Blue colour of bruise is due to
Age of contusion Time since injury Color change First day red(Hb) 2-3 days blue(deoxyHb) 4-5 days bluish black/brown(hemosiderin) 5-6 days greenish(hematoidin) 7-10 days yellow(bilirubin) By 14 days normal Ref: FORENSIC MEDICINE AND TOXICOLOGY DR PC IGNATIUS THIRD EDITION PAGE 118
Hemosiderin
Deoxyhemoglobin
Bilirubin
Hematoidin
Mechanical injuries