Articulations
Chapter 8
Structural Classification of Joints
• Fibrous• no joint cavity, bones held together with collagen fibers
• Cartilagnous• no joint cavity, bones held together with cartilage
• Synovial• have a “synovial” cavity, bones held together with an enclosed capsule & ligaments
Functional Classification of Joints
• Synarthroses (singular = synarthrosis)– Immovable joints
• Amphiarthroses (singular = amphiarthrosis)– Slightly movable joints
• Diarthroses (singular = diarthrosis)– Freely movable joints
Suture: a fibrous synarthrosis
Synchondrosis: a cartilaginous synarthrosis
Syndesmosis: a fibrous amphiarthrosis
An amphiarthrotic synchondrosis
Symphysis: a cartilaginous amphiarthrosis
The shoulder joint
Types of Movements Possible at Synovial Joints
Flexion
Flexion decreases the angle of a joint
Extension
Extension increases the angle of a joint
Extension of the
shoulder
Hyperextension moves a jointbeyond the
usual extended angle
Movements of the neck
Special movement of the ankle
Abduction,Adduction
&Circumduction
Special movements of the antebrachium
Special movements of the foot
You can do this with your hips &
shoulders too!
Also possible with shoulders (but not hips)
Types synovial joints
Hingejoints
These are uniaxial.Examples include the elbow, knee and phalanges.
Pivot
Pivot joints are uniaxial.The proximal radioulnar joint is the best example.
Condyloid joints
Condyloid joints are often biaxial.
Saddle joints
Saddle joints are biaxial.
Ball and Socket
Multiaxial ball & socket joints allow the greatest range of motion.
Structural Details of Some Synovial Joints
Capsule of the
shoulder
Extracapsular ligaments of the hip a.
Extracapsular ligaments of the hip b.
The Elbow reverse view
Anterior view of
the knee
Extracapsular ligaments of
the knee
Common knee injury
ACL replacement
http://www.maitrise-orthop.com/corpusmaitri/orthopaedic/95/plaweski/plaweskius.shtml