DiMaio - Blunt trauma wounds Flashcards
5 elements that affect the severity, extent and appearance of blunt trauma injuries
- Amount of force delivered to the body
- Localisation on the body
- Amount of time that the force is delivered
- Nature of the weapon
- Extent of body surface over which the force is delivered
4 mains categories of blunt force injuries
Fracture
Laceration
Abrasion
Contusion
But also:
Avulsion
3 main types of abrasion, with examples for each of them
Patterned (ex: fall on a grill)
Impact (crushing abrasion)
Scrape/brush (ex: road rash)
4 mains stages of healing of abrasions
Scab formation
Epithelial regeneration
Subepithelial granulation and epithelial hyperplasia
Regression of granulation tissue and epithelium
What is a contusion/bruise?
Hemorrhage into soft tissue due to rupture of blood vessels caused by blunt trauma
Name factors that affect the size of a contusion
Age
Sex
Condition of health
Type of tissue struck
2 main types of forces that cause lacerations
Shearing
Crushing
3 elements that allows distinction of a laceration from an incised wound
Irregular borders
Tissue bridges
Abraded or contused borders
Why are there tissue bridges in lacerations?
Different strength of the soft tissue, so blood vessels and nerves resist a higher shearing stress
If a tangential blow causes a laceration, give 2 caracteristics that could help determine the direction of the blow
Undermining of the skin flap on the side of the direction of the blow
Other side (where blow was coming): beveled and abraded
What is an avulsion?
Type of laceration where force is oblique, so ripping of skin and soft tissue
Fractures may be caused by direct or indirect forces. What are the 3 main types of fractures due to direct forces?
Penetrating (gunshot wound): high force, small area
Focal: small force, small area (transverse fracture)
Crush: large force, large area (comminuted)
The bone is weaker to tension or compression forces?
Tension
What are the 2 main types of fractures observed in severe impact injuries?
Tension wedge: blow on a bone, causing tension on the opposite site of impact, then radiate back at 90 degree angle, giving rise to wedge of bone
Oblique
6 types of fractures due to indirect forces
Traction
Angulation
Rotational
Vertical compression
Angulation + compression
Angulation, rotation and compression
What kind of fractures in traction fractures?
Transverse
What kind of fractures in angulation fractures?
Transverse
What kind of fractures in rotational fractures?
Spiral
What are the four categories of pelvic fractures?
Anterior-posterior compression
Lateral compression
Shear
Complex fractures
What kind of fractures in an anterior-posterior compression of pelvis?
Pubic symphysis diastasis + bilateral separation of sacroiliac jointss
What kind of fractures in an lateral compression of pelvis?
Pubic rami fractures
What are the main clinical characteristics of the fat emboli syndrome?
Progressive pulmonary insufficiency
Mental deterioration
Fever
Petechial rash (conjunctivae and chest+ axillae)
+/- tachycardia, thrombocytopenia and renal failure
Main cause of fat emboli
Long bone fracture
But don’t forget soft tissue injury
What distribution and kind of wounds in blunt force defence wound?
Mostly abrasion and contusion, rarely laceration and fracture
Back of the hands
Wrist
Forearms
Arms
What are the main injuries of the head seen in blunt force injuries?
Scalp injuries (laceration, abrasions, contusions)
Fractures
Brain contusion
Subdural hematomas
Epidural hematoma
Intracerebral hemorrhages
What are the 2 main injuries seen in acceleration/decelaration injuries of the head?
Subdural hemomatoma
Diffuse axonal injury
What are the main types of maxillary fratures?
Dentoalveolar
LeFort1
LeFort2
LeFort3
Sagittal
What is a dentoalveolar fracture?
Fragment of maxilla + teeth
What is a LeFort1 fracture?
Transverse fracture of the maxilla, above the apices of the teeth through:
- Nasal septum
- Maxillary sinuses
- Palatine bone
- Sphenoid bone
What is a LeFort2 fracture?
Also known as pyramidal
Same path posteriorly, but curves upward near the zygomatic-maxillary suture, through inferior orbit rim onto the orbital floor, through medial orbital wall and across nasal bones and septum
What is a LeFort3 fracture?
