A consecutive series of 150 patients with clavicular fractures is presented. In 81% detailed information regarding the mechanism of the injury was available and, of these, 94% had fractured their clavicle from a direct blow on the shoulder; only 6% had fallen on the outstretched hand. This finding, at variance with commonly held views regarding the mechanism of this injury, was further investigated by biomechanical analysis of the forces involved in clavicular fractures. The biomechanical model supported the clinical findings.

Mean platelet volume and count were measured in three groups: patients with acute myocardial infarction, a control group with myocardial ischaemia but no infarction and an asymptomatic group of young males. Mean platelet volume was significantly larger in the myocardial infarction group compared with the ischaemic heart disease group or the asymptomatic group. Two subpopulations were present within the myocardial infarction group. One subgroup had a large mean platelet volume and low count. The other subpopulation was indistinguishable, with regard to platelet count and mean volume, from the ischaemic heart disease group. Over 60% of the myocardial infarction group lay in the area of high platelet volume and low count compared with 13% of the ischaemic heart disease control group and 38% of the asymptomatic group. Acute myocardial infarction is likely to be associated with a large mean platelet volume and low count compared with the ischaemic heart disease group. There is no statistical evidence that this condition is related to smoking or size and site of infarct. This evidence suggests that large mean platelet volume and low platelet count could be a major risk factor for myocardial infarction.

No abstract

The Gorlin equation, which was used to assess the obstruction to flow by a stenosed heart valve, is based on steady flow (time independent) criteria derived from hydraulics. Recently, this equation has been used to obtain an effective orifice area for heart valve substitutes both in vitro and in vivo. In this study, a modification of the original Gorlin equation for use with heart valve substitutes considers both the pulsatility of the valvar flow and possible variations in volumetric flow waveforms induced by differences in myocardial performance. The modified equation also allows for the possibility of regurgitant flows. Its use is illustrated in a study of the hydrodynamic performance of a series of heart valve substitutes and recommendations are made concerning its application to cardiac catheterisation procedures.