Cameron R. ‘Dale’ Bass, Lucy Donnellan, Robert Salzar, Scott Lucas, Benny Folk, Martin Davis,

Karin Rafaels, Chris Planchak, Kevin Meyerhoff and Adam Ziemba

University of Virginia – Center for Applied Biomechanics

Nabih Alem

U.S. Army Aeromedical Research Laboratory

ABSTRACT

This study developed a new neck injury risk function suitable for use in frontal crashes with

occupant orientation ranging from predominantly horizontal to predominantly vertical in the occupant

anterior-posterior (A/P) direction. In this study, 36 cadaveric head/neck complexes and 6 whole

cadavers were tested under impact scenarios with varying total head mounted mass and center of

gravity locations. Matched Hybrid III and THOR dummy tests were also performed. The resulting

injury criterion is based on a beam model of the lower cervical spine and is expressed as

YC

Y

ZC

Z

M

M

F

FBC +=

where Fz is the axial compression/tension force, and My is the A/P flexion moment, both at the C7/T1

intervertebral disc. The derived constant values of FZC are 5660 N in axial tension and 5430 N in

axial compression and MYC is 141 N-m in A/P flexion. These values are comparable to single axis

injury tolerance values described in the literature and in existing motor vehicle injury standards for the

upper cervical spine (FMVSS-208, 2003). Beam criterion values (BC) of 1.0 correspond to a 50%

risk of an AIS ≥ 2 injury in the human cervical spine. The THOR dummy was found to reproduce the

kinematics of the cadaver better than did the Hybrid III dummy. However, response curves showed

differences between the THOR and the cadaver that were due to anatomy.

Keywords: NECK, FRONTAL IMPACTS, INJURY CRITERIA, DUMMIES

The introduction of the hard helmet to military aviators in the 1950s helped to protect the head

from impacts (McEntire and Shanahan, 1997). However, the mass of the hard helmet, along with the

additional mass added to the helmet in the form of night vision goggles (NVGs), oxygen masks,

communication devices, and other devices in the 1970s and 1980s, led to neck injuries that were not

seen previously. The cervical spine has to support this additional weight (up to 3.5 kg) along with the

weight of the head, which is approximately 3.5 kg.

The most important injury mechanisms due to head supported mass (HSM) are neck axial tension

and flexion. In general, compression and extension injuries are not seen due to the recent aircraft seat

design requirements that include headrests and load limiting vertical energy absorption capabilities

(McEntire and Shanahan, 1998). Shanahan and Shanahan (1989) found that the level of the C7

vertebra was the most common injury location in helicopter crashes from 1979 to 1985. However,

several of these injuries are believed to be from compression under high vertical impacts in seats not

containing energy absorption capabilities. Further, a series of preliminary sled impact tests performed

by Bass (2002) with Hybrid III dummies in a predominantly vertical orientation showed relatively

large lower neck forces and moments in a common helicopter impact scenario. Based on these

studies, it is expected that the lower cervical spine will be the site of injury during this test series.

Six sled and thirty-six cadaver head-neck component tests were performed for this study. This

study addresses whether Nij, a current neck injury criterion used with crash test dummies, is

applicable to aviation crashes when head supported mass is worn. In addition, a new injury criterion,

the Beam Criterion, was developed specifically for neck injury with added mass based on numerous

cadaveric experiments. Matched Hybrid III and THOR dummy tests were performed to allow

kinematic and dynamic comparison between cadaver and dummy. Finally, full-body cadaver, Hybrid

III, and THOR sled tests were performed to confirm the suitability of component test injury patterns.


NECK INJURY CRITERIA: Through the years, several injury criteria have been developed to

predict neck injuries. These injury criteria are defined for a number of different conditions such as

injury mechanism (e.g., compression, flexion), acceleration environment (e.g., high acceleration,

long-term vibration), and impact condition (e.g., frontal collision, rear collision). Neck injury criteria

have been developed for both minor and serious neck injury.

Simple Loading: Early studies investigated simple loading conditions such as uniaxial force or

single plane bending. Mertz et al. (Mertz and Patrick, 1971, Mertz et al., 1978) defined the limits for

axial compression, flexion, and extension moments using Hybrid III dummy reconstructions of

serious injuries to football players. Two axial compression injury reference values were derived, one

in which the football player is charging a tackling block (6.75 kN) and another in which the player is

stationary (4.0 kN). In addition, Mertz and Patrick performed 90 static and 178 dynamic sled tests on

volunteers and cadavers to determine appropriate flexion and extension injury threshold moment

values. The maximum dynamic moment that the volunteer endured was 88 N-m, which caused a sharp

pain that lasted for several days. When similar tests were run using cadavers under flexion, a value of

190 N-m was determined to be the maximum moment without ligamentous or bony damage, but with

possible muscle damage. During flexion tests, no cadavers were found to have ligamentous or bone

damage. When cadavers underwent extension tests, a 47 N-m torque about the occipital condyles was

non-injurious, while a 57 N-m torque caused ligamentous damage. The flexion and extension critical

values were scaled to a 50th percentile adult male, and are defined as being 190 N-m and 57 N-m,

respectively. The tolerance levels for simple tension and shear loads were developed by Nyquist et

al. (1980) using reconstructions of Swedish field accident data with a Hybrid III dummy in frontal

impact tests. These reconstructions produced a tolerance level of 3300 N in simple tension and 3000

N in simple shear loading in the neck. These simple loading values are the basis for the simple loading

criteria in current Federal Motor Vehicle Safety Standards (FMVSS–208, 2003).

Combined Loading: Since simple loading rarely occurs in automotive and military crashes,

combined loading must be considered. Several injury criteria have been developed for combined

loading that result in either minor injuries or serious injuries. Prasad and Daniels (1984) suggested

that combined forces and moments may cause neck injuries. Cheng et al. (1982) performed

experiments under combined loading by restraining the cadaver’s chest and applying a uniform frontal

restraining load to the chest using an airbag. Four of the six cadavers tested were injured in the upper

neck. After performing cadaver sled tests, Hybrid III tests were performed to determine bending

loads, as well as shear and axial loads. Cheng found a resultant neck force (shear and axial) of 6200 N

for injury. As the test data is left censored, it is likely this represents an upper bound on the force for

fracture occurring at the base of the skull.

Kleinberger et al. (1998) developed that an injury criterion that includes the combined effects of

axial loading and bending moments was necessary and so expanded on the simple loading criteria

defined above. Nij is defined as a linear combination for loads and moments, so that

YC

Y

ZC

Z

M

M

F

FNij += (Equation 1)

where FZ is the axial load in the upper neck, either tension or compression, FZC is the critical axial

load, MY is the moment in the sagittal plane, either flexion or extension, and MYC is the critical

moment. When little or no moment is present, the simple peak tension and compression values serve

as the critical values (Eppinger et al., 2000). Values from the 2000 final rule are shown in Table 1.

These values provide a demarcation for which Nij greater than 1.0; this line corresponds to a 22% risk

of AIS 3+ neck injury.

