Module 6: Forensic: blunt impact to firearms Flashcards
What are blunt impact injuries?
Rough edges and bridging strands of tissue
- -abrasions: scraping of outer layers of skin
- –contusion: disruption of subcutaneous blood vessels
- -laceration: tearing or rupture of skin by blunt force
- -skeletal fractures
What is a scalp laceration?
Scalp lacerations: important to identify site and number of impacts
–single impact (assault or fall) and many impacts
What is seen in a basal skull fracture?
Raccoon eyes (periorbital contusions), battle sign (Hemorrhage in mastoid process) and blood/CSF rhinorrhea or otorrhea
What are the two different types of intracranial hemorrhage?
Epidural hemorrhage (b/w skull and dura)
–caused by blow to side of head with temporal bone skull fracture and laceration of middle meningeal artery
Subdural hemorrhage (b/w dura and arachnoid )
–due to torn bridging veins with or without fracture
–caused by rapid acceleration or rotational force
What is a focal traumatic brain injury?
Cortical contusions: bruise of the brain (often seen with subarachnoid bruising)
–contrecoup contusion
Cerebral laceration
What is a diffuse traumatic brain injury?
Concussion: transient and highly variable disturbance of neurological function following trauma
–blow to head is not required; pre disposition= APO-E
What is a diffuse traumatic brain injury?
Diffuse axonal injury: rotational acceleration (Shearing of axons as they are stretched beyond elastic point with rotational force)
What are the various types of chest injuries?
Fracture Cardiac contusions and lacerations Aortic Lacerations (deceleration injury and crush injury) Pulmonary contusions and lacerations Diaphragmatic lacerations
What is the sequelae in chest injuries?
Flail chest Hemopericardium Hemothorax SQ emphysema Pneumothorax
In regards to chest injuries what is a deceleration injury?
Heavy heart keeps moving while tethered to vertebrae at distal arch
In regards to chest injuries what is a crush injury?
Osseous pinch (Crushed between chest and spine)
What are examples of abdominal and pelvic injuries?
Liver lacerations
spleen lacerations
mesenteric lacerations
Pelvic fractures
What are examples of extremity injuries?
Soft tissue injury
Long bone fracture
Traumatic amputations
What are pedestrian transportation injuries?
Primary impact with bumper
Secondary impact with windshield (spiderweb pattern of broken glass)
Tertiary impact with roadway
What are the type of occupants in a transportation injury?
Child vs adults Restrained/Unrestrained Type of vehicle (airbag and size) Type of crash (frontal, side, rear, roll over and ejected) Speed
What types of injuries do you see in a head on collision?
Face and head injury, cervical spine injury, braced leg fracture and pelvic fracture
What types of injuries do you see in a rear impact collision?
More neck injury at lower speed
–hyperflexion/extension of neck with cervical spine fractures
What type of injuries do you see in a side impact collision?
Injuries from intrusion and lateral flexion of neck
What type of injuries do you see in a rollover accident?
Unrestrained passengers commonly ejected – amputations and patterned injuries
How would you tell the difference on exam in a fall vs an assault?
Fall: level of hat line, protuberant areas, one plane and contrecup contusions
Assault: above hat line, recessed areas, more than one plane, fracture contusions
What is shaken baby syndrome?
Acceleration and deceleration forces lead to:
- -intracranial injuries
- -retinal hemorrhages
- -long bone fractures
- -posterior rib fractures
What are the clinical feature of shaken baby syndrome?
Mental status changes Increased ICP Resp changes Suggestive bruising Retinal hemorrhage
What is found on clinical and autopsy findings?
Scalp hematomas, subdural, subarachnoid, perioptic nerve and retinal hemorrhages
Who are the perpetrators in shaken baby syndrome?
Biological father BF Female sitter Mother Male Sitter Stepfather
What are common explanations in regards to shaken baby syndrome?
Accidental Injury SODDI No impact/assault Re-bleed of an old subdural hemorrhage Second impact syndrome due to two minor injuries
What are sharp injuries?
Incised (Cuts, slashes) or stab wounds
Sharp injuries are variable in size and shape, what are the various sizes and shapes?
Type of weapon Depth of penetration: wound depth doesnt always match blade length b.c tissue is very compressible Movement of victim.perpetrator Movement of instrument Orientation of body
What are hilt marks?
part of handle of the blade that leaves a mark
What are Langer’s lines?
Lines of elasticity (orientation of collagen fibers in dermis) that determine scarring
- -wound perpendicular to the line: gashing wound
- -used by surgeons for suturing
How can you tell the difference b/t self inflicted an homicide?
Self: history, hesitation marks, not through clothing and rarely head and neck
Homicide: multiple, deep/chops, defense wounds and neck
What are considered small firearms and ammunition?
Handguns
Rifles
Shotguns
Ammunition: bullets, shotgun pellets and shotgun slugs
What are wound ballistics?
Kinetic energy of bullet = weight x velocity2/2g
Temporal and Permanent Cavity:
–tem: shearing, compression and stretching of adjacent tissues as energy is lost from bullet
–perm: actual tract of crush injury by bullet
Density and strength of tissue
Angle of yaw or tumbling at impact
Configuration of bullet
What are the various wound paths?
Perpendicular to skin = concentric abrasion
Angled entry = eccentric abrasion
What is the appearance of an entrance wound?
Ovoid Muzzle abrasion Gunshot residue Marginal abrasion Tissue loss
What is the appearance of an exit wound?
Irregular No muzzle abrasion No gunshot residue No abrasion ring No tissue loss
