Lecture 2: Definitions Flashcards
Biomechanics
application of physics to the understanding of the motions and deformations of body segments, organs, structures, tissues, cells due to forces, pressures, torques, shears, etc
Linked rigid body biomechanics
Rigid bodies are linked at joints
- bones are rigid and muscles deform
Rigid body
mass with a volume
assumption that segments btwn links are rigid = not actually rigid
Advantages/disadvantages for X-Rays with biomecahnics
no error w/ soft tissue motion
drawbacks: exposure to ionizing radiation
- have to time amount of exposure
Skeletal biomechanics
Deformation of the FACIAL SKELETON after getting hit in the face
- facial skeleton deforms a lot (everyday when chewing)
Facial fractures
heal well b/c face is highly vascularized
Vascular biomechanics
Modeling BOTH the DEFORMATION of the wall of a blood vessel and the BLOOD FLOW within the vessel
Cellular biomechanics
Measuring the FORCES with which cells interact w/ their surroundings
Cells can bear and exert force
Assumptions with linked rigid body biomechanics
- Body segments are RIGID
- Segments connect at JOINTS
- Joints have a well-defined number of ‘DEGREES OF FREEDOM’
Degrees of freedom
6 total degrees of freedom (3 linear + 3 rotational)
If there are 6 degrees, 2 rigid bodies are NOT attached
- need to constrain at least one degree of freedom to be attached
Max degrees of freedom is needed for a joint?
Maximum is 5 degrees b/c at least one has to be constrained
Example of joint with 5 degrees of freedom
Temporal mandibular jaw (btwn face and jawline)
- 3 rotational and 2 linear
Degrees of freedom: Hip
Hip has 3 degrees of ROTATIONAL freedom (flex/extend, adduct/abduct, internal/external rotation)
NO linear degrees of freedom
Degrees of freedom: Knee
Knee is a hinge jt. = 1 degree of freedom (ONLY flexion/extension)
doesn’t move in any other degrees (constrained by bony congruents or ligaments)
- linear degrees constrained by ACL/PCL
Applications of linked rigid body mechanics
- coaching
- rehab
- orthopaedic
- ergonomics in workplace
- clothing/fashion
- animation (CGI)