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Comparison of World War II Missile Casualty Data
Allan Palmer, M.D.
Detailed reports of missile casualty data obtained during World War II by special wound ballistics teams have already been presented in this volume. (See chapters IV, V, VI, VII, VIII, and IX.) A compilation of these data are presented in the statistical material in this appendix.1 In addition, casualty data from previous wars have also been included as a matter of interest. However, no extensive comparisons have been made between casualties sustained during World War II and those sustained in previous wars because of the difference in weapons employed and of the difference in the medical and surgical eras during which the casualties were sustained.
The percentages in the tables that pertain to the regional distribution of wounds refer to the total number of wounds. In the case of regional frequency, only the frequency with which the various regions of the body are wounded is considered regardless of the number of wounds in each body region. The percentages in the tables which pertain to regional frequency of wounds refer to the number of casualties. From such tabulations, casualties who sustained wounds in more than one region of the body must be excluded or an additional entry made for them.
Table 1 shows the regional distribution of wounds due to all missiles in WIA (wounded-in-action) only, in three wars. The presentation of dissimilar samples is unavoidable since the statistical data have not been collected in a uniform manner. The outstanding difference in wound distribution in the various surveys is the relatively low incidence of chest and abdominal wounds in casualties sustained by the Eighth Air Force bomber crew members wearing body armor.2
There are only two surveys available on regional distribution of wounds in KIA (killed-in-action) casualties where the exact locations of all entry wounds have been recorded. Table 2 shows the regional distribution of the entry wounds due to all missiles in these two studies. Except for the moderately high incidence of chest hits (22.9 percent) in the Fifth U.S. Army dead, the location of hits approaches a random distribution; that is, the percentages of hits in the various regions are proportional to the mean projected areas of the various body regions. The protective effect of body armor in the trunk region, particularly the chest, is again demonstrable in the Eighth Air Force dead as shown by a wound incidence of 20.0 percent (chest and abdomen combined) as compared with 29.4 percent for the Fifth U.S. Army dead.
Table 3 shows the regional frequency of wounds due to all missiles in the killed in action of the Fifth U.S. Army and the Eighth Air Force surveys plus two additional surveys of U.S. battle deaths in the South Pacific Area. The regional frequency is shown by single and multiple regions wounded, and the numbers and the percentages refer to the number of
TABLE 1.-Percent regional distribution of wounds due to all missiles, from casualty samples of wounded in action only, in three wars
1At Dieppe Raid.
TABLE 2.-Regional distribution of wounds due to all missiles in 1,000 Fifth U.S. Army and 164 Eighth Air Force KIA casualties only
casualties. Comparison of tables 2 and 3 shows the striking differences between the regional distribution of wounds and their regional frequency when dealing with samples of killed in action and died of wounds only. It has been observed that the dead are more frequently hit in more than one region of the body than is the case with the wounded. It is of interest to note that the regional frequency of hits in the Fifth U.S. Army casualties approaches more closely that for the Eighth Air Force dead than it does that for the dead that were studied in the Pacific theater. The effect of the wearing of body armor is again apparent in the air force study. The similarity in these two surveys is probably due to the fact that in both of
them the preponderance of missiles causing the casualties were high explosive shell fragments. The incidence of multiple regions hit was at least twice as great in both samples as it was in either of the samples of dead from the Pacific theater. The increased proportion of small arms or "aimed" fire characteristic of the warfare in the Pacific theater accounts for the high incidence of head and trunk wounds in these samples. This is an extreme departure from the randomness of hits as well as from the high incidence of wounds in more than one region of the body characteristic of casualties exposed to shell fragments.
TABLE 3.-Regional frequency of wounds due to all missiles in four samples of battle deaths and KIA casualties
1Includes both KIA casualties and
casualties who died of wounds.
