1. Bennet I. Omalu, M.D., M.P.H. Forensic Pathologist/ Neuropathologist
THE FORENSIC NEUROPATHOLOGY OF BLUNT FORCE TRAUMA OF THE BRAIN Part 1: An Introduction
Bennet I. Omalu, M.D., M.P.H.
Forensic Pathologist/ Neuropathologist

2. SYNONYMS Brain Trauma Neuro-trauma Traumatic Brain Injury [TBI]
Cranio-Cerebral Injury
Blunt Force Trauma of the Head
TBI causes 44% of traumatic deaths in the US
Blunt force trauma of the brain can be induced by
transference of Kinetic Energy [KE] to the brain by
an un-yielding object or surface with a relatively
broad surface area like a base ball bat or a floor

3. OTHER COMMON MODALITIES OF BRAIN TRAUMA
Penetrating Force Trauma of the Head
E.g.: Stab or incised wounds
Gunshot/ Firearm Wounds of the Head
E.g.: Hand-guns, rifles, shot-guns etc
Asphyxiation [Diffuse Hypoxic-Ischemic Cerebral Injury]
E.g.: Hanging, smothering, Carbon Monoxide intoxication etc
Toxic Injuries e.g. mercury, arsenic, methotrexate
Blunt Force Trauma of the Head is the most prevalent cause of brain injuries

4. BIO-MECHANICAL LOADING [BML]
Mechanism of transference of K.E. to the brain; three major types:
Impact Bio-Mechanical Loading
Transference of energy by direct impact of the head
E.g.: a fall from a height and impact of the head on a floor
E.g.: a base ball bat hitting the head in an assault
Inertial Bio-Mechanical Loading
Transference of energy to the head by acceleration-deceleration shearing forces without impact
E.g.: when a baby is shaken excessively
E.g.: sudden jerk of the head in the elderly without impact
Combined Impact-Inertial Bio-Mechanical Loading

5. BIO-MECHANICAL LOADING [BML]
Angular or rotational acceleration-deceleration is more deleterious to the brain than linear acceleration-deceleration
There is a selective topographic vulnerability of the brain to modalities of bio-mechanical loading
E.g.: the splenium of the corpus callosum is most vulnerable to diffuse shearing of the brain
Impact BML is more likely to generate focal traumatic brain injury
Inertial BML is more likely to generate diffuse traumatic brain injury

6. DEFINITIONS Primary Brain Injury Secondary Brain Injury
Direct and immediate consequence of trauma to the brain e.g. cerebral contusion
Secondary Brain Injury
Indirect and delayed consequence of trauma to the brain e.g. cerebral edema, cerebral herniation
Closed Head Injury
Brain injury with intact dura mater
Open Head Injury
Brain injury with lacerated or disrupted dura mater
Major complications: Streptococcal meningitis and
dural fistula

7. DEFINITIONS Focal Traumatic Brain Injury
Localized injury of the brain e.g. lobar cerebral
contusion, subdural hemorrhage
Diffuse Traumatic Brain Injury
Generalized injury to all regions of the brain e.g.
diffuse shearing of the brain: Diffuse Traumatic
Axonal Injury, Diffuse Hypoxic Injury
Brain Injury Grading: Glasgow Coma Scale
Within 48 hours:
Severe TBI: GCS 1–8
Moderate TBI: GCS 9–12
Mild TBI: GCS 13-15

8. GLASGOW COMA SCALE A minimum score of 3 A maximum score of 15
Best Eye Response. (4)
1. No eye opening.
2. Eye opening to pain.
3. Eye opening to verbal command.
4. Eyes open spontaneously
Best Verbal Response. (5)
1. No verbal response
2. Incomprehensible sounds.
3. Inappropriate words.
4. Confused
5. Orientated
Best Motor Response. (6)
1. No motor response.
2. Extension to pain.
3. Flexion to pain.
4. Withdrawal from pain.
5. Localising pain.
6. Obeys Commands.
A minimum score of 3
A maximum score of 15
Teasdale G., Jennett B., LANCET (ii) 81-83, 1974.

9. MILD TRAUMATIC BRAIN INJURY
Physiological disruption of brain function due to trauma, as manifested by at least one of the following: Any period of loss of consciousness Any loss of memory for events immediately before or after the trauma Any alteration in mental state at the time of the accident (e.g., feeling dazed, disoriented, or confused) Focal neurological deficit(s) that may or may not be transient
But where the severity of the injury does not exceed the
following: a. Post-traumatic amnesia (PTA) not greater than 24 hours
b. After 30 minutes, an initial Glasgow Coma Scale (GCS) of
c. Loss of consciousness of approximately 30 minutes or less

10. MANIFESTATIONS OF BFT OF THE HEAD
Abrasions/ Contusions/ Lacerations of Scalp
Galeal Hemorrhages
Fractures of the skull
Intra-cranial hemorrhages
Cerebral contusions/ lacerations
Congestive brain swelling and cerebral edema
Hypoxic-ischemic brain injury
Traumatic axonal injury
Diffuse vascular injury
Cerebral fat embolism

11. EPIDEMIOLOGY
500, ,000 cases of CNS trauma per year in the U.S.
10% are fatal
% are moderate/ severe
5 - 10% result in residual deficits
150/100,000 population have sequelae of CNS trauma
Leading cause of death in people under 45 years of age
Accounts for 1% of all deaths
Accounts for 30% of deaths from trauma
Accounts for 50% of deaths due to road traffic accidents