Dummy Size Tension

(N)

Compression

(N)

Flexion

(N-m)

Extension

(N-m)

50th Percentile Male 6806 6160 310 135

Table 1. Nij intercepts for tension, compression, flexion, and extension (FMVSS – 2003).

Other published injury criteria (c.f. Bostrom et al., 2000, Svensson et al., 1993, Yoganandan et al.,

2002, and Schmitt et al., 2001) are for minor injuries or different injury mechanisms than are expected

in these tests. Nij is potentially the most applicable criterion as it assesses severe injuries based on the

axial force and A/P bending moment in the neck, the expected injury mechanism.


METHODS

Two types of tests were performed in this study. First, sled tests were performed with whole body

cadaveric specimens, a Hybrid III dummy and a THOR dummy. Second, component tests were

performed using head/neck complexes of the three surrogates. Full cadaver tests were performed to

assess injury locations compared with locations found in Shanahan and Shanahan (1989) and to

provide supporting information for component tests. Component tests were performed to assess a

breadth of experimental conditions with more instrumentation than is possible in full sled tests. A

general overview of the test methods is given below.

HEAD SUPPORTED MASS: For all tests, a device based on a cranial fixation halo (PMT, Inc.,

Model 1211-1) was used to allow changes in the center of gravity of the head supported mass in the

coronal plane and a rigid connection to cadaveric specimens. A pair of graphite composite halo rings,

each mounted at 15° from the vertical, was connected by a bridging fixture as shown in Figure 1. This

fixture was positioned on the head of the specimen using sharpened mounting screws to grip the skull

of the specimen. The halo was mounted so that the original center of gravity of the device was located

at the intersection of the Frankfort plane and the mid-coronal plane. The nominal mass of the halo

device was 0.894 kg and the nominal moments of inertia for the halo device alone are Ixx = 10,750 kg-

mm2, Iyy = 6930 kg-mm2, and Izz = 12,400 kg-mm2. Mass was added to the halo device using

cylindrical weights. The center of gravity locations of the head supported mass ranged from 0 mm to

118 mm above the head center of gravity, and the total head supported mass ranged from 2 kg to 4 kg.

Moments of inertia ranged from 13,100 kg-mm2 to 110,000 kg-mm2. Variation in the moment of

inertia of the head supported mass has been shown in calculations to have a limited effect on head

dynamics, while changing the head center of gravity location has a large effect (Bass, 2002).

CADAVERIC SPECIMENS: Cadaveric specimens were procured in accordance with state and

federal regulations and are subject to the oversight of the University of Virginia Cadaver Use

Committee. All cadaveric specimens were fresh frozen with no evidence of wasting disease, Hepatitis

B, Hepatitis C or HIV. The bone quality of each specimen was assessed using a histogram technique

(QBMAP, The IRIS) on pretest CT scans; no specimen had evidence of osteoporosis (T-Score > 2.5

for UCSF 25 year old dataset), preexisting fractures of significant cervical spinal disease that might

compromise skeletal strength. The specimen average mass for component tests was 79±19 kg

compared with a 50th percentile male value of approximately 79 kg, and the average height was

1761±79 mm compared with a 50th percentile male value of approximately 1780 mm. The average age

of the specimens in all component tests was 59 years, and no cadavers tested were older than 74 years.

The specimen average mass for sled tests was 69±26 kg and the average height was 1655±150 mm.

The average age of the specimens was 61 years, and no cadavers tested were older than 70 years.

Detailed specimen anthropometry is shown in Appendix A.

x

z

y

Note: Drawing Not To Scale

Center of

Gravity

15.9 cm

3.8 cm

11.1 cm

11.4 cm

Figure 1. Halo head mounted mass device, front and side view, schematic and coordinate system for

halo head supported mass device.

DUMMIES (HYBRID III AND THOR): Both Hybrid III and THOR-alpha dummies were used for

the component tests and for the sled tests. Hybrid III has a relatively stiff neck that has limited ability

to enter a shearing motion. THOR is an advanced crash test dummy developed by NHTSA and its

collaborators. It has a more compliant neck, which allows for a more biofidelic shearing motion.

Both dummies, however, were designed to simulate human dynamics with musculature for frontal

crashes in an automobile test environment. So, the flexion-tension or flexion-compression loading

condition with head supported mass and a substantial vertical component may be outside the usual

range of application of these dummies.


SLED TEST SETUP: For the full-body validation tests, an acceleration sled system (Via Systems

713) was used with a triangular deceleration pulse based on helicopter crash deceleration time

histories (Alem, 2002) pulse is used with the peak deceleration varying depending on the severity of

injury desired. The carriage test fixture is comprised of several major components, including the seat,

the head support, the universal test fixture (carriage), and the angle support. The seat and head support

fixtures were used in previous small female neck testing (Bolton, 2002), and the geometric angles,

planes, and anchor points were designed to be representative of an aviator seat. Test instrumentation

included six axis head and T6 accelerometer/angular rate sensor packages, sled accelerometers,

acoustic fracture sensors, and seat base load cells as shown in Figure 2. The lumbar region of the seat

back was covered with two inches of foam with a slot cut along the centerline to provide clearance for

instrumentation installed on the spine of the cadaveric subjects. The seatback support was fixed at 300

from the impact vector.

The specimen was initially centered and aligned in the seat. Three one-inch wide nylon straps were

located in the upper torso across the chest, and one strap passed over each shoulder and between the

legs; the restraints were firmly tightened to limit the mobility of the upper torso. For cadaveric tests,

the head was propped to a position similar to that of a Hybrid III dummy using soft viscoelastic foam.

The position of the six axis angular rate sensor/accelerometer package mount was then measured.

For the sled tests, the deceleration profile was triangular in shape, similar to helicopter crash seat

test deceleration profiles. This pulse was selected in consultation with US Army Aeromedical

Research Laboratory (USAARL) personnel (Alem, 2002) and was obtained using a programmable

hydraulic decelerator. The pulse shown is a 30 g deceleration profile. The entering speed and peak

deceleration generally varied throughout the dummy and cadaver sled test series, but the generic

shape of the profiles was similar.

Figure 2. Schematic drawings showing sled cadaver instrumentation.

Six cadaver sled tests were performed to investigate the injuries and kinematics of a specimen in

realistic crash conditions as shown in Table 2. The primary experimental variables in the test series

included the head supported mass at 0, 1.7, and 2 kg, and the impact peak acceleration. Each full-

scale cadaver test held the location of the added mass constant at the head CG, and the seat angle

constant at 30°.

