Penetrating gunshots to the head and lack of immediate incapacitation II. Review of case reports

Abstract

Because of the enhanced intracranial tissue disruption (see companion paper) and the functional significance of the central nervous system, penetrating gunshot wounds of the head commonly result in immediate incapacitation. However, in the last century numerous publications reported sustained capability to act following penetrating gunshot wounds of the head. These are reviewed. A large number of case reports had to be excluded from re-examination because of doubtful capability to act or lack of morphological documentation. There remained 53 case reports from 42 sources for systematic analysis. Favourable conditions for sustained capability to act are present in cases where the additional wounding resulting from the special wound ballistic qualities of the head (see companion paper) are minimized. Thus, more than 70% of the guns used fired slow and lightweight bullets: 6.35 mm Browning, .22 rimfire or extremely ineffective projectiles (ancient, inappropriate or selfmade). A centre-fire rifle or a shotgun from close range were never employed in cases involving intracerebral tracts. A coincidence of several lucky circumstances made sustained capability to act possible in two cases of military centrefire rifle bullets passing longitudinally between the frontal lobes without direct contact with brain tissue. Only two large handguns resulting in intracerebral wounding were used: one firing a .38 special bullet, which solely wounded the base of the right temporal lobe and one firing a .45 lead bullet, which seriously injured the left frontal lobe but whose trajectory was limited to the anterior fossa of the skull. Of the trajectories, 28% were outside the neurocranium. At least 70% of the craniocerebral tracts passed above the anterior fossa of the skull, wounding the frontal parts of the brain. Apart from a neurophysiological approach, this preference can be explained by the fact that the base of the anterior cranial fossa and the sella turcica area serve as a bony barrier protecting the parts of the brain located in its "shadow"' relative to the trajectory against cavitational tissue displacement and associated overpressures. This is particularly true of the brain stem. Intracerebral trajectories not located above the anterior fossa were caused by slow and lightweight bullets preferring one temporal lobe. Additionally, one parietal and one occipital lobe were each injured once by a very ineffective projectile and by a 7.65-mm bullet reduced in velocity. Not a single case of injury to the brain stem, the diencephalon, the cerebellum or major paths of motor conduction and only one grazing shot of the anterior parts of the nucleus caudatus (basal ganglia) were described. Morphological signs of high intracranial pressure peaks (cortical contusion zones, indirect skull fractures, perivascular haemorrhages) and secondary missiles were poorly documented. It is suggested that these findings are at least very rare and not obvious in cases of sustained capability to act.

Wounding capacity of muzzle-gas pressure

“…Of course, the additional wounding capacity of muzzle-gas pressure depends on the load of the cartridge. Karger [19] published a review of suicidal gunshot wounds to the head where a lack of incapacitation was observed, especially concerning cartridges of low-gas pressure with .22, .25 or .32 calibres. Still, there are cases of successful suicides with blank cartridge guns pressed against the head [20].…”

Expression of fibronectin suicidal in gunshot wounds

“…turcica, where significant amount of energy has been absorbed [6,7]. The variation between scores is due to the simple fact that this type of study cannot be carried out in controlled laboratory conditions.…”

“…rifles). However, death in cases of low energy projectile can be instantaneous, if the vital structures of the brain stem are damaged [6,7].…”

Suicídio atípico com dois ou mais disparos efetivos de arma de fogo: casuística do Instituto Médico Legal de Belo Horizonte e implicações periciais

“…Lesões de órgãos torácicos produzidas por projéteis de uso civil, mesmo considerando a transfixação do coração, da porção torácica da artéria aorta ou do tronco pulmonar, normalmente não causam parada circulatória imediata, ainda que sejam lesões que produzirão incapacitação e que serão geralmente fatais [6,[23][24][25]. Ou seja, ao contrário do "senso comum" e do que é representado em filmes e seriados de televisão, uma lesão cardíaca transfixante por projétil de arma de fogo (PAF) de uso civil ainda permite que a vítima execute movimentos por um período mínimo de 10 segundos, o suficiente para efetuar um ou mais disparos com uma AF [6,[24][25].…”

“…Fisiologicamente, apenas lesões no sistema nervoso central (SNC) causam incapacidade motora imediata, desde que envolvam regiões encefálicas específicas, como a porção cervical alta da medula espinal, o tronco encefálico (mesencéfalo, ponte ou bulbo), o diencéfalo e áreas extensas do córtex cerebral [6,[23][24][25]. Ressalta-se que lesões dessas regiões mais nobres do SNC também podem ocorrer sem que o projétil as atinja diretamente, através da transmissão radial de energia produzida pela cavitação temporária dos projéteis [30].…”