EXAM SUN/SAT (6-7)

What causes more brain injury?

Vehicular crashes result in more brain injuries than any other cause.

Two broad categories based on the mechanism by which the injury is produced

impact injuries, Acceleration/ deceleration

Acceleration and deceleration injuries are?

caused by sudden movement of the head immediately after injury, with the resultant production of intracranial pressure gradients and subjecting of the brain to both shearing and tensile force

Injuries from impact tramuas?

Soft tissue: lacerations, abrasions, and contusions of the scalp

o Fracture of the skull

o Contusions of the brain

o Epidural hematomas

o Intracerebral hemorrhage

Skull fractures depend upon?

o The thickness of the scalp, amount of hair

o The configuration and thickness of the skull

o The elasticity of the bone at the point of impact

o The shape, weight and consistency of the object impacting or impacted by the head

o The velocity at which either the blow was delivered, or the head strikes the obje

Diffuse Axonal Injuries:

Shearing of the axons results in the breaking of the nerve connections

Subdural Hematomas:

The most common lethal injury associated with head trauma

Injuries produced by Acceleration or Deceleration Trauma:

• Subdural hematomas

• Diffuse axonal injury.

Epidural Hematomas

Primary impact injuries. Always a coup injury; never a contrecoup.

Relatively infrequent

ex: falls and accidents by vehicle; present at the point of impact.

o The bleeding usually produces a disk shape and originates from the rupture of an artery.

o Symptoms usually occur 4–8 hours after the injury.

Contrecoup Contusions:

 Occur in areas of the brain directly opposite to the point of impact due to tensile force

injuries caused by the brain rebounding backward from the skull following impact. (fall)

Coup Contusions

: Occur at the site of the impact and result from the inbending bone

snapping back causing tensile force injuries to the brain. Coup contusions are less common than contrecoup contusions

Costusions of the Brain?

o 1. Coup Contusions

o 2. Contrecoup Contusions

o 3. Fracture Contusions

o 4. Intermediary Coup Contusions

o 5. Gliding Contusions

o 6. Herniation Contusion

Basilar Skull Fractures?

Occur to the base of the skull. Maybe hinge fractures that completely bisect the base of the skull, creating a “hinge

Depressed Skull Fracture:

 Occurs when the skull is struck with an object having a relatively large amount of kinetic energy but a small surface area

impacts only a small area of the skull. Example: Hammer strike to the head

 No linear fractures radiate from the circular depression in the scalp

Simple Linear Fractures:

 Seen in low-velocity impacts with a large area of contact between the head and the impacting object. Example: Fall to pavement.

 Production of a single linear fracture requires approximately 33.3 to 75 ft-lbs of energy.

Is there a correlation between the severity of a brain injury and the production of a linear skull fracture?

There is no correlation between the severity of brain injury and the production of a linear skull fracture.

Skull fracture means?

the degree of deformation and the extent of any fractures is dependent

upon

Subdural hematomas

(Under the dura) - Secondary to tearing of the subdural bridging

veins

Diffuse axonal injury?

secondary to the injury of axons

Can skull fractures occur without a detectable brain injury? And can death without a skull fracture happen?

Yes, Skull fractures can occur without any detectable brain injury

Yes, death may result from extensive brain injury without a skull fracture

Four Types of Wounds Caused by Pointed and Sharp-Edged Weapons:

1. Stab Wounds

2. Incised Wounds

3. Chop Wounds

4. Therapeutic/diagnostic wounds

STAB WOUNDS:

 Produced by pointed instruments.

 Most are homicidal.

 The depth of the wound into the body is greater than its length on the skin surface.

 Edges of the wound are sharp, without abrasion or contusion.

 Never to be confused with a laceration

The sharper, needle like the instrument is the more readily?

it will perforate the skin.

Knife Anatomy?

Look at image

Stab Wounds: What is true about the width and length of a knife?

 The length of the wound on the skin surface can be equal to, less than or greater

than the width of the knife.

 The depth of the stab wound can be equal to, less than, or greater than the length

of the knife blade.

Stab Wound Appearance is Dependent upon

nature of the stabbing instrument

– Sharpness of weapon will determine appearance of the wound margins

 direction of the thrust

 movement of the blade in the wound

 movement of the individual stabbed

 state of relaxation or tension of the skin

 Langer’s Lines

– “A pattern of elastic fibers in the dermis of the skin, which is

approximately the same from individual to individual.” (Text, p. 190)

Stab wounds perpendicular to the fibers

will produce gapping wounds.

Stab wounds parallel to the fibers will produce

“narrow slit-like wounds”

What are langer's lines?

A pattern of elastic fibers in the dermis of the skin which is approximately the same from individual to individual

a blow with an axe causes a _______ cut with fine abrasion of the wound edges due to the ________ of the blade

sharp & heaviness

The length and depth of the incised wound _________ yield information about then weapon

will not yield information about the weapon

What are cut or incised wounds?

C- produced by sharp-edged weapons or instruments

IW- weapon drawn over the skin with sufficient pressure to produce an injury that is longer than it is deep