Test Specimen

Added Mass

(kg)

Peak Sled

Decel. (g)

Average

Sled Decel

(g) Δ V (km/hr)

HM3_cad1.905 FRM-204 1.7 33 15.9 47.8

HM3_cad2.908 FRF-215 1.7 25 12.5 43.6

HM3_cad3.974 FRF-195 1.7 15 6.7 33.4

HM3_cad4.975 FRF-194 1.7 15 6.8 34.2

HM3_cad5.976 WMA-217 2.0 17 7.8 36.5

HM3_cad6.977 FRM-193 0.0 17 7.6 36.6

Table 2. Cadaver sled test matrix

COMPONENT TEST SETUP: The specimen head/neck complexes were disarticulated below the

T4 vertebral body. Skin and outer layer musculature were removed from the T1-T4 vertebral bodies

while maintaining ligamentous structure to facilitate potting of the neck and mounting of the sensors

(Figure 3). Screws were implanted into the T4 and T3 vertebral bodies to ensure immobilization of the

T3-T4 spinal segment in the potting fixture, and the spine was oriented in a potting fixture with


normal T4 kyphosis to allow positioning of the specimen in a natural upright posture. The spine was

potted using an epoxy compound (Buehler Inc., Epoxide). Sufficient muscle and other flesh were left

on the T2 vertebral body to enable some flexibility in the T2/T3 spinal segment as the T2 vertebral

body was partially embedded in the epoxy.

The component tests were performed using a pneumatic impactor (Via Systems 928-2). The head-

neck complex was suspended on the underside of the component sled and the lower neck load cell is

placed between the head-neck and the sled. . Depending on test condition, impacts were moderated

using viscoelastic padding or a hydraulic decelerator. To prevent injuries owing to rebound, a

cushioned backstop and hydraulic decelerator were used to decelerate the head. To position the

specimen, the head-neck complex was mounted on the inferior side of the mini-sled. The initial neck

angle measured from the local horizontal (900 from the impact direction) was selected using wedge

fixtures of selected angles as shown in Figure 3b. To position the neck in a natural lordotic posture,

the spines of the cadavers were compressed using frangible tape that held the head in compression

until the time of the test. Once the final position is achieved, the specimen is allowed to relax under

compression for 15 minutes to obtain normal ligamentous response before the test (Lucas et al.,

2005).

a) b)

Load Cell

Potting Cup

45°

Impact

Figure 3. a) Schematic drawing of specimen instrumentation, b) Orientation of test setup – 300

positive

A baseline head mounted mass of 2.0 kg was selected for the impactor dummy and cadaver tests.

The deceleration pulse for the first two series (cad1-cad17, cad36) was designed to be very short to

maximize the shear force in the neck. The remaining tests were performed using a longer duration and

a smaller magnitude pulse. In addition to a variation in acceleration, other variables (initial head-neck

angle, added mass location, and total mass) were tested (Table 3, Table 4). All data was sampled at

10,000 Hz with hardware anti-aliasing at 3300 Hz using an eight-pole Butterworth filter. Series # Cad. Tests Variable Constants

Series I 9 Acceleration Head-Neck Angle, Total Mass, Mass Location (CG)

Series II 9 Head-Neck Angle Total Mass, Mass Location (CG)

Series III 9 Mass Location Head-Neck Angle, Total Mass

Series IV 9 Misc (Total Mass, Angle,

Acceleration)

Table 3. Generic test matrix for cadaver component tests.

RESULTS

INJURY RESULTS: The sled injuries from post-test CT scans and post-test necropsy are shown

in Table 5. Approximately 70% of the component injuries were posterior ligaments, of which 83%

were located between C5 and T2. The predominant injuries were supraspinous ligament and

ligamentum flavum tears and transactions. The component injuries from CT and necropsy for series I,

series II, series III, and series IV are included in Table 6, The injuries from the sled tests have a very

similar pattern. Approximately 67% of the sled injuries were posterior ligaments, of which 79% were

located between C5 and T2.

Approximate maximum AIS (MAIS) values (AAAM, 1998) were assessed for each injury as

shown in Table 6; however, most of the current AIS codes for the cervical spine are related to the

condition of the spinal cord. If the cord is compromised above C3, the threat-to-life is extremely high


(AIS 6); if the cord is compromised below C3, there is a better chance of survival (AIS 4 or 5). An

injury in which the vertebral body is fractured and the ALL ruptured is classified as an AIS 2 or 3

depending on the severity of the fracture. In all cases, the spinal cord was severely autolyzed, so the

spinal cord injury was not easily determined. The spinal cord is especially vulnerable to injury when

the posterior ligaments (e.g., supraspinous ligament, intraspinous ligament, ligamentum flavum) were

torn or transected. If the posterior ligaments were injured in conjunction with the posterior

longitudinal ligament, it was assumed that the spinal cord would be compromised and the

corresponding AIS score was increased.

Mass Position (Relative

to Head cg)

Test Body Number

Added

Mass

(kg) X (cm) Z (cm)

Neck

Angle

(deg)

Maximum Sled

Velocity (m/s)

HM2_cad1 FRM-159 2.0 0 0 0 3.9

HM2_cad2 FRM-141 2.0 0 0 0 5.4

HM2_cad3 FRM-152 2.0 0 0 0 5.4

HM2_cad4 FRM-162 2.0 0 0 0 4.0

HM2_cad5 FRM-158 2.0 0 0 0 4.6

HM2_cad6 FRM-135 2.0 0 0 0 4.0

HM2_cad7 FRM-153 2.0 0 0 0 3.9

HM2_cad8 FRF-214 2.0 0 0 0 4.9

Series I

HM2_cad9 WFA-0155-02 2.0 0 0 0 4.5

HM2_cad10 PMA-0028-04 2.0 0 0 30 2.9

HM2_cad11 PMA-0045-04 2.0 0 0 30 3.7

HM2_cad12 PMA-0027-04 2.0 0 0 30 3.7

HM2_cad13 PMA-0047-04 2.0 0 0 30 3.1

HM2_cad14 PMA-0044-04 2.0 0 0 30 3.7

HM2_cad15 PMA-0046-04 2.0 0 0 30 3.4

HM2_cad16 PMA-0023-04 2.0 0 0 45 1.7

Series II

HM2_cad17 PFA-0029-04 2.0 0 0 15 4.3

HM2_cad18 PMA-0032-04 2.0 0 73 -45 3.7

HM2_cad19 PFA-0051-04 2.0 0 73 -45 3.2

HM2_cad20 PFA-0049-04 2.0 0 73 -45 3.6

HM2_cad21 PMA-0031-04 2.0 0 73 -45 3.8

HM2_cad22 PMA-0053-04 2.0 0 55 -45 3.5

HM2_cad23 2003-FRM-206 2.0 0 32 -45 3.6

HM2_cad24 PMA-0026 2.0 0 32 -45 3.5

HM2_cad25 PMA-0019-04 2.0 0 0 -45 3.5

Series III

HM2_cad26 PMA-0059-04 2.0 0 67 -45 3.6

HM2_cad27 PMA-0055-04 2.0 0 0 -45 3.3

HM2_cad28 PFA-0058-04 2.0 0 55 -45 3.3

HM2_cad29 PFA-0057-04 2.0 0 55 0 3.2

HM2_cad30 PMA-0056-04 2.0 0 73 0 3.2

HM2_cad31 WFA-0224-04 3.0 0 98 0 3.1

HM2_cad32 PMA-0025 3.0 0 98 30 3.2

HM2_cad33 PMA-0063-04 3.0 0 98 30 3.4

HM2_cad34 PMA-0060-04 4.0 0 118 30 3.4

Series IV

HM2_cad35 PFA-0062-04 4.0 0 118 30 3.6

Series II HM2_cad36 PMA-0064-04 2.0 0 0 30 3.3

Table 4. Cadaver component test matrix.

