Review

Sutures (Fibrous Joints) These can be found connecting the plates of the skull. As the plates fuse in the adult, the sutures are called synostoses and result in immovable joints.

Gomphotic Joints (Fibrous Joints) These are a peg and socket joint. The only example is the articulation of the tooth and its socket.

Figure 8.3 General structure of a synovial joint. Periosteum Ligament Fibrous capsule Synovial membrane Joint cavity (contains synovial fluid) Articular (hyaline) cartilage Articular

Associated Structures Other structures commonly associated with synovial joints include fat pads and articular discs of fibrocartilage. They work like “ball bearings” and reduce friction where ligaments, tendons and muscles rub against each other.

Associated Structures Tendon Sheaths Bursae of the knee

Figure 8.7b Types of synovial joints. Hinge joint (elbow joint) a c d e f Nonaxial Uniaxial Biaxial Multiaxial

The Knee The menisci help prevent lateral motion and attach to the outer margins of the joint capsule on the tibia. They are easily torn.

The synovial cavity of the knee has a complicated shape and over one dozen associated bursae. Some are easily injured such as the subcutaneous prepatellar bursa which lies just over the patella (house maid’s knee).

Two additional ligaments, the Fibular and Tibial Collateral Ligaments prevent lateral or medial rotation when the knee is extended.

Knee Injuries Common knee injuries involve the 3 C’s: Collateral ligaments, Cruciate ligaments and Cartilage (menisci).

Angular movements increase or decrease the angle between 2 bones. Movements include: Flexion Extension Hyperextension Abduction Adduction Circumduction

Diseases of the joints Besides trauma, inflammation from over use or repetitive motions are the most common diseases seen in the joints.

Bursitis Inflammation of a bursal sac usually as the result of chronic irritation