A&P CH 9 PDF

Chap 9 Functional classifications of joint  Two classification schemes –Structural (anatomy) –Functional (range of motion) Joint structure determines function  Structural classifications –Fibrous –Cartilaginous –Bony –Synovial Functional classifications –Synarthrosis (immovable joint) –Amphia...

Chap 9 Functional classifications of joint  Two classification schemes –Structural (anatomy) –Functional (range of motion) Joint structure determines function  Structural classifications –Fibrous –Cartilaginous –Bony –Synovial Functional classifications –Synarthrosis (immovable joint) –Amphiarthrosis (slightly movable joint) –Diarthrosis (freely movable joint) Synarthrosis (immovable joint) –Very strong –Edges of bones may touch or interlock –May be fibrous or cartilaginous –Four types of synarthrotic joints ▪Suture ▪Gomphosis ▪Synchondrosis ▪Synostosis  Synovial joints (diarthroses) –Freely movable joints –At ends of long bones –Surrounded by joint capsule (articular capsule) ▪Contains synovial membrane –Synovial fluid from synovial membrane ▪Fills joint cavity –Articular cartilage covers articulating surfaces ▪Prevents direct contact between bones Synovial joints  Synovial joints are mobile but relatively weak Stabilized by accessory structures –Cartilages and fat pads –Ligaments –Tendons –Bursae  Tendons –Attach to muscles around joint Bursae –Small pockets of synovial fluid –Cushion areas where tendons or ligaments rub against other tissues Factors that stabilize synovial joints –Prevent injury by limiting range of motion ▪Collagen fibers of joint capsule and ligaments ▪Shapes of articulating surfaces and menisci ▪Other bones, muscles, or fat pads ▪Tendons attached to articulating bones Sprain- ligament with torn fibers Movements, Triaxial etc  Movements are described in terms that reflect the –Plane or direction of movement –Relationship between structures Planes of movement –Monaxial—1 plane (e.g., elbow) –Biaxial—2 planes (e.g., wrist) –Triaxial—3 planes (e.g., shoulder)  Saddle joint –Articular faces fit together like a rider in a saddle –Biaxial Pivot joint –Rotation only –Monaxial Ball-and-socket joint –Round head in a cup-shaped depression –Triaxial