Status of postmortem in Islam

There is an important matter of discussion in Islamic law that postmortem is permissible or not in Islam?so briefly we   can say that if it is inevitable as a need to know the reasons or causes behind the death or murder as supposedly for the legal matter then permissible otherwise not. There is a principal in the Islamic jurisprudence that if we have to face two risks then we choose softer one.In the autopsy important benefit of the human beings attaches by postmortem social life of human beings  may be conserved so to refrain from enormous risk this softer risk may be beare.
لو كان أحدهما أعظم ضررا من الآخر فإن الأشد يزال بالأخف
الأشباه والنظائر ص ١٢٣ج

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