Chapter 8 - Head Injuries

Greatest danger to our physical well-being due to head structures

controlling life sustaining processes

Head Anatomy

• Skull– 29 bones

• 8 cranial

• 14 facial

• 7 ear

• Hyoid

Head Anatomy

• Brain– Cerebrum

• two hemispheres– Frontal– parietal– temporal– occipital

– Meninges• Dura matter• Arachoid: Sub arachoid

space (CSF)• Pia

Head Anatomy

• Brain stem (relays sensory and motor information and life supporting reflex center, cranial nerves)– Midbrain– Pons– Medulla oblongata

• Cerebellum– Subconscious movements– Equilibrium & posture– Motor error detectors– Movement patterns– Emotional: pleasure & anger

Head Injuries

• Causes– Sudden forces to head

– Direct

– Indirect (inertial)• acceleration &

deceleration mechanism

– Head Motion• translation

• rotation

21%

12%

10%7%

50%

FallsViolenceSportsMisc.Car crash

• Mechanical Properties– Skull: stiff yet compressible– Brain: compliant

• Internal stresses• Strain exceeds capacity to

withstand load• Close vs. Open• Primary and Secondary

– Severity: internal damage to neural structures

• Boxing: CTBE or dementia pugilistica

Head Injuries

Chapter 8 - Trunk Anatomy & Injuries

Largest segment of the body (40-50% body mass).

Trunk Anatomy

• Bone: Axial Skeleton– Ribs

– Sternum

– Vertebrae

Trunk Injuries

• Vertebral fractures– Major Health concern

– Proximity to spinal

– Potential to cause severe neural damage, including death

• Axial compressive loads– T11-L3 minimal curvature,

transition zone

Trunk Injuries

• Three Column model– Burst fracture:

compression force causing vertebrae to shatter from within

– High loading rates: intrusion

– Disk degeneration• Healthy: more intrusion

• Old: less intrusion

Type Anterior Middle Posterior

Compression Compression None None orDistraction

Burst Compression Compression None

Seat-Belt None orcompression

Distraction Distraction

Fracturedislocation

Compressionrotationshear

Distractionrotationshear

Distractionrotationshear

Trunk Injuries

• Spinal Deformities– abnormal distributions

patterns or pathological tissue adaptations

– Associated with cardiopulmonary dysfunction

– Scoliosis: Lateral

Trunk Injuries

• Kyphosis– Sagittal plane:

hunchback– Common in women– Osteoporosis– Prevention: exercise

• Scheuermann’s kyphosis: changes in endplates of growing vertebrae

• Lordosis: abnormal extension (swayback)– Lumbar area

– tilting lumbar area• luumbosacral angle

above 30 deg

Trunk Injuries

• Spondylolysis– defect of the vertebrae

lamina (pars articularis)

• Spondylosthesis– translation or slippage

between adjacent segments

• Five types– Dysplastics– Isthmic– degenerative– Traumatic– Pathological

• Young athletes– Isthmic: repeated

loading of pars region, fractures

Trunk Injuries

• Spondylolisthesis– older: L4-L5

degeneration due to arthritis

– Young: L1-S5, end plate lesions

• Loads of the spinal column– comples

– compression

– torsional - shearing

– tensile - excessive spinal motion

• Lumbar region highest forces

Trunk Injuries

• Disks– viscoelastic– annulus fibrosus

• fibrocartilage• criss-crossed orientation

– nucleus pulposus• 70-90% water• mucoprotein & fibers• intrinsic pressure• High tensile stress

(Poisson’s)

– cartilaginous end plate

Trunk Injuries

Trunk Injuries

• Loading during exercise

• Sit-up versus curls

Trunk Injuries

• Lifting• Weight belts• IAP

Trunk Injuries

• Bulging disks:– nucleus pulposus is

displaced from its normal position

– Rotation stress

Trunk Injuries

Type Description

I Acute back sprain (Injury to soft tissue, ligaments etc)

II Disk fluid ingestion

III Annulus disruption

IV Bulging disk

V Fragments from the nucleus or annulus tear off and move into the joint space

VI Displaced fragment into spinal cord

VII Degeneration of disk

Trunk Injuries

• Mechanism– Compressive loads

– Hyperflexion with lateral bending

– nerve root disturbance• posterolateral

displacement

• Low Back Pain– 85% undiagnosed