Bullet injury with powder tattooing

Three bullet injuries on the left side of the head over the fronto-temporal region



Situated on the left side of the head over the fronto-parietal region are three round bullet injuries with 'powder tatooing'. The sizes approximately range from 5 mm to 8 mm in diameter. The edges show 'abrasion collar' and probably 'ring of dirt' or 'bullet wipe'. There is no evidence of flame burns or 'soot' (blackening). (Ring of dirt is caused by the dirt (grease or oil) on the nose of the bullet. However, it is usually seen around the bullet holes in clothing.)

Powder tattooing are small lacerations caused by gun powder flakes or particles. The soot is produced by the burning of gun powder and its deposition around the entry wound is called 'blackening'. Since it is deposited on the skin unlike Gun powder, which is deposited inside the skin, it can be wiped out easily. The range of soot deposition is around 15 cm in hand guns. (Hand guns are pistols and revolvers. Their muzzle velocity is less than that of rifles. They use smaller cartridges and their barrels are shorter. Therefore, the distance travel by the productions of gun powder burning, such as flame, soot and unburnt, burning and burnt powder, is shorter than that of rifles)

The presence of 'powder tattooing' and absence of 'soot' indicate that this is an 'intermediate range' rifled firearm injury. Probably distance is between 15 - 30 cm since it is more likely to be a hand gun. In fact this man was shot while sitting on the driver's seat of a car through the open shutter.

They are more likely to be hand guns as rifles usually cause much more destructive injuries to the skin and bone in this range. They may cause small lacerations on the edge of the entry wounds and sometimes the entry wound may be 'stellate' or 'cruciate' shape.

They can not be pellet wounds from a shot gun as in this range, which produces 'powder tattooing on the skin', there should be central hole (rat hole) with scalloped edges and satellite pellet injuries and not individual pellet holes. Moreover, the pellets should have been recovered from the skull cavity and they were unlikely to have exited from the skull.

Three round bullet entry holes corresponding to the three entry wounds shown on the above photo with possible inner bevelling. One hole has three radiating fissured fractures.

This is one of the exit wounds of the same case. Note the presence of irregular bone deficiency with external bevelling. This is the hallmark of exit wounds.

This is an exit wound of a bullet injury (not from the same case).

Exit wounds are usually larger than the entry wounds. They can be linear, irregular, or stellate (star like) shape. The bullet which enters the body, looses its kinetic energy after hitting bones and soft tissues. It may give rise to different movements of the bullet. The bullet can tumble and produce a different profile to the skin at the exit e.g. base or side of the body instead of nose. The bullet can also be deformed, which may also contribute to the irregular and larger exit wound.

This is how the 'soft nosed' bullets are deformed.

Bullets are made of lead. Some are fully jacketed, which means the lead core is fully covered with a metal (steel, copper or alloy) sheet. Some are semi-jacketed. Their lead nose is exposed. That's why they are called 'soft nosed' bullet.

Jackets prevent lead being scrapped during its travelling through the gun barrel, which slows down the bullet inside the barrel. Therefore jacketed bullets have much higher muzzle velocity than non-jacketed lead bullets. The disadvantage is that they tend to exit from the body without fully expending its kinetic energy. Whereas the soft nosed bulled is deformed inside the body fully expending the kinetic energy. Therefore, destruction to the target with a deformed bullet is much more than a non-deformed fully jacketed bullet.

Can a forensic pathologist examine the entry wound and tell the police the calibre of the bullet as pathologists do in TV dramas everyday?

No. Due to the elasticity of the skin the diameter of the skin wound is usually smaller than that of the bullet.

Priyanjith Perera

04 November 2012