Test Injuries MAIS

Hm3_cad1.905 Ligament tear (ALL) (C3/C4), ligament tears (LF, SSP) (C7/T1), endplate crushing at C7

and T1 (1 cm in width) 3

Hm3_cad2.908 Ligament transection (70-80%) ALL (C2/C3), Disc crushing C2/C3, Osteophyte crushed at

C2/C3 anterior, C7/T1 LF 90% transected, C4/C5 PLL 30% transected 4

Hm3_cad3.974 LF 20% transected C6/C7, LF completely transected C7/T1, ISP transected C7/T1 3

Hm3_cad4.975 SSP and ISP tear C6/C7 2

Hm3_cad5.976 SSP transection C1/C2, ISP tear C1/C2, SSP, ISP, LF transection C5/C6, disc crushed

C5/C6 3

Hm3_cad6.977 Minor damage to intervertebral disc at C6/C7 1

Table 5. Sled cadaver CT and necropsy results.


Test Injuries MAIS

Hm2_cad1 Anterior vertebral body crushing C4-C5, Increased laxity (C4-C5) 2

Hm2_cad2 Lgament transactions (T2-T3) 6

Hm2_cad3 Ligament transactions (C7-T1) 6

Hm2_cad4 Partial ALL ligament tear (C5-C6), minor C5 crushing, C5-C6 IVD damage 3

Hm2_cad5 Ligament tear (C7-T1, ALL), SSP, PLL severely distended, IVD damage (C7-T1) 4

Hm2_cad6 None 0

Hm2_cad7 None 0

Hm2_cad8 Ligament tears (C7-T1) (LF, SSP, ISP), Dens Fracture 4

Hm2_cad9 Ligament tears (C5-C6) (LF, PLL, capsular ligaments) 5

Hm2_cad10 None 0

Hm2_cad11 Ligament tears (C6-C7) (LF, SSP), other ligaments disrupted (C6-C7) 5

Hm2_cad12 Ligament tear (C5-C6) (LF), ALL, PLL permanent deformation (C5-C6),

intervertebral disc damage (C5-C6) 4

Hm2_cad13 None 0

Hm2_cad14 ALL permanent deformation (C6-C7), SSP, ISP excess laxity (C6-C7), LF tear (C5-

C6, C6-C7, C7-T1) 3

Hm2_cad15 ALL tear (C5-C6), associated with osteophyte 2

Hm2_cad16 Fracture of anterior, inferior end plate of C5 0

Hm2_cad17 None 0

Hm2_cad18 Disc tear on posterior side (C3-C4), Capsular ligaments torn (C4-T1) 3

Hm2_cad19 Ligament tear (C4-C6) (LF) 2

Hm2_cad20 None 0

Hm2_cad21 LF and PLL permanent deformation (C4-C6) 1

Hm2_cad22 Ligament tear (C3-C4) (capsular) 2

Hm2_cad23 LF permanent deformation (C5-C7) 1

Hm2_cad24 None 0



Hm2_cad27 None 0

Hm2_cad28 None 0

Hm2_cad29 C1 fracture on the posterior arch 3

Hm2_cad30 None 0

Hm2_cad31 ALL and PLL permanent deformation (C5/C6) 2

Hm2_cad32 None 0

Hm2_cad33 None 0

Hm2_cad34 None 0

Hm2_cad35 None 0

Hm2_cad36 None 0

Table 6. Component cadaver CT and necropsy results.

DUMMY VS. CADAVER KINEMATICS – SLED TESTS: The kinematic responses of cadavers,

the Hybrid III dummy, and the THOR dummy in similar test conditions are remarkably different.

This difference can be compared using high speed video motion analysis. Under shearing motion

characteristic of tension/flexion injuries under inertial loading, the video frame comparison in Figure

4 shows the THOR head performing a motion that appears qualitatively similar to a human-like

frontal S-shaped bending motion before a transition to simple bending shown in Figure 5. In contrast,

the Hybrid III neck rapidly converts shearing motions to simple C-shaped bending modes. Typically,

THOR head center of mass translated about 40 cm in the sled centered frame before reaching joint

stops and flipping into simple flexion, the cadaver translated ~35 cm, and Hybrid III only translated

~10 cm under the conditions tested in this study.

Figure 4. Each subject shown undergoing shearing motions with head supported mass (from left to

right): Hybrid III, cadaver, THOR.


Figure 5. Hybrid III, cadaver, and THOR shown in peak flexion.

Typical head acceleration time histories from similar THOR, Hybrid III and cadaver sled tests are

compared in Figure 6 and Figure 7. Owing to the structural differences between the cadaver and

THOR dummy, the inertial frame head anterior/posterior (A/P) accelerations differ. The THOR

achieves globally similar A/P shearing motion in the head using 1) an extended rotational range of

motion in the OC compared with the Hybrid III, and 2) a local c-shaped mode in the neck. So, the

resulting dynamics of the head center of gravity are different for the THOR and the cadaver. For the

Hybrid III, the impact produces an early acceleration in Z and X demonstrating the lack of a ‘head

lag’ phenomenon seen in cadavers and volunteers (c.f. Thunnissen and Wismans, 1995) For the

cadaver, the neck shearing motion may engage the facet joints, locally stiffening the neck. There is

increased local head A/P acceleration in the cadaver that is not seen in the dummy followed by a

steeper local A/P deceleration. Further, there is more complex dynamics in local A/P head

acceleration in the THOR acceleration. Similar behavior in local head superior/inferior acceleration is

seen in Figure 7. Deceleration in the vertical direction (superiorly) is seen in the cadaver under

shearing motions. From these dynamics, we infer that the neck reaches facet joint stops and acts as a

stiff beam under this loading. Using this inference, when the head reaches limits of rotation about the

C0/C1 joint, head acceleration occurs in the local superior/inferior axis. This behavior is less

pronounced in the THOR dummy and absent in the Hybrid III owing to the lack of free shearing

capability and posterior facet joint support.

Mid torso accelerations (T6) for the THOR and cadaver tests are shown in Figure 8 and Figure 9.

The corresponding Hybrid III tests were not instrumented with the accelerometer package. There is

some evidence that the cadaver package contacted the back support during rotation. However, both

the THOR and the cadaver show local accelerations that are commensurate with the underlying 25 g

sled deceleration time history indicating the desired limitation of motion in the torso from the

restraints.

SENSOR DATA: All data was filtered to SAE J211 standards and was mass compensated, where

appropriate, to account for the mass of the potting cup and tissue between the load cell and the region

of interest (C7-T1). The forces and moments were then transferred from the location of the load cell

to the location of interest (C7-T1) using the dynamics data. Dummy forces and moments were

translated to the OC using standard techniques (e.g. as specified in SAE J1733 (1994) for the Hybrid

III and by GESAC, Inc (Shams, 2004) for the THOR). As the dynamics is constrained to the mid-

sagittal plane, FY, MX, and MZ are small compared to FX, FZ, and MY.

