The project focus has been development of guidelines and methods for upper
extremity injury reduction in car crashes. The safety of the central body parts
improves which indicates the need to develop methods for avoiding non-life
threatening injuries such as fracture of the arms. The purpose of the project was to
study the injury mechanisms for the upper extremity in car crashes, and the aim has
been to propose methods to reduce the injuries. The project focuses on adult
occupants inside the vehicles front seat, and frontal and side impacts. The procedure
began with understanding and identifying the injury mechanisms. Studies show that
most fractures occur on the forearm (radius and ulna) and on the wrists and hands.
To determine which injury mechanisms that were most frequent, data were collected
from 29 computer simulations with 29 different crash scenarios. The most common
kind of impact was the medial part of the wrist in the central part of the instrument
panel, combined with the impact of the elbow in the center consol. The results of the
simulations created a basis for the method of the component test, with focus on the
injury mechanism i.e. the forward movement of the arms into the instrument panel.
The component test consisted of a test rig, on which was mounted with a measuring
arm of a 50th percentile male dummy. The arm dropped into a block of expanded
polypropylene (EPP-block) for observation and study, and with following variable
parameters: the impact angle of the surface, velocity and position of the wrist. Then
also an instrumented measuring arm from a 5th percentile female dummy was
released into an instrument panel.
The project contributes to knowledge about the injury mechanism of the upper
extremity in car crashes. The most frequent injury mechanism is a forward movement
of the arms resulting in an impact with the interior structure of the car. The most
frequent injured region is the distal part of the upper extremity. The project has
developed and suggested the first step to a test method for the specific injury
mechanism. There is a need of more research on how impact angles and velocity
affect the violence on the arm.
2016. , 83 p.
Biomechanics, Upper Extremity Injury Prevention, Fractures, Car Crash, Car Accidents