H. R. Lissner

The Mechanism of Skull Fracture

Deformation patterns of the skull due to blows of low velocity, as well as the mechanism of production of linear skull fracture, have been previously described (1–5). When the dry skull is coated inside and out with “stresscoat” brittle lacquer, and then subjected to a blow, the lacquer cracks in the areas of greatest tensile deformation. The cracks appear on the outside of the skull in the regions in which the bone bends outward and on the internal surface where the bone bends inward. A region of inbending—generally circular, oval, or star-shaped—always surrounds the point of application of a blow, no matter where it is struck. Where the skull curves sharply, however, the extent of the inbending is not so great as in a less curved region. By means of the “stresscoat” technic, it has been shown that outbending of bone may occur at a considerable distance from the point of application of the blow. In some specimens a contrecoup type of outbending has been observed approximately diagonally opposite the poin...

Experimental Concussion: Relation of Acceleration to Physiologic Effect

The general procedure was to anesthetize dogs of various weights with intravenous Nembutal and remove the temporalis muscles bilaterally, thus exposing the skull. The accelerometer used initially in these tests was the unbonded wire type. The range of the accelerometer was + 5 0 G and its natural frequency was 1,600 cycles per second. It weighed 4.3 oz. (figure 1). This accelerometer measured the duration as well as the magnitude of acceleration. In order to eliminate any error produced by the inertia of the instrument and to measure values greater than -1500G, a barium titanate type accelerometer was used (figure 2). This instrument wei hed

Response of the Seated Human Cadaver to Acceleration and Jerk with and without Seat Cushions

Human cadavers were subjected to seat-to-head accelerations to a maximum acceleration and jerk (rate of change of acceleration) of 18 g and 2600 g/sec, respectively, with six different types of seat cushions. Strain gages were cemented to the vertebral column and accelerometers were attached to bone at several levels of the body. The object of the experiments was to observe the effects of varying magnitude of acceleration, jerk, and seat cushions on the strain and acceleration response of the cadaver. Results indicate that dynamic load factor (ratio of peak to mean response) increases with jerk at low jerk levels to a maximum and thereafter remains relatively independent of jerk; increases with mean or terminal acceleration in the range of these tests; and increases for all types of cushions used in these tests. Strains measured on the body of vertebrae, particularly in the lumbar region, correspond closely to body accelerations, but strains measured on the rear of vertebrae were not related to body accelerations.

Radioactive iodinated human serum albumin in the diagnosis of intracranial mass lesions.

RADIOACTIVE iodinated human serum albumin has been used in our laboratory during a period of 18 months from September 1954 to April 1956 as an aid in localizing brain tumors in 116 patients who have had 120 surveys. Of these surveys, 49 were in patients who had a verified brain tumor and 25 in patients who had cerebrovascular disease. In a number of cases the removed tumor was studied for its relative radioactivity. Of the remaining 46 surveys, 19 were performed for headache problems, seven for convulsive disorders, six for degenerative brain disease, five for pseudotumor cerebri, four for post-traumatic complaints following head injury, two for multiple sclerosis, and two for ataxia problems.

THE RESPONSE OF THE HUMAN BODY TO IMPACT

Publisher Summary This chapter discusses the response of the human body to impact. The subject is divided into two major categories, namely, the response of the body to impacts that do not produce injuries and the response when the level of impact is such that injury results. Injury occurs when the ultimate strength of any body tissue is exceeded. In the category where injuries will not occur, tests can be performed on living human volunteers. Mathematical models representing the behavior of the body and its parts may also be devised as the response to impact will probably be fairly linear if the ultimate strength of the tissues is not approached. In the second category, the production of injury will rule out the use of human volunteers as test subjects. It will also eliminate the possibility of producing a simple mathematical model describing the behavior of the body as the tissue response becomes very nonlinear as injury is produced. Test subjects for use in this category have been dummies, human cadavers, and animals. Other significant parameters with regard to the nature of the injury produced are the mass, shape, form, and hardness of the striker. These factors will affect the acceleration and jerk produced and also the time duration of the impact, which is important in the production of injury. In head impact tests of dogs, the duration of the impact was found to be a primary factor in the degree of concussion produced. It must always be kept in mind that impact may produce damage to internal organs, the vascular system, muscles, fascia and tendons, and the body structure of the body, and this damage may occur separately or in combinations.