For the cadaver component tests, the peak shear force (FX) peak tensile force (FZ), and peak

flexion moment (MY) are shown in Table 7. By design, the ratio of peak compression force and

tension force (FZ) and A/P bending moment (MY) are altered using impactor force and velocity,

initial head neck angle, position and value of the head supported mass. As shown in Figure 10, Series

I concentrated on large initial shear resulting in low ratios of peak axial force to bending moment.

However, Series II changed neck angle which increased peak axial tension relative to peak flexion

moment. Series III changed the angle and location changing the ratio of compression and tension

relative to the peak flexion moment, and Series IV investigated cross conditions resulting in differing

ratios of peak axial force to peak flexion moments.

DISCUSSION

COMPONENT NIJ CALCULATIONS: To calculate the Nij criterion for neck injury, the axial

force and A/P bending moment measured in the upper neck load cell of the Hybrid III dummy are

used. The intercept values used for the Hybrid III are for the 50th percentile male dummy (Eppinger,

et al.2000). Nij values for Hybrid III tests that are matched tests to cadaver series I (constant neck


angle and added mass with varying acceleration) are presented in Figure 11. It is clear from these

results that the Nij values from these matched Hybrid III tests suggest a lower risk of injury than is

seen in the component tests. Nij is not calculated for the cadaver tests because an upper neck load cell

can not be installed in the upper neck without disrupting the anatomy. However, differences in

kinematics with head supported mass in predominantly frontal/vertical impacts prevent the Hybrid III

from being a suitable assessment tool.

-150

-100

-50

0

50

100

150

0 50 100 150Time (ms)

Cadaver - HM3_cad2.908

Thor - HM5_atd30.962

Hybrid III - HM5_cad49.1048H

ead

X A

cce

lera

tio

n (

g)

Figure 6. Head local (head fixed system) anterioposterior (X) acceleration from cadaver sled test

HM3_cad2.908, THOR test HM5_atd30.962, and Hybrid III test HM3_atd49.104 for similar test

conditions.

-150

-100

-50

0

50

100

150

0 50 100 150Time (ms)



Hybrid III - HM5_atd49.1048

Hea

d Z

Accele

ra

tio

n (

g)

Figure 7. Head local (head fixed system) superioinferior (Z) acceleration from cadaver sled test

HM3_cad2.908, THOR test HM5_atd30.962, and Hybrid III test HM3_atd49.1048 for similar test

conditions.

-100

-50

0

50

100

150

0 50 100 150Time (ms)



Tors

o X

Acc

eler

ati

on

(g)

Figure 8. Torso local (head fixed system) anterioposterior (X) acceleration from cadaver sled test

HM3_cad2.908, THOR Test HM5_atd30.962 for similar test conditions.


-150

-100

-50

0

50

100

150

0 50 100 150Time (ms)



To

rso Z

Acc

eler

ati

on

(g

)

Figure 9. Torso local (head fixed system) superioinferior (Z) acceleration from cadaver sled test

HM3_cad2.908, THOR test HM5_atd30.962 for similar test conditions.

Test Number

Peak Sled

Velocity

(m/s)

Vertical

Distance of

Added Mass to

Head CG (mm)

Added

Mass

(kg)

Initial Head-

Neck Angle

(deg)

Peak

Forward

Shear Force

(N)

Peak

Tensile

Force

(N)

Peak

Flexion

Moment

(N-m)

HM2_cad1 3.9 0 2 0 921 948 76

HM2_cad2 5.4 0 2 0 1145 1319 132

HM2_cad3 5.4 0 2 0 1674 1196 145

HM2_cad4 4.0 0 2 0 1214 1126 134

HM2_cad5 4.6 0 2 0 1667 1834 128

HM2_cad6 4.0 0 2 0 1269 1317 149

HM2_cad7 3.9 0 2 0 1292 1470 106

HM2_cad8 4.9 0 2 0 1167 915 42

HM2_cad9 4.5 0 2 0 2032 1137 108

HM2_cad10 2.9 0 2 30 1292 2638 62

HM2_cad11 3.7 0 2 30 2324 3355 99

HM2_cad12 3.7 0 2 30 2500 3995 95

HM2_cad13 3.1 0 2 30 2310 3843 90

HM2_cad14 3.7 0 2 30 2460 4718 106

HM2_cad15 3.4 0 2 30 1987 3930 115

HM2_cad16 1.7 0 2 45 1504 4217 90

HM2_cad17 3.3 0 2 15 2618 4529 111

HM2_cad36 3.3 0 2 30 2503 2790 126

HM2_cad18 3.7 73 2 -45 1300 880 62

HM2_cad19 3.2 73 2 -45 412 613 57

HM2_cad20 3.6 73 2 -45 751 762 73

HM2_cad21 3.8 73 2 -45 969 579 71

HM2_cad22 3.5 28 2 -45 1310 712 67

HM2_cad23 3.6 32 2 -45 1136 580 63

HM2_cad24 3.5 32 2 -45 1257 847 79

HM2_cad25 3.5 0 2 -45 1542 492 65

HM2_cad26 3.6 67 2 -45 1462 764 114

HM2_cad27 3.3 0 2 -45 339 458 50

HM2_cad28 3.3 28 2 -45 493 587 56

HM2_cad29 3.2 28 2 0 489 545 51

HM2_cad30 3.2 28 2 0 57 496 103

HM2_cad31 3.1 49 3 0 381 560 27

HM2_cad32 3.2 98 3 30 344 1063 25

HM2_cad33 3.4 98 3 30 1371 1802 62

HM2_cad34 3.4 118 4 30 1641 1367 88

HM2_cad35 3.6 118 4 30 1559 1671 75

Table 7. Peak A/P shear, axial force, and flexion moment for cadaver component tests.


0

5

10

15

20

25

30

35

40

45

50

HM

2_cad1

HM

2_cad2

HM

2_cad3

HM

2_cad4

HM

2_cad5

HM

2_cad6

HM

2_cad7

HM

2_cad8

HM

2_cad9

HM

2_cad10

HM

2_cad11

HM

2_cad12

HM

2_cad13

HM

2_cad14

HM

2_cad15

HM

2_cad16

HM

2_cad17

HM

2_cad36

HM

2_cad18

HM

2_cad19

HM

2_cad20

HM

2_cad21

HM

2_cad22

HM

2_cad23

HM

2_cad24

HM

2_cad25

HM

2_cad26

HM

2_cad27

HM

2_cad28

HM

2_cad29

HM

2_cad30

HM

2_cad31

HM

2_cad32

HM

2_cad33

HM

2_cad34

HM

2_cad35

Peak A

xia

l F

orc

e/

Peak F

lexio

n M

om

ent

Compression/Flexion

Tension/Flexion

Series I Series II Series III Series IV

Figure 10. Ratio of peak axial force to peak moment in compression/flexion and tension/flexion.

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

Headmass4_18

- 4.0 m/s

Headmass4_20

- 4.0 m/s

Headmass4_21

- 4.4 m/s

Headmass4_22

- 4.9 m/s

Headmass4_23

- 4.5 m/s

Headmass4_24

- 5.2 m/s

Nij

Figure 11. Hybrid III Series I Nij values. All tests were performed at a zero degree initial head-neck

angle, 2.0 kg HSM mounted at the head CG, and varying peak velocities shown above.

