Joints, Movement and Injuries

What are joints? Joints-places where two bones articulate or come together. The human body contains three types of joints: – Fibrous – Cartilaginous – Synovial

Fibrous Joints Found where bones have close contact with each other. Connective tissue found between the joint Little to no movement Ex. Found between the sutures of the skull

Cartilaginous joints Found where shock absorption occurs. Hyaline cartilage or fibro-cartilage found between the joint. Limited movement, twisting and bending. Found between the vertebrae, sternum to ribs and pubis bone.

Synovial Joints Most of the joints in the skeletal system are synovial joints which allow free movement. Includes hyaline cartilage, connective tissue, synovial membrane and fluid and bursa. Classified into six categories: Ball and Socket, Hinge, Saddle, Condylar (ellipsoid), Pivot and Plane (gliding)

Types of Synovial Joints Based on Shape Slide 5.52a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 5.29a–c

Types of Synovial Joints Based on Shape Slide 5.52b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 5.29d–f

1. Ball-and-Socket joint Ball shaped head of one bone connects to cup-shaped cavity of another. Allows circular motion and motion in all planes. Hip and shoulder

2. Condylar joint (ellipsoid) Oval shaped condyle fits into an elliptical cavity of another. Variety of movements in different planes but not rotational.(twisting) Metacarpals connection with the phalanges.

3. Plane Joints Flat and curved surfaces connect. Allows sliding and gliding motion. Bones of wrist and ankle.

4. Hinge Joint Convex surface of one bone connects to concave surface of another. Movement in one plane. (like a door) Elbow, knee and phalanges.

5. Pivot joint Cylindrical surface of one bone rotates within a ring formed of bone and ligament. Movement around a central axis-rotation. Atlas (the Greek god who supported the world on his shoulders) and axis in cervical vertebrae. Radius/ulna and atlas/axis

6. Saddle joint Connect bones with convex and concave surfaces. Variety of movements in two planes. Bones at carpal and metacarpal of thumb.

Disorders of joints  Injuries  Sprains  Dislocations  Torn cartilage  Inflammatory and degenerative conditions  Bursitis  Tendinitis  Arthritis  Osteoarthritis (“DJD” – degenerative joint disease)  Rheumatoid arthritis (one of many “autoimmune” arthritites)  Gout (crystal arthropathy)  Septic arthritis-bacterial infection