Download Biomechanics of Joints

Biomechanics of Joints
Articulations
Joint Classifications
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Structural
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Based on anatomical characteristics
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Presence/absence of joint cavity
Type of connective tissue that binds them
Types
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Fibrous joint
Cartilaginous joint
Synovial joint
Joint Classifications
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Functional
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Type of movement they permit
Types
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Synarthrosis-Immoveable joint
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Amphiarthrosis-Slightly moveable joint
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Sutures
Intervertebral joints
Diarthrosis-Freely moveable joint
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Shoulder, knee
Synarthrodial Joint
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Immovable joint
Fibrous joint which can attenuate force with
little or no movement
Examples
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Sutures
Syndesmoses: radioulnar, tibiofibular
Amphiarthrodial Joint
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Cartilagenous joint which attenuates forces
Examples
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Synchondroses: SC Joint
Symphysis: Vertebral Joint, Pubic symphysis
Diarthrodial Joint
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Provides mobility by permitting one body
segment to rotate about another.
Transmits forces from one segment to
another.
Diarthrodial Joint Anatomy
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Articular Cartilage
Articular Capsule
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Fibrous membrane
Synovial membrane
Synovial Fluid
Ligament
Diarthrodial Joint Types
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Hinge Joint
Pivot Joint
Condylar Joint
Ellipsoid Joint
Saddle Joint
Ball and Socket Joint
Flexibility vs. Stability
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Stability: Maintaining Joint integrity
What provides joint stability
Stability vs. Flexibility
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Answer
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Joint construction
Ligaments
Capsule
Tendons
Gravity
Vacuum in joint
Stability vs. Flexibility
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Flexibility: Describes the range of movement
within a joint.
Types:
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AROM
PROM
Question: What factors affect flexibility?
Flexibility vs. Stability
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Answer
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Shape of the articular surface
Muscle mass
Bony blocks
Muscle length/flexibility
Ligament length/flexibility
Age
Question


Describe the range of motion available at the
hip joint before and after a 30-s passive
stretch. Which ROM is greater? Why?
Describe the range of motion available after a
PNF stretch at the hip. Which ROM is
greater? Why?
Levers
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Any elongated, rigid object that rotates
around a fixed pointed called a fulcrum.
Rotation occurs when an effort applied to one
point on the lever overcomes a resistance
located at some other point.
Lever Classes
Levers cont.
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
The function of a lever is to impart an
advantage.
Advantages can be either:


Exert more force against a resisting object than
the force applied to the lever, for example:
moving a boulder with a crowbar.
Move the resisting object farther and faster than
the effort arm is moving.
Classes of Levers
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Determined by which component (fulcrum,
effort, resistance) is in the middle
Class
Orient.
Advantage
Class I:
FAR
Balance
Class II:
ARF
Strength
Class III:
AFR
Speed/ROM