High transverse fracture of the maxilla that goes through the nasofrontal suture, through medial orbital wall and frontozygomatic suture, across the arch and through the sphenoid
Name some factors that affect the generation of a skull fracture
- Amount of hair
- Thickness of the scalp
- Configuration and thickness of the skull
- Elasticity of the bone at the point of impact
- Shape, weight, consistency of the object impacting or impacted by the head
- Velocity at which either the blow was delivered or the head strikes the object
What is the average ft.lb required to cause a simple fracture of the skull?
33.3 to 75 ft.lb
Head weight: between 5 to 11 pounds
X
6 feet tall = 60 ft/lb = enough if fall from height
T or F: there is an absolute correlation between the severity of brain injury and the production of a linear fracture
IT IS NOT ABSOLUTE:
- You can have linear fractures without brain damage
- You can have brain damage without fractures
Characteristics of the velocity and impact surface of a linear skull fracture
Low velocity
Large area of contact between the head and impacting object (ex: fall on pavement)
When you have an impact at low velocity with a large area of contact between the head and impacting object, you have linear fractures. What happens if you have a highest velocity?
Circular fracture around the impact site (extreme inbending at the time of impact)
What are the conditions to cause a depressed skull fracture?
Object with large amount of kinetic energy, but small surface area (ex: hammer blows)
2 impact mechanisms that can cause a type 1 hinge fracture
Tip of the chin
Lateral side of the head
3 impact mechanisms that can cause a ring fracture
Impact on top of the head
Fall on the buttocks
Impact on the chin
Where is the typical location of contrecoup fractures?
Anterior cranial fossa
What are the 2 main divisions of the cervical vertebrae?
C1-C2 (with occiput): bound together by ligamentous bands, no intervertebral disks
C3-C7: presence of intervertebral disks
In what kind of trauma is atlanto-occipital dislocation frequently seen?
Pedestrian struck by MVH or occupants of MVC
What is the main mechanism that cause a fracture of the anterior arch of C1? And lateral bodies? An posterior arch?
Anterior: Hyperextension
Lateral:
Lateral loading
Posterior: hyperextension + axial loading
What are the 5 main types of fractures of the lower cervical spine (C3-C7)
Flexion distraction:
- Disruption of posterior ligament + anterior displacement of a vertebra
Flexion compression:
- Same, but with fracture/compression of a vertebra
Extension distraction:
- anterior disruption at the disc, with posterior displacement of vetebrae
Extension compression:
- Same, but with fracture of the posterior element of the vertebral bodies and increases anterior separation at the disk space
Vertical compression: compression and fracturing of a vertebrae
What is the most frequently encountered traumatic lesion of the brain?
Brain contusions
Which part is the most vulnerable to contusion: sulci or gyrus?
Sulci
What are the main locations of brain contusions?
Frontal lobes (orbital and anterior surface)
Temporal lobes (anterior tip)
What are the 6 types of brain contusions
Coup
Contrecoup
Intermediary coup
Fracture contusion
Gliding contusion
Herniation contusion
T or F: coup contusion are less frequent than contrecoup contusions
True!
What are intermediary coup contusions?
Contusions in the deep structures of the brain (white matter, basal ganglia, copus callosum, brainstem) and along the line of impact
** are said to be seen only in falls
What are gliding contusions?
Hemorrhagic lesions within parasagittal white matter in superior cerebral areas; frequently bilateral
Frequently seen in association of DAI
T or F: brain contusions are more frequent than lacerations in infants?
False!
Mostly lacerations to the white matter
What part of the brainstem is mostly susceptible to lacerations?
Jonction between pons and medulla –> avulsion
Occurs with violent hyperextension of the head and neck
T or F: epidural hematomas are frequent in the elderly population
False: dura is very adherent in elderly people!
What is the main blood vessel that is injured in epidural hematomas?
Meningeal arteries
Mostly the
T or false: a fracture is almost always seen in epidural hematomas
True! 90-95%!
Mostly the squamous portion of the temporal bone
How does death occur in epidural hematomas?
Displacement of the brain with compression of the brainstem
How does the post-mortem fire-related epidural hematoma develops
Shrinking of the dura, with blood exsudation from the dura
T or F: subdural hematoma are often found with skull fractures
False!
Which one is most frequent in falls: DAI or subdural hematoma?
Subdural hematomas
What is the period that distinguished an acute, a subacute and a chronic subdural hematoma?
Acute : < 72h
Subactute: 3 days to 2-3 weeks
Chronic: > 3 weeks
