JOINTS TORTORA

• JOINT - point of contact between two bones, between bone and cartilage, or between bone and teeth.
• arthrology - scientific study of joints is termed
• kinesiology - study of motion of the human body
• FIBROUS JOINTS - united by dense irregular connective tissue (mainly collagen fibers); varies from immovable to slightly movable and depends in most cases on the length of the collagen fibers that join the articulating bones.
• CARTILAGINOUS JOINTS - characterized by the presence of a solid piece of hyaline cartilage or fibrous cartilage; Range from immovable to slightly movable
• subtype of fibrous joints - SUTURES and SYNDESMOSES
• subtype of cartilaginous joints - SYNCHONDROSES and SYