patterns of blunt force injury
source: Radiology Assistant (Ledbetter S, Smithius R)
The forensic pathologist must attempt to determine not only what sort of injury one is observing, but interpret what the pattern of injury says regarding the mechanism of injury/ the circumstances of the infliction of those blunt force injuries.
The floowing pages are concerned with the main patterns of blunt force injuries to be recognised:
- falls; and
- blunt force injuries from road traffic collisions.
A victim of assault may present with any combination of injuries, to any part of the body. However, certain patterns of injury may be more consistent with assault than, for example, a simple fall.
In order to exclude assault, one must consider the overall pattern and distribution of injuries, and look specifically for defensive injuries, or marks of restraint, as well as injuries which would be inconsistent with the proposed mechanism of damage.
A patterned injury consistent with a shoe print, may represent the result of a kick, and a curved laceration on the top of the head overlying a depressed curved edged skull fracture may represent the effects of a blow with a hammer, for example.
Injuries are carefully evaluated and documented, and an attempt is made at interpreting their pattern. Body maps can be utilised to demonstrate the distribution of injuries, without the need to show a jury graphic photographs. (See Robinson (2000) for an overview of the examination of victims of assault).
Illustration of the pattern of facial injuries more in keeping with an assault than a fall (bilateral blunt trauma not limited to bony prominences)
This is a faint patterned injury on the face of a child, consisting of bruising and abrasions forming a cross-like shape.
Close to where the child was playing was a shape-sorter toy, with a cross-shaped component (the number 8 piece!).
Simple superimposition of these images (which in forensic casework would be carried out using scaled images of the injury and patterned surface of interest) demonstrates reasonable correspondence between the two. This is an over-simplified example, but demonstrates the principle of patterned injury evaluation in forensic medicine.
Use the superimposition/ overlay tool below to see how the patterned injury evaluation can be undertaken in 'real-time'. (This works best with Firefox and Chrome browsers, but not with Internet Explorer).
(Created using JuxtaposeJS)
violence in comic book art
'the ghostly justice of Lancashire' - the murder of Anna Walker, Blackburne Hundred, Lancashire (1636)
Source: Will Eisner's 'True haunted houses and ghosts Casebook' Ace Books, New York 1976 (via Teachable moments)
kicking, stamping and stomping
Injuries caused by kicking and stamping may result in an abraded surface (which may highlight the pattern of the impacting shoe sole), but if the impact is hard enough to cause a laceration, these patterned features may not be evident. These blows are often centered on the head and side of the face/ neck.
Henn and Lignitz (2004) review the pathological findings in homicidal kicking and 'trampling'. They noted that the head was a 'target of choice', and found characteristic abrasions, lacerations and intradermal bruises mirroring the pattern of the sole of the shoe as well as the contour of the heel (although they do not state the frequency with which these patterned injuries are discenable).
42% of the victims died of blood loss (internal or external), whilst 12.6% died of blood aspiration.
Experimental studies analysing the forces generated by punching and kicking a 'punch-ball' have shown that men could punch with a force of 500 - 850 N and kick to between 750 - 1200 N, whilst women could reach 350 - 550 N and kick to 500 - 750 N. It can be seen that the lowest registered 'power' by kicking and the highest 'power' by punching overlap, and this is independent of gender.
Experimental measurements of the acceleration of a dummy's head kicked on the ground found that the maximum
acceleration achieved was 103 Gy, comparable to the acceleration of the head in a 50 km/h frontal car crash.
3D Imaging of shoe print and injury on skin - Thali et al 2005
murder by blunt force trauma in the news
On 2nd April 2012, a 15-year-old boy was convicted of murdering his mother having struck her head and face approximately 7 times, using a claw hammer. He then attempted to dispose of her body by setting it on fire.