As there are no intercept coefficients currently available for use with the THOR dummy, THOR

Nij calculations used the Hybrid III 50th percentile male values. Nij values for THOR, series I are

presented in Figure 12. As no injury reference values or intercepts are available for THOR, the values

are provided for comparison. However, they are far lower than those for the Hybrid III under

matched conditions for Series I. This suggests that unmodified Nij may not be used with THOR for

impacts with head supported mass.

BEAM CRITERION: Nij is generally seen as a predictor of upper neck injury. In contrast, the

current study saw injuries at the lower neck (C5-T1) in the cadaveric component testing. These

injuries likely arise from the increased moment to the lower neck caused by inertial loading under

head supported mass. This increased moment would not be as pronounced at the upper neck which is

the likely explanation of low injury risk Nij values. To predict injury in the lower neck, a different

approach must be taken. Here, a simple beam criterion based on the stress in a beam (similar to the

concepts behind Nij) is proposed as follows:


)( X

YC

Y

ZC

Z FGM

M

F

FBeam ++= Equation 2

where FZ is the axial load in the neck, either tension or compression, FZC is the critical axial load, MY

is the flexion moment in the sagittal plane, MYC is the critical moment, and G(FX) is some

undetermined function of shear. The Beam Criterion should be evaluated at the intervertebral disk of

C7-T1 to predict injuries occurring about C7-T1 under inertial loading. The criterion is intended to be

evaluated as the maximum of series of instantaneous Beam criteria calculated from the force and

moment time histories.

It is likely that the philosophical basis for this criterion in the lower neck is better than that for the

upper neck since the spinal flexion/extension freedom of motion of the lower neck spinal segments is

less than that of the OC-C1 segment. Further, the addition of a shear force contribution (as yet

undetermined) is based on the observation that simple beam theory does not account for finite

deformation mechanics in the spine. For finite deformations, a portion of the shear force converts to a

normal stress. However, for the neck, this conversion is unknown. When the neck undergoes a shear

force, it forces the ligaments into tension, so some of the shear force must convert to axial force,

which affects the normal stress.

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0.5

Hea

dmas

s4_6

1 - 5

.0 m

/s

Hea

dmas

s4_6

2 - 6

.8 m

/s

Hea

dmas

s4_6

3 - 5

.1 m

/s

Hea

dmas

s4_6

4 - 5

.1 m

/s

Hea

dmas

s4_6

5 - 5

.7 m

/s

Hea

dmas

s4_6

6 - 5

.7 m

/s

Hea

dmas

s4_6

7 - 5

.7 m

/s

Hea

dmas

s4_6

9 - 5

.6 m

/s

Hea

dmas

s4_7

0 - 5

.0 m

/s

Hea

dmas

s4_7

1 - 6

.2 m

/s

Hea

dmas

s4_7

2 - 7

.0 m

/s

Hea

dmas

s4_7

3 - 6

.4 m

/s

Hea

dmas

s4_7

4 - 6

.0 m

/s

Hea

dmas

s4_7

5 - 5

.8 m

/s

Hea

dmas

s4_7

6 - 5

.7 m

/s

Nij

Figure 12. THOR dummy component series I Nij values (All tests at 00 initial head-neck angle, 2.0 kg

HSM mounted at the head CG, and varying peak velocities).

Initially, the Beam Criterion is evaluated without the addition of the shear function, since the shear

conversion to normal stress in the neck is unknown. The critical values chosen as a starting point are

the FMVSS-208 simple bending values. These critical values used are shown in Table 8.

Tension 4170 N

Compression 4000 N

Flexion 190 N-m

Table 8. Initial critical values used for calculating Beam Criterion.

INJURY RISK: A survival analysis (Hosmer, 2003) using the FMVSS-208 critical values was

performed using Minitab version 14 (Minitab, Inc, State College, PA) for injuries of MAIS ≥ 2. A

parametric analysis was performed with arbitrarily censored data using a logistic curve (right censored

for non-injury tests and left censored for injury tests). Maximum likelihood estimates were used in the

calculation of the survival function. The injury risk for a logistic regression is given as

⎥⎦⎤

⎢⎣⎡ −

+=

b

BCaBCRisk

exp1

1)(

Equation 3


where BC is the Beam Criterion value and a and b are the coefficients of the logistic distribution.

Figure 13 shows the injury risk curve generated for BC calculated using FMVSS critical values with a

50% risk of injury at BC = 0.90 and a standard deviation of 0.39.

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2

Beam Criterion

Ris

k o

f In

jury

Injury Risk Curve

95 % Confidence Interval

Injury

No Injury

50 % Injury Risk =

Beam Criteria of

0.9028 ± 0.3883

Figure 13. Beam Criterion injury risk curve using FMVSS critical values.

The failure curve for the Beam Criterion may be optimized to minimize the standard deviation at

the 50% injury risk while constraining the mean BC to be 1.0. The latter satisfies the usual

assumptions for beam failure criteria. To determine these optimal critical values, the ratio between the

tension and flexion critical values was varied. Tension and flexion were chosen because they are the

prominent force/moment mechanisms of injury during this test series. The ratio between compression

and tension forces was chosen to be constant. By changing the ratio of tension force to flexion force,

new injury risk curves may be created with new means and standard deviation values. The standard

deviation values may be minimized using the ratio subject to the constraint that the mean BC is 1.0.

The results of this optimization process for axial force and A/P moment are shown in Table 9. These

values compare well with previous FMVSS-208 intercepts for Nij and single mode injury criteria and

values reported in the literature discussed above. The resulting injury risk curve shown in Figure 14

shows a mean of 1.0 with a standard deviation of 0.38. This satisfies both of the above requirements

of having a low standard deviation and a mean of 1.0.

In addition to the case with no shear presented above, an injury risk curve was developed for BC

with shear in the form:

YC

Y

ZC

ZX

M

M

F

FFBeam +

+=

22*5.0

Equation 4

where FX is the shear force, FZ is the axial load in the neck, either tension or compression, FZC is

critical axial load, MY is the flexion moment in the sagittal plane, and MYC is the critical moment. Fifty

percent of the shear force is added to the axial force. The addition of shear was not found to

significantly impact the predictive nature of the curves. Scaling techniques were also performed using

body mass, vertebral height, vertebral width, and tensile strength (based on age), but were not found

to increase the predictive nature of the curves.

Tension 5660 N

Compression 5430 N

Flexion 141 N-m

Table 9. Optimized critical values for Beam Criterion.


0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2

Beam Criterion

Ris

k o

f In

jury

Injury Risk Curve

95 % Confidence Interval

Injury

No Injury

50 % Injury Risk =

Beam Criteria of

1.0261 ± 0.3761

Figure 14. BC injury risk curve calculated for optimized critical values.

CONCLUSIONS

This study performed a series of tests, including sled tests and head/neck component tests on both

dummy and cadaveric subjects, to assess the risk of neck injury from increased head mounted mass.

