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Joints of the Skeleton

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I). Definition

        Articulations:

            Joints are the weakest part of the skeleton.

II). Classification

A). Functional:

B). Structure:

III) Types of Joints

A). Fibrous:

The amount of movement is based on the length of the tissue fibers.

1). Sutures

suture joint

2). Syndesmoses

syndesmoses joints

 

Limited movement:

 

Considerable movement:

 

3). Gomphoses

Gomphoses Joint

 

B). Cartilaginous Joints

bulletBones are united by cartilage and there is no cavity between the bones.

 

1). Synchondrosis

synchondrosis joints Synchondrosis joint
bullet hyaline cartilage unites the bones at the junction of cartilage

 

2). Symphyses

symphysis joint
bulletCartilage fuses into a pad of fibrocartilage that is compressible and allows some movement.

 C). Synovial Joints

synovial joint

 

bulletArticulating bones are separated by a fluid-containing joint cavity.

IV). Structure of Synovial Joints

structure of synovial joints

A). Articular Cartilage 

 B). Synovial (joint) cavity   

C). Articular Capsule  

D). Synovial Fluid.

E). Reinforcing Ligaments  

F). Fatty Pads or Articular Discs

G). Bursae

bulletFlattened sacs that contain synovial fluid.
bulletFunctions to reduce friction.

H). Tendon Sheath

bulletA bursa that wraps around a tendon that is subject to friction.

 

V). Factors Influencing Joint Stability

A). The shape of articular surfaces.

 

B). Ligaments

 

C). Muscle Tone

 

VI).  Types of Synovial Joints

A). Plane Joints

Plane Joint
bulletFlat articular surfaces 

B). Hinge Joints

hinge joints
bulletCylindrical projections (condyles) fit into concave shapes 

C). Pivot Joints

Pivot Joints
bulletThe rounded end of one bone fits into the sleeve of bone or ligaments 

D). Condyloid or Ellipsoidal Joints

condyloid joints
bulletThe oval surface of one bone fits into the depression of another bone 

E). Saddle Joints

saddle joints
bulletboth concave and convex surfaces that allow for more movement 

F). Ball-and-Socket Joints

ball & socket
bulletSpherical head of bone articulates into a cup like surface of another.

VII).  Examples of Joints

A).  Knees Joint

 

B).  Hip Joint

 

C).  Shoulder Joint

 

D).  Elbow Joint