Current Research Projects

Helical axis of motion of the cervical spine



The helical axis of motion is a 3D analogue to the 2D center of rotation. It is defined as the line about which a rigid body both translates and rotates when it moves with respect to another rigid body. Numerous studies have been undertaken to determine the helical axis of motion of the adult cervical spine. This information is used to understand normal spine biomechanics and injury from trauma like whiplash and to help design orthopaedic or injury prevention devices. No similar data exists for the pediatric population. Understanding the helical axis of motion of a child's head with respect to the torso could play a pivotal role in the design of protective systems, for example child restraints in motor vehicles and safety helmets. Further, the data could be used to improve current designs of pediatric crash test dummies.

The precise location of the helical axis of motion (HAM) of the pediatric cervical spine is calculated in this study. Sixty subjects from the pediatric population (age 4-17 years) perform active flexion/extension, lateral bending and axial rotation motions within their normal range of motion. HAM data of the head with respect to the first thoracic vertebrae is captured using a state-of-the-art optoelectronic motion analysis system (Optotrak Certus Northern Digital Inc., Waterloo ON).

This project is in collaboration with the Injury Biomechanics Laboratory and the Division of Orthopaedic Engineering Research, Departments of Mechanical Engineering and Orthopaedics (Laura L. Greaves, B.A.Sc., Qingan Zhu, Ph.D.) and the Department of Orthopaedics (Angie Perdios, M.Sc., Kishore Mulpuri, M.D., Steven J. Tredwell, M.D) at the University of British Columbia. Synaptic scientists Carolyn Y. Greaves, Mallory E. Cluff and Angela D. Melnyk are centrally involved in this project.