Various parameters were investigated including value of head supported mass, the location of the

center of gravity of the head supported mass relative to the head center of mass, the location of the

head supported mass, the severity of impact, and the initial angle of impact.

In testing, injuries were seen that are similar to those seen in impact events with military rotary

wing aircraft with head supported mass under inertial loading. These injuries were located mostly in

the lower cervical spine and were predominantly ligamentous and disk injuries for both sled and

component cadaveric tests.

An injury criterion was developed using cadaveric component head/neck complexes that is based

on a survival analysis with an assumed underlying logistic distribution for dynamic variables

measurable in a dummy and calculable using computational programs. This injury criterion uses a

lower neck beam criterion for the failure stress in a beam (similar to the concepts behind Nij) as

follows:

YC

Y

ZC

Z

M

M

F

FBeam +=

where FZ is the axial load in the neck, either tension or compression, FZC is critical axial load, MY is

the flexion moment in the sagittal plane, and MYC is the critical A/P moment. The Beam Criterion

should be evaluated at the intervertebral disk of C7/T7 to predict injuries occurring about C7/T1 under

inertial loading. Optimized critical values for this criterion derived from minimizing mean error in

the survival analysis are presented in Table 9.

The effect of lower neck anterioposterior shear was found to be low for the test conditions

considered, including high shear conditions. Levels of shear conversion to normal loads to 50% do not

substantially change the survival function above. This may, however, change under conditions in

which lower neck inertial loading is combined with upper neck impact loading. Computational

investigations should be performed to investigate more complex impact conditions. However,

forward A/P shear contributes to a stiffening of the cadaveric necks substantially affecting dynamics.

The existing Nij criteria evaluated at the upper neck were not found to be adequate for use for the

neck injury with head supported mass under inertial loading. There are two reasons for this.


1. The Nij criteria are based on the Hybrid III dummy. However, the Hybrid III dummy is

not generally adequate for simulating human motions under purely inertial flexion/tension

loading. In such loading, the dummy shows no humanlike lag of head rotation with neck

rotation. The effect of this is exacerbated by head supported mass under inertial loading.

The testing emphasized the limited biofidelity of the Hybrid III neck, both from a joint

torque basis and for structural biofidelity. The structure of the neck, with a heavy central

cable and high bending stiffness, produced lower neck loads and moments that are

substantially higher than those from the upper neck used in the current injury criterion. The

increased compliance of the human neck would likely not produce such loads and moment in

realistic circumstances with realistic phasing. Further, there is a potential for increasing lower

neck loads through muscular interactions. However, that will not produce a pure moment

about the joint center, but will produce enhanced neck tension and shear forces. The effect of

neck tensioning in pilots during impacts is unknown, but should be investigated.

2. Upper neck flexion moment is generally lower than lower neck flexion moment under the

conditions investigated. This emphasizes the importance of the moment arm of the head and

head supported mass system in the dummy response. The effect of this moment arm is

exacerbated by head supported mass. The differences between the dynamic behavior of

cadavers and the THOR dummy in sled testing emphasize differences in moment/angle

properties and anatomy between humans and THOR. Though THOR kinematics is improved

over the Hybrid III dummy, there is a limited representation of the inferred effect of facet

joint stops in forward shear under inertial loading. In the human response, this likely

contributes to a substantial stiffening of the neck under A/P shear with the head forward of

the lower neck, engaging the cervical facets.

The gross kinematics of the Hybrid III was found to be different from that of the cadavers in sled

testing, while the THOR dummy was found to have similar kinematics to the cadavers in sled testing.

THOR was found to have different dynamic behavior than the cadaveric specimens, however, in

complex s-shaped bending as the THOR-alpha neck does not represent shear motion joint stop (facet

joints) behavior inferred from cadaveric specimen dynamics. Owing to similarities in structural

response, this may also be true for the THOR-NT and THOR-FT necks.

There are several limitations of this study. Cadaveric response may be different than human

response under active and passive muscle control; the cadaver is neither a tensed nor a relaxed human.

However, during the impact event (~80 ms), there is not sufficient time for voluntary muscular action.

So, active pretensioning, passive musculature, and reflex responses remain. However, there are limits

to the influence of muscle response beyond pre-positioning during an impact, and to a certain extent,

the positioning effects of passive and active musculature may be simulated as done in these

experiments. In addition, the dummies used in this study were designed for automobile impacts in a

seated posture. Further, the intent of the dummies is to include the muscle response of humans which

is not reproduced in cadaveric specimens.

ACKNOWLEDGEMENTS

The authors gratefully acknowledge support from the U.S. Army Aeromedical Research

Laboratory, the U.S. Army Office of Scientific Research, the Battelle Memorial Foundation and the

UVa School of Engineering and Applied Sciences for this study.

REFERENCES

AAAM (1998)The Abbreviated Injury Scale, 1998 Update. Association for the Advancement of

Automotive Medicine.

Alem, N. (2002) personal communication.

Bass, C.R. (2002) Impact and Head Supported Mass. Report Headmass1. University of Virginia,

Center for Applied Biomechanics, Charlottesville, VA.

Bolton, J. (2002) Horizontal Decelerator Ejection Seat Testing Using a Hybrid III Test Dummy and a

Human Surrogate. Final Report to Naval Air Warfare Center. University of Virginia, Automobile

Safety Laboratory, Charlottesville, VA.

Bostrom, O., Bohman, K., Haland, Y., and Kullgren, A. (2000) New AIS1 Long-Term Neck Injury

Criteria Candidates Based on Real Frontal Crash Analysis, IRCOBI.


Cheng, R., Yang, K., Levine, R., King, A. and Morgan, R. (1982) Injuries to the Cervical Spine

Caused by a Distributed Frontal Load to the Chest. In Proceedings of the 26th Stapp Car Crash

Conference, pages 1-40. Society of Automotive Engineers, 1982. SAE Paper Number 821155.

Eppinger, R., Sun, E., Kuppa, S., and Saul, R. (2000) Supplement: Development of Improved Injury

Criteria for the Assessment of Advanced Automotive Restraint Systems - II. NHTSA, Washington,

DC.

US-DOT (2003) Federal motor vehicle safety standards, FMVSS-208, U.S. Department of

Transportation, Washington, DC.

Hosmer, D, and Lemeshow, S., Applied Survival Analysis, John Wiley and Sons, NY, 2003.

Lucas, S., Bass, C.R., Salzar, R., Planchak, C., and Ziemba, A. (2005) Material Properties and Failure

Characteristics of Cervical Spinal Ligaments under High-Rate Loading, Aerospace Medical

Association Conference, Kansas City, MO.

Kleinberger, M., Sun, E., Eppinger, R., Kuppa, S., and Saul, R. (1998) Development of Improved

Injury Criteria for the Assessment of Advanced Automotive Restraint Systems. NHTSA,

Washington, DC.

McEntire, B.J., and Shanahan, D.F. (1997) Mass Requirements for Helicopter Aircrew Helmets.

USAARL Report Number AD-A328597.

