Biomechanics in Orthopaedics
Joint Types
Joint Motion
Synovial Joints and
Planes of Motion
Stress Identification
100

The study of external and internal forces that cause motion of the human body is called what?

Biomechanics

100

What is the definition of a joint?

A location in the body where two or more bones meet

100

Describe the movement of hip extension.

Leg swings back behind body

100

Name at least three key structures common to most synovial joints.

Bone, articular cartilage, subchondral bone, synovial membrane, joint capsule, or joint cavity.

100

A truck is towing a car with a rope.  What type of stress is being applied to the rope?

Tension

200

Explain the difference between stress and strain.

Stress – the application of force to an object

Strain – how the object changes (shape or size) in response to stress

200

Name the three main types of joints.

  • Fibrous
  • Cartilaginous
  • Synovial
200

Describe the movement of knee flexion.

Knee bends

200

In which anatomical plane do flexion and extension occur?

Sagittal plane

200

Provide an example of shear stress.

  • Tires skidding on pavement
  • Rubbing hands together
  • Sliding down a playground slide
  • Skiing
300

Describe how a lever, a fulcrum, and an applied force interact.

Lever (bone) is rigid bar that can pivot on a fulcrum (joint) as the result of a force (muscle action).  Sometimes there is resistance (gravity, weight) to that force.

300

Which of the three main types of joints is the most mobile and least stable?

Synovial

300

Describe the movement of shoulder abduction.

Arm moves away from midline of body out to the side

300

Name the type of synovial joint that allows angular movement in a single plane.

Hinge joint (ex: elbow, knee, fingers, toes)

300

A man is wringing out a sponge.  What type of stress is being applied to the sponge?

Torsion

400

Give one reason it is important to understand how bone responds to stress.

  • So that we can take steps to protect and preserve bone (Wolff's law, avoiding injury)
  • So that HCPs can treat bone injuries effectively
  • So that implants can be designed to interact with bone appropriately (encourage in-growth, prevent stress-shielding)
400

True or False:  The skull is an example of a synovial joint.

False (fibrous)

400

Provide an example of adduction.

Part of body (likely leg or arm) moves from the side toward midline of body

400

In which anatomical plane do abduction and adduction occur?

Coronal plane

400

Provide an example of bending.

  • Standing on a diving board
  • Priming an archery bow
  • Sagging floor beam
  • Snapping a pencil
  • Shaping the bill of a ballcap
500

Give one reason it is important to understand how orthopaedic implants respond to stress.

  • So that they can be designed robustly
  • So that they can be implanted in a manner that optimizes performance
500

Name one characteristic of a cartilaginous joint.

  • Slightly moveable
  • Provides some stability and some flexibility
500

What are the two directional terms we use to describe or classify rotation?

Internal and external

500

Describe a ball-and-socket joint and provide one fact about them.

  • Round head of one bone rests in cup-shaped depression of another bone
  • multi-axial, allow greatest range of motion, synovial joint (hip and shoulder are examples)
500

Provide an example of compression.

  • Standing on a soda can
  • Collapsing an accordion
  • A car buckling in a crash
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