Lecture 60 - Biomechanics I Flashcards
What is biomechanics
Study of structure and function of biological systems by method of mechanics
What is kinematics
Description of motion without reference to the cause of the motion
i.e. Displacement, velocity, acceleration
What is kinetics?
Analysis of forces that create motion
i.e. force, torque, pressure, momentum, power
What is linear motion?
Movement of an object in a straight line, at
the same time, in a parallel path (Portions of the
body do not move relative to each other
What is angular motion?
Movement of an object or segment through a fixed axis (Portions of body move at same angle, same time, constant distance from axis)
ex elbow joint moving in flexion and extension
What is curvilinear motion (general motion)?
Combination of linear and angular motion, most common form of motion
of the human body
What is osteokinematics
Study of motions and bones around an axis in reference to sagittal, frontal or transverse planes
Give examples of movements for sagittal, transverse and frontal planes
Sagittal: Flexion/extension (plantar also)
Transverse: MR, LR
Frontal: Side bend, abduction, adduction, ulnar/radial deviation
What is arthrokinematics
Describes the motion that
occurs between articular
surfaces of the two bones of a
joint
What are 3 terms to describe arthrokinematics movement
- Spin
- Glide
- Roll
Describe spin movement
- Twisting action of the bone
- Rotation of the bone around it’s mechanical axis
Describe swing movement
-Describes an “arc of motion”
-Swings within the sagittal or coronal plane
Describe pure vs impure swings
Spin not spine
What is adjunct rotation
rotation which is performed independently about its own axis
* Is a separate degree of freedom of motion (medial, lateral rotation of the knee
in partially flexed knee)
What is conjunct motion
a spin which much accompany a swing as the bone moves
outside the primary plane of motion
* Occurs about the axis of the primary movement (locking and unlocking of the
knee, combined with flexion or extension)
What does concave mean
To bend inwards
What does convex mean
To bend or protrude
What are the 2 types of joint classifications
Anatomical: Based upon anatomical features e.g. synovial vs. non synovial joint
Biomechanical: Categorized for join surface shape which defines degrees of freedom of motion
What are 2 types of anatomical joints and classify them
- Synovial Joint: Freely moveable because bones are separated from one
another. Cavity is filled with lubricant or synovial fluid - Non-Synovial Joints: bones are united by fibrous tissue or cartilage and are
immovable or just slight moveable e.g. structures of the skull, vertebrae
What is an ovoid joint
Ovoid Joint: One surface is convex and the other surface is concave (biomechanical classification)
* E.g. wrist, knuckles, fingers
and toes
* Modified: ellipsoid: (MCP
Joint
- Unmodified: Ball and socket/ Hip and shoulder)
What is a sellar joint
Biomechanical classified joint
Provides flexion, extension, abduction and adduction
Difference between modified and unmodified joints
Unmodified: Standard ovoid shape provides typical ROM for that joint
Modified: Standard ovoid shape but provides rotation on top of typical ROM for that joint
Modified still has same DOF as unmodified even with extra movement
Synovial joint classification table
Explain the concave-convex rule
Image and another explanation of concave convex-rule
What can concave-convex rules be applied to
Joint mobilizations, and proposes that in order to restore rotational motion at a joint, a linear mobilization is performed in relation to the treatment plane
What is the axis of rotation and give the axis of rotation in relation to sagittal, frontal and transverse planes
What is the plane of movement, axis of rotation and direction of movement in this image
Difference between internal and external force
- Internal: Forces that originate
within the body (ex. Muscles) - External: Forces that originate
outside the body (ex. Gravity)
What are force vectors
What causes an MCL/ACL/Medial meniscus tear
Explain an MCL/ACL/Medial meniscus tear in terms of arthrokinematics
- Displacement of femur relative to tibia
- Occult bony lesions occur in 84-98% of
patients with ACL (majority in lateral
compartment) due to translation of
femur - Lateral femoral condyle shifts posteriorly,
and the tibia translates anteriorly and
either internally or externally rotating
YELLOW ARROWS = bone lesion
BLACK ARROWS = disrupted fibers
Explain an MCL/ACL/Medial meniscus tear in terms of kinematics
