JOINTS OBJECTIVES Be able to classify the joints of the body both structurally and functionally Be able to classify the joints of the body both structurally and functionally Be able to identify example classification of joint Be able to identify example classification of joint Be able to describe the structure of a synovial joint Be able to describe the structure of a synovial joint JOINTS A joint is the location at which two or more bones make contact A joint is the location at which two or more bones make contact Function is to allow movement and provide mechanical support Function is to allow movement and provide mechanical support Joints are classified in two ways: Joints are classified in two ways: Structurally Structurally Functionally Functionally STRUCTURAL CLASSIFICATION OF JOINTS Is based on how the bones are connected to each other Is based on how the bones are connected to each other Fibrous joint: bones joined by fibrous connective tissue Fibrous joint: bones joined by fibrous connective tissue Example: skull and pelvis Example: skull and pelvis Cartilaginous joint: bones joined by cartilage Cartilaginous joint: bones joined by cartilage Example: spine and ribs Example: spine and ribs Synovial joint: bones not directly joined, but separated by cavities filled with synovial fluid, which lubricates and protects the bones Synovial joint: bones not directly joined, but separated by cavities filled with synovial fluid, which lubricates and protects the bones Example: shoulder, hip, knee, etc Example: shoulder, hip, knee, etc FUNCTIONAL CLASSIFICATION OF JOINTS Is based on the degree of mobility a joint will allow Synarthrosis: joints that permits little or no mobility; most are fibrous joints Example: skull & pelvis Amphiarthrosis: joints that permit slight mobility; most are cartilaginous joints Example: the vertebrae Diarthrosis: joints that permit a variety of movements; all of them are synovial joints Example: knees and elbows TYPES OF SYNOVIAL JOINTS Hinge Hinge Saddle Saddle Ellipsoid/Condyloid Ellipsoid/Condyloid Ball and Socket Ball and Socket Pivot Pivot Gliding Gliding JOINT STRUCTURE The bones that ends in a synovial joint are covered and protected by a special type of cartilage called articular cartilage Articular cartilage is smooth and slightly compressible Surrounding the joint is the joint capsule, which is made of strong connective tissue Lining the joint capsule is a delicate tissue called the synovial membrane JOINT STRUCTURE CONT. The synovial membrane constantly secretes synovial fluid into the synovial cavity Synovial fluid lubricates the joint, nourishes the cartilage with fats and proteins Its like uncooked egg white Ligaments attach the bone ends together to prevent them from moving too far or in unnatural directions SPECIAL CASE Some synovial joints are partially or completely divided into two compartments by discs of fibrocartilage called menisci (meniscus s.) between the articular surfaces Some synovial joints are partially or completely divided into two compartments by discs of fibrocartilage called menisci (meniscus s.) between the articular surfaces In the knee, they help to cushion the articulating surfaces and help distribute body weight on the surfaces In the knee, they help to cushion the articulating surfaces and help distribute body weight on the surfaces Fluid-filled sacs called bursae are also sometimes present Fluid-filled sacs called bursae are also sometimes present Bursae contain synovial fluid and are located between the skin and underlying bony prominences Bursae contain synovial fluid and are located between the skin and underlying bony prominences They aid in the movement of tendons that glide over bony parts or other tendons as well as provide cushion They aid in the movement of tendons that glide over bony parts or other tendons as well as provide cushion SYNOVIAL JOINT OF THE KNEE