Wheat Ridge, Colorado RE-EVALUATION OF THE BIOMECHANICS OF BLUNT IMPACT INJURY OF THE HEAD Journal of Surgery, Gynecology, and Obstretics, June 1975, Vol. 140, No. 6
E.S. Gurdjian, M.D., F.A.C.S., and Edwin S. Gurdjian, M.D., Detroit, Michigan
A brief historical review of blunt impact and cerebral concussion is provided. Biomechanical analysis of blunt impact injuries describing the hydrodynamics of coup and contrecoup inertial effects causing cavitation, in bending and high velocity rebound of skull. The vector transmission of forces throughout the cranium as a result of these perameters of physics, including viscosity and density considerations are described.
The anatomophysiological importance of the magnum foramen, biomechanically, is described. The viscoelastic mass properties of the brain are integrated in the description of blunt trauma force propagation to the magnum foramen. The iridite discussion provides description base upon the principals of physics, and trauma imposed upon the brain stem. The foramen magnum is an important anatomic landmark in blunt injuries of the head and permits the development of stress concentration extending toward the craniospinal (brain stem) junction. Pressure gradients and mass motions and their resultant cerebral traumas are defined. The three categories of brain movements during impact are described. Movements of the brain during blunt impact injury are influenced by the magnitude and direction of the applied force, the presence of the foramen magnum, and the elastic deformation of the skull.
Category I involves the inertial forces resulting in coup and contrecoup.
Category II involves the down and up movement of the brain stem and posterior fossa structures that result from the anatomy of the foramen magnum.
Category III is the description of the deformation, elastic deformation, of brain mass resulting in cavitation.
Discussion of brain mass trauma, resulting from mass movement relative to the rough and irregular, bony interior of the cranium, is described. The mechanics of basilar artery entrapment following mid-occipital impact is described. A clear and succinct description of the biomechanics of blunt impact injury is provided.
SYNCOPE, VERTIGO AND DISTURBANCES OF VISION RESULTING FROM INTERMITTENT OBSTRUCTION OF THE VERTEBRAL ARTERIES DUE TO DEFECT IN THE ODONTOID PROCESS AND EXCESSIVE MOBILITY OF THE SECOND CERVICAL VERTEBRA
Frank R. Ford, M.D.
An unusual case history is given. It is that of a young man of 17 years who was subject to attacks of syncope which were followed by nystagmus, diplopia, blurring of vision, and unsteadiness. It was found that the odontoid process was missing and that excessive mobility of the second cervical vertebra was present. Many comprehensive medical evaluation procedures including: reoentgenograms, pneumoencephalograms, electroencephalograms, electrocariograms, carotid sinus reflexes glucose evaluations and arteriograms were performed; all negative. Many medications were administered without result of relief. Chiropractic evaluation revealed a defect of cervical spine. Radiological studies, several, confirmed defect of odontoid process. It was not a result of injury or defect of development. Immobilization of the neck by a plaster cast and later by operative fusion gave complete relief of the symptoms. Evidence is presented to show that displacement of the axis led to transient obstruction of the vertebral arteries and that interruption of the circulation of the brain stem was responsible for the symptoms.
It is suggested that this condition, i.e. obstruction of the vertebral arteries, may occur in cases of fracture of dislocation of the cervical spine.
REFERENCE
Pratt-Thomas, H.R. and Berger, K.E.: Cerebellar and spinal injuries after chiropractic manipulation. J. Am. Med. Assn. 1947, 133:600.