McEntire, B.J., and Shanahan, D.F. (1998) Mass Requirements for Helicopter Aircrew Helmets.

USAARL Report Number 98-14, 1998.

Mertz , H. and Patrick, L. (1971) Strength and Response of the Human Neck.” 15th Stapp Car Crash

Conference, pages 2903-2928, Society of Automotive Engineers, SAE paper number 710855.

Mertz, H., Hodgson, V., Thomas, L.M., and Nyquist, G. (1978) An Assessment of Compressive Neck

Loads Under Injury Producing Conditions.” The Physician and Sports Medicine, pages 95-106.

Mertz, H., Prasad, P., and Irwin, A. (1997) Injury Risk Curves for Children and Adults in Frontal and

Rear Collisions. In Proceedings of the 41st Stapp Car Crash Conference. Society of Automotive

Engineers, SAE Paper Number 973318.

Nightingale RW, et al. (1997) The Dynamic Responses of the Cervical Spine: Buckling, End

Conditions, and Tolerance in Compression Impacts. Proceedings of the Forty-First Stapp Car Crash

Conference, SAE Paper No. 973344, pp. 451-471.

Nyquist, G., Begman, P., King, A., and Mertz, H. (1980) Correlation of Field Injuries and GM Hybrid

III Dummy Responses for Lap-Should Belt Restraint. Journal of Biomechanics, vol. 102, pp. 103-

109, 1980.

Prasad, P., and Daniel, R. (1984) A Biomechanical Analysis of Head, Neck and Torso Injuries to

Child Surrogates Due to Sudden Torso Acceleration, Stapp Car Crash Conference, Paper Number

841656.

SAE (1994) Sign Convention for Vehicle Crash Testing – SAE J1733, in 2000 SAE Handbook,

Society of Automotive Engineers, Warrendale, PA.

Schmitt, K.U., Muser, M.H., and Niederer. P. (2001) A New Neck Injury Criterion Candidate for Rear

End Collisions Taking Into Account Shear Forces and Bending Moments. In Proceedings of the

17th ESV Conference, Amsterdam, The Netherlands..

Shams, T. (2003) Personal Communication.

Shanahan, D.F and Shanahan, M.O. (1998) Injury in US Army helicopter crashes fiscal years October

1979 – September 1985. Journal of Trauma. 29(4):415-423.

Svensson, M., Aldman, B., Hansson, H., Lovsund, P., Seeman, T., Suneson, A., and Ortengren, T.

(1993) Pressure Effects in the Spinal Canal During Whiplash Motion – A Possible Cause of Injury

to the Cervical Spinal Ganglia. In International IRCOBI Conference on the Biomechanics of

Impacts, pages 189-200.

Thunnissen, J., and Wismans, J. (1995) Human Volunteer Head-Neck Response in Frontal Flexion: A

New Analysis, Proceedings of the 39th Stapp Carr Crash Conference, Society of Automotive

Engineers, Warrendale, PA.

Yoganandan, N., Pintar, F. and Cusick, J. (2002) Biomechanical Analyses of Whiplash Injuries Using

an Experimental Model. Accident Analysis & Prevention. 34:663-671.


Appendix A – Specimen Anthropometry

Test Specimen Sex Age Mass

(kg)

Stature

(mm)

Cause of Death

HM3_cad1.905 FRM-204 M 60 89 1702 Throat Cancer

HM3_cad2.908 FRM-215 M 70 105 1854 Cardiac Arrest

HM3_cad4.974 FRF-195 F 67 54 1685 Lung Cancer

HM3_cad5.975 FRF-194 F 38 95 1630 Sepsis, Cardiac Arrest

HM3_cad6.976 WMA-217 M 64 93 1780 Myocardial Infarction

HM3_cad7.977 FRM-193 M 53 87 1790 Cirrhosis of Liver

Table 10: Anthropometry – sled tests.

Test Specimen Sex Age Mass

(kg)

Height

(mm)

Cause of Death

HM2_cad1 FRM-159 M 66 66 1680 Prostate cancer

HM2_cad2 FRM-141 M 65 78 1780 Cardiac arrest

HM2_cad3 FRM-152 M 70 80 1780 Emphysema

HM2_cad4 FRM-162 M 43 114 1880 Cardiomyopathy, dysrhythmia

HM2_cad5 FRM-158 M 65 90 1800 Lung abscess

HM2_cad6 FRM-135 M 65 78 1780 Ventricular fibrillation

HM2_cad7 FRM-153 M 60 105 1750 Brain cancer

HM2_cad8 FRF-214 F 42 55 1765 Suicide

Series I

HM2_cad9 WFA-155 F 71 54 1650 Myocardial infarction

HM2_cad10 PMA-028 M 64 61 1727 Liver, lung cancer

HM2_cad11 PMA-045 M 68 79 1880 Renal failure, MI

HM2_cad12 PMA-027 M 68 91 1829 Lung cancer

HM2_cad13 PMA-047 M 61 91 1880 Pulmonary disease

HM2_cad14 PMA-044 M 71 64 1753 Heart disease

HM2_cad15 PMA-046 M 64 661 1702 Stroke, pneumonia

HM2_cad16 PMA-023 M 42 79 1803 Pulmonary edema, dysrhythmia

Series II

HM2_cad17 PFA-029 F 61 68 1676 Breast/brain cancer

HM2_cad18 PMA-032 M 49 57 1753 Metastatic lung cancer

HM2_cad19 PFA-051 F 63 77 1854 Lung cancer

HM2_cad20 PFA-049 F 59 118 1600 Myocardial infarction

HM2_cad21 PMA-031 M 70 59 1727 Liver failure

HM2_cad22 PMA-053 M 60 100 1778 Pneumonia

HM2_cad23 WMA-206 M 47 48 1705 Alchoholism

HM2_cad24 PMA-026 M 23 92 1829 Leukemia - schizophrenia

HM2_cad25 PMA-019 M 68 73 1880 NA

Series III

HM2_cad26 PMA-059 M 53 104 1905 Myocardial infarction

HM2_cad27 PMA-055 M 43 73 1702 Cancer

HM2_cad28 PFA-058 F 64 120 1651 COPD

HM2_cad29 PFA-057 F 69 88 1753 Myocardial infarction

HM2_cad30 PMA-056 M 57 85 1753 Cardiac arrest

HM2_cad31 WFA-0224 F 74 64 1730 Cardiovascular accident

HM2_cad32 PMA-025 M 48 50 1617 Acute leukemia

HM2_cad33 PMA-063 M 44 66 1753 Colon cancer

HM2_cad34 PMA-060 M 71 73 1727 Glioblastoma

Series IV

HM2_cad35 PFA-062 F 50 661 17002 Heart failure

SeriesII HM2_cad36 PMA-064 M 55 95 1880 Cardiac arrest

Table 11: Anthropometry – component tests.

1 Estimated from subject stature using regression from current dataset 2 Estimated from C5 length correlation with stature from current dataset.

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A New Neck Injury Criterion in Combined Vertical/Frontal ... · 76 IRCOBI Conference - Madrid (Spain) - September 2006 NECK INJURY CRITERIA: Through the years, several injury criteria