He left a lump hammer close to the body, but the forensic pathologist who examined the body was of the view that this had not caused the injuries, rather a claw hammer had been used.
blunt force trauma pattern references
- Aghayev E, Thali M, Jackowski C et al (2004), 'Virtopsy - Fatal motor vehicle accident with head injury', Journal of Forensic Scences 49(4):
- Atanasijevic TC, Savic SN, Nikolic SD, Djokic VM (2005), 'Frequency and severity of injuries in correlation with the height of fall', Journal of Forensic Sciences 50(3):
- Chao T-C, Lau G, Eng-Swee Teo C (2000), 'Falls from a height: the pathology of trauma from vertical deceleration', Chapter 20 In: Mason JK and Purdue BN, 'The Pathology of Trauma', (3rd Ed) Arnold, London
- Clark JC, Milroy CM (2000), 'Injuries and deaths of pedestrians', Chapter 2 In: Mason J.K, Purdue B.N. ‘The Pathology of Trauma’, 3rd Ed, Arnold, London
- Cordner SM, Ozanne -Smith J (2000), 'Injury and death in the home', Chapter 21 In: Mason J.K, Purdue B.N. ‘The Pathology of Trauma’, 3rd Ed, Arnold, London
- Crass JR, Cohen AM, Motta AO et al (1990), 'A proposed new mechanism of traumatic aortic rupture: the osseous pinch', Radiology 176:645-649
- Henn V, Lignitz E (2004), 'Kicking and trampling to death: pathological features, biomechanical mechanisms, and aspects of victims and perpetrators', Chapter 2 In: Tsokos M (Ed), 'Forensic Pathology Reviews Volume 1', Humana Press Inc, Totowa New Jersey
- Milroy CM, Clark JC (2000), 'Injuries and deaths in vehicle occupants', Chapter 1 In: Mason J.K, Purdue B.N. ‘The Pathology of Trauma’, 3rd Ed, Arnold, London
- Preuß J, Padosch SA, Dettmeyer R et al (2004), 'Injuries in fatal cases of falls downstairs', Forensic Science International 141:121-126
- Robinson S. (2000), ‘The examination of the adult victim of assault’, Chapter 10 In: Mason J.K, Purdue B.N. ‘The Pathology of Trauma’, 3rd Ed, Arnold, London
- Rosenkrantz KM, Sheridan RL (2003), 'Trauma to adult bicyclists: a growing problem in the urban environment', Injury 34:825-829
- Sato Y, Oshima T, Kondo T (2002), 'Airbag injuries: a literature review in consideration of demands in forensic autopsies', Forensic Science International 128:162-167
- Shkrum MJ, McClafferty KJ, Nowak ES, German A (2002), 'Driver and front seat passenger fatalities associated with air bag deployment. Part 2: a review of injury patterns and investigative issues', J Forensic Sci 47(5):
- Spitz W.U. (1993), ‘Blunt force injury’, Chapter 7 in ‘Spitz and Fisher’s Medicolegal investigation of death – Guidelines to the application of pathology to crime investigation’, Spitz W.U. (Ed) 3rd Ed, Charles C Thomas Publishers
- Thali M.J., Braun M., Bruschweiler W., Dirnhofer R. (2000), ‘Matching tire tracks on the head using forensic photogrammetry’, Forensic Science International 113(1-3):281-287
- Thali MJ, Braun M, Aghayev E, Jackowski C, Vock P, Sonnenschein M, Dirnhofer R (2005), 'Virtopsy - scientific documentation, reconstruction and animation in forensic: individual and real 3D data based geo-metric approach including optical body/object surface and radiological CT/MRI scanning', J Forensic Sci 50(2):428-42
- Toro K, Hubay M, Sotonyi P, Keller E (2005), 'Fatal traffic injuries among pedestrians, bicyclists and motor vehicle occupants', Forensic Science International 151(2-3):151-6
- Zivot U, Di Maio VJM (1993), 'Motor vehicle-pedestrian accidents in adults: relationaship between impact speed, injuries and distance thrown', American Journal of Forensic Medicine and Pathology 14:185-186