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

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

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

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

Mechanism –Compressive loads –Hyperflexion with lateral bending –nerve root disturbance posterolateral displacement Low Back Pain –85% undiagnosed