objective 9

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

Objective 9

Compare and contrast the three major categories of joints. Give an example of each.


Joints Articulations of bones Functions of joints

Hold bones together Allow for mobility

Ways joints are classified Functionally Structurally


Functional Classification of Joints Synarthroses – “together joint”

immovable joints, skull

Amphiarthroses – “both side joint” slightly moveable joints, wrist

Diarthroses – “2 (direction) joint” freely moveable joints, all movements


Fibrous Joints Bones united by fibrous tissue Examples

Sutures In skull

Between tibia & fibula

Figure 5.27a–b


Cartilaginous Joints Bones connected by cartilage Examples

Intervertebral joints

Pubic symphysis (pelvis)

Figure 5.27d–e


Synovial Joints Moving bones

separated by a joint cavity

Synovial fluid is found in the joint cavity

Figure 5.24f–h


Objective 10

Name the six types of synovial joints based on the movements they allow.


Features of Synovial Joints Articular cartilage (hyaline cartilage) covers the

ends of bones Joint surfaces are enclosed by a fibrous articular

capsule Have a joint cavity filled with synovial fluid Ligaments reinforce the joint Bursae – flattened fibrous sacs

Lined with synovial membranes Filled with synovial fluid


The Synovial Joint

Figure 5.28


Plane Joint1. Plane joints

Flat surfaces slipping or gliding

movements

Small bones of Wrist & ankle

Figure 8.7a


Types of Synovial Joints2. Hinge joints

Like a hinge on a door, one side fits into the other.

Motion is along a single plane (flex/extend only)

Examples: elbow and interphalangeal joints


Hinge Joints

Figure 8.7b


3. Pivot Joints

Will rotate on an axis

Examples: joint between the axis and the atlas (neck) , and the proximal radioulnar joint (forearm)


Pivot Joints

Figure 8.7c


4. Condyloid or Ellipsoidal Joints Oval surface of one bone fits into a

depression in another

Biaxial joints permit all angular motions

Examples: radiocarpal (wrist) joints, and metacarpophalangeal (knuckle) joints


Condyloid or Ellipsoidal Joints

Figure 8.7d


5. Saddle Joints Each surface has both a concave and a

convex surface

Example: carpometacarpal joint of the thumb


Saddle Joints

Figure 8.7e


6. Ball-and-Socket Joints A bal-like head of one bone articulates with a

cuplike socket of another permit the most free movement

Examples: shoulder and hip joints


Ball-and-Socket Joints

Figure 8.7f

objective 9

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