Life reactions

A forensic term. It refers to various reactions of the body that occur only when the body is alive, and can be divided into systemic and local. Systemic vital reactions are changes that occur throughout the body due to a wound, and generally include anemia, fat embolism, air embolism, parenchymal cell embolism, and blood inhalation. If any of these are present, the wound can be said to have occurred while the body was alive. Local vital reactions are reactive changes that occur at the wound site while the body was alive, and include the following: (1) Epidermal excoriation When there is epidermal excoriation (a wound in which the epidermis has been torn off and the dermis is exposed) in an area without a spot of death, and blood or tissue fluid has coagulated to form a scab, or blood in the capillaries has coagulated to form a net-like structure, or when there is bleeding in the subcutaneous tissue of the denuded area or in the surrounding subcutaneous tissue, it can be said that the wound occurred while the body was alive. (2) Subcutaneous bleeding If there is subcutaneous bleeding in the absence of spots of mortis, the wound was created while the animal was alive. Moreover, in cases where the blood in the tissues was found to be solidly coagulated while in cases where the blood was found to be liquid or lightly coagulated, the wound was created while the animal was alive. When the spots of mortis are severe, the blood in the tissues is easily mistaken for spots of mortis, but when the skin is cut open, solid blood clots are found in the subcutaneous tissues in cases of subcutaneous bleeding, whereas no blood clots are found in cases of spots of mortis. (3) Inflammatory redness, swelling, suppuration, granulation tissue If these findings are present, the wound was clearly created while the animal was alive. Furthermore, wounds created while the animal was alive will open (the wound will open) due to contraction of the skin and muscles, but even if wounds created after death open, the opening will be less severe than those created while the animal was alive. In particular, wounds created after rigor mortis has subsided will not open.

[Tadataka Funao]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

法医学用語。生きているときだけにおこる、さまざまな生体の反応をいい、全身的なものと局所的なものとに分けられる。全身的生活反応とは、創傷によって全身に現れる変化で、一般に貧血、脂肪塞栓(そくせん)、空気塞栓、実質細胞塞栓、血液吸入などがあり、このうちの一つでもあれば、その創傷は生存中に生じたものであるということができる。局所的生活反応とは、生存中に生じた創傷部に現れる反応性変化であって、次のようなものをいう。（1）表皮剥脱(はくだつ)　死斑(しはん)のないところに表皮剥脱（表皮がはぎ取られ、真皮の露出した傷）があって、そこに血液または組織液が凝固して痂皮(かひ)（かさぶた）を形成したり、毛細血管中の血液が凝固して網状を呈しているとき、あるいは、表皮剥脱部の皮下、または周囲の皮下組織に出血があるときには、生存中に生じたものであるということができる。（2）皮下出血　死斑のないところに皮下出血があれば、その創傷は生存中に生じたものである。しかも生存中に生じたものでは組織内に出た血液は固く凝固し、死後に生じたものでは液状をなすか、または軽く凝固している。なお、死斑の強いときには、皮下出血は死斑と誤認しやすいが、皮膚を切ってみると、皮下出血では皮下組織内に固い凝血を認め、死斑では凝血を認めない。（3）炎症性の発赤、腫脹(しゅちょう)、化膿(かのう)、肉芽組織　これらの所見があれば、その創傷は明らかに生前に生じたものである。また、生存中に生じた創傷は、皮膚・筋肉などの収縮によって哆開(しかい)する（傷口が開く）が、死後に生じたものは哆開しても、生前の創傷に比べて軽度である。ことに死体硬直の緩解したあとに生じた創傷は哆開することがない。

［船尾忠孝］

出典　小学館　日本大百科全書(ニッポニカ)日本大百科全書(ニッポニカ)について　情報 | 凡例