In the consideration of causes of death, a distinction has been made between the causes of death on the one hand and fatal wounds on the other. It was obvious that in many cases more than one wound could have been the cause of death. The following criteria were followed in order to determine the cause of death:3
1. Only the severest one of multiple fatal wounds was regarded as the cause of death in any one casualty.
2. When the severity of a head and a chest or an abdominal wound appeared to be the same, the cause of death was arbitrarily attributed to the head wound.
3. When the severity of a chest and an abdominal wound appeared to be the same, the cause of death was attributed to the chest wound.
4. Decapitations were regarded as causes of death due to wounds in the head and neck region in cases where the head was missing as well as in cases where a head wound was very extensive and associated with complete evulsion of the brain.
5. In the case of extensive mutilating wounds, the cause of death was attributed to a wound of the region of the body nearest the center of the area of mutilation.
Table 4 shows the causes of death in six studies of both military and civilian casualties due to all missiles according to the region of the body in which the primary fatal wound occurred regardless of the region first struck by the missile and regardless of the multiplicity of fatal wounds. Thus, the causes of death in these samples are not more numerous than the number of casualties.
TABLE 4.-Percent distribution of cause of death in military and civilian casualties, by region in which the primary fatal wound occurred
1Killed by bomb splinters during the
"blitz" in 1941.
It may be seen in all of the casualty surveys that wounds of the head and neck region account for the greatest number of fatalities. The chest region is second in all samples except in that of British civilians in London during the "blitz" of 1941. It is possible that the suddenness of wounding by bomb splinters in unarmed and unprotected civilians, in contrast with the military, might account for a greater number of deaths due to abdominal wounds in civilians.
Whether or not there is complete random distribution of wounds in missile casualties can only be ascertained in complete samples of unselected casualties. The sample must include the slightly as well as the severely wounded and the killed. Table 5 shows the relative mean projected surfaces of the various body regions which may be regarded as the relative regional distribution of wounds expected in a sample of casualties exposed to random distribution of the missiles causing wounds. The variations from the expected wound distribution for five samples of casualty data are also shown in table 5. A lower than the expected number of wounds in the chest and the abdomen in the case of the air force casualties was due primarily to the wearing of body armor by aircrew personnel. The higher incidence of head and trunk wounds due to aimed fire or small arms is apparent in the casualties sustained by the ground forces in the Pacific theaters.
Just as in the case of wounded in action only casualty studies, there are only slight and insignificant differences in regional distribution and regional frequency of wounds in complete casualty samples. Table 6 shows the relative regional frequency of wounds due to all missiles in three of the complete casualty surveys previously discussed. The incidence of casualties wounded in more than one region of the body in the three complete casualty samples is fairly constant-ranging as it does from 14.9 to 18.6 percent. By excluding casualties wounded in multiple regions from the data in table 6, the greatest differences between the regional distribution and the regional frequency of wounds would be found in the Eighth Air Force survey. Although 40.4 percent of all wounds occurred in the lower extremities (table 5), if those wounded in multiple regions were excluded from the sample instead of being tabulated in table 6 as "multiple regions," the value of 38.3 percent in table 6 would become 45.0 percent, the difference between regional distribution and regional frequency then being 4.6 percent. Thus, it may be concluded that in an analysis of the regional distribution or frequency of wounds in complete casualty studies the exclusion of those casualties wounded in more than one region of the body does not materially alter the apparent incidence of wounds in the various body regions.
TABLE 5.-Percent regional distribution of wounds due to all missiles, from six surveys of WIA and KIA casualties, by body region
1Percent expected hits.
