FIREARMS - الأعيرة النارية

Firearm Chapter
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Mechanism of firing
Rifling marks
Pattern of firearm


Firearm Injuries
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Estimation of the distance of firing (firearm) & Estimation of the period of survival (infanticide)


Estimation of the distance of firing (firearm)

1) Effect of hot explosive gases (causing inlet to be irregular, lacerated, everted & larger than exit):
- max distance 15 cm.

2) Effect of flame & smoke (burning & blackening around inlet):
- 1:1.5 times the barrel.
- long weapons >> 1 m. smokeless poweder & 1.5 m. black powder.
- short weapons >> 25 cm.

3) Effect of powder particles (blackening & tattooing around inlet):
- 2:3 times the barrel.
- long weapons >> 2 m. smokeless powder & 3 m. black powder.
- short weapons >> 50 cm.
ضعف اللي قبلها

4) Dispersion of shots (non-rifled):
(ch = central hole, dis = dispersion)
- ch only >> less than 1 m.
- ch + dis 2 cm >> 1 m.
- ch + dis 4 cm >> 2 m.
- ch + dis 9 cm >> 3 m.
- full dis 16 cm >> 4 m.
- dis 25 cm >> 5 m.
- dis 32 cm >> 6 m.
- dis 50 cm >> 8 m.
- dis covers whole body >> 20 m.
- no penetration >> 50 m.
no ch starting from 4m. distance
from 2m.:5m. dispersion equals the square of the distance

5) The wads (non-rifled):
- external wad >> penetration (up to 1 m.) & circular abrasion (1:3 m.)
- internal wad >> penetration (up to 3 m.) & circular abrasion (3:10 m.)
external - internal
1 - (3) -10
pen. - (abr. pen.) - abr.

6) Power of penetration of bullets.

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Estimation of the period of survival (infanticide)





1) Desquamation of the skin & its extent: (22)
- starts 2 d. after birth & completed after 2 w.

2) Floatation of the stomach & intestines: (036)
- stomach only >> indication of respiration = live-birth.
- stomach + duodenum + upper intestine only >> lived 3 h.
- all parts >> lived at least 6 h.

3) Changes in the skin at the base of the umbilical cord: (1212)
- ring of hypermia >> 1 d.
- ulceration of ring starts >> 2 d.
- fall of umbilical stump >> 1 w.
- formation of umbilicus >> 2w.

4) Changes in the umbilical vessels: (2121)
- shrunken vessels + red blood clot in lumen >> 1:2 d.
- starting organization >> 1 w.
- complete organization >> 2 w.
- vessels change into fibrous cord >> 4 w. = 1 month

So in umbilical cord:
- skin (1212).
- vessels (2121).

5) Obliteration of the ductus arteriosus:
(66) (6 is the mirror image of d in ductus)
- functional closure >> 6 h.
- actual obliteration >> 6 w.

6) Closure of foramen ovale: 1 w. (sometimes doesn't close causing persistent patent valvular foramen).

7) AM injuries & vital reactions (healing & sepsis): denotes live-birth.