It has been observed that shell fragments hit the body more at random than the aimed fire of bullets. While initial fragment velocity is often high, the striking velocity is commonly less than that of bullets at battle ranges, due to rapid air retardation. This effect is largely due to sectional density and form factor. It is this fact which makes body armor of value in protecting against fragment injury, while it would appear impractical to contemplate an armor which could materially prevent rifle bullets from causing wounds of the protected areas. Thus, it is proposed that the protective effect of body armor be evaluated on the basis of observed hits on personnel struck by shell fragments only. Ideally, a comparison of the anatomic location of hits on unselected samples of armored and unarmored troops would best reveal the effectiveness of protection. The exact anatomic locations of all hits by high explosive shell fragments on the surface of the body have been accurately recorded in one casualty survey comprised of both the wounded and the killed, that being the 961 Eighth
TABLE 6.-Percent regional frequency of hits due to all missiles, from three surveys of WIA and KIA casualties, by body region
1Percent expected hits.
Air Force flak casualties sustained during June, July, and August 1944 (ch. IX). All of these casualties may be regarded as being "armored." Although the exact incidence of those casualties who were not actually wearing body armor at the time they were wounded or killed is not known, it is known that at least 11 percent were unarmored.
A further evaluation of the protection afforded by body armor may be made from a study of the quantitative relationship (indices of vulnerability) between observed hits and expected hits based upon projected body surface areas. In a relationship of this sort, the nearest approach to random distribution of hits would be expected in a selected sample of casualties due to only fragments from high explosive shells, and the least evidence of randomness would be expected in a selected sample of casualties due only to bullets; that is, "aimed" fire. Since body armor is the subject under discussion, it is felt that selected samples of casualties due to high explosive shell fragments are best suited for this demonstration. Warfare in which bullets cause the majority of casualties would not be the type of warfare in which body armor would be of greatest value. A purely random distribution of hits on unprotected individuals would cause all the indices to be 1.00.
The regional frequency of hits due only to shell fragments in a sample of unarmored ground force troops may be compared with the regional frequency of hits sustained by the armored Eighth Air Force casualties. Table 7 shows the relative regional frequency of hits in the various body regions of the unarmored Bougainville casualties as compared with that of the armored Eighth Air Force casualties.
TABLE 7.-Relative vulnerability of different body regions to shell fragments (multiple wounds excluded) from two surveys of WIA and KIA casualties
1Based on 707 casualties.
The action in which the Fifth U.S. Army in Italy participated and in which at times as many as 85 percent of the casualties were due to shell fragments was the sort of warfare which defensively would be ideally suited to the wearing of body armor by ground force troops. Casualty survey observations on the regional distribution of hits due only to shell fragments in this action, however, were restricted to a sample of KIA only casualties. Table 8 shows for comparison the regional distribution of hits due only to shell fragments and the indices of vulnerability in samples of 850 unarmored Fifth U.S. Army dead and 144 armored Eighth Air Force dead.
It is not fair to attempt to evaluate protection afforded by armor on the basis of observations confined to killed in action only. The chest and abdominal regions are still relatively vital regions of the body even when armored, and the fatalities resulting from fatal wounds in these regions were obviously due to the relatively higher velocity perforating flak fragments which struck these regions in armored aircrew personnel. These fragments approached and
actually may have had velocities which were comparable to the velocities of bullets. A point which may be observed, however, in the two surveys with reference to protection is the difference in the distribution of wounds. The sample of air force dead may be regarded generally as having worn helmets as well as body armor as opposed to the sample of ground force dead which may be regarded generally as having worn helmets but not body armor. Therefore, with greater vital body area coverage by body armor as compared to area of coverage by helmet only, the incidence of head wounds due to shell fragments in air force dead was more than twice that in ground force dead. The low incidence of head wounds due to high explosive shell fragments in the dead of the Fifth U.S. Army was the only instance in all of both the complete and KIA-only casualty surveys studied where the incidence of wounds was less than the projected surface area of that region; that is, less than the expected wound incidence. Figures 1 and 2 show the anatomic location of the hits given in table 8 for the ground force and air force casualties, respectively.
TABLE 8.-Percent regional distribution of wounds and relative vulnerability of body regions to shell fragments, from two casualty surveys of KIA casualties only
1850 casualties with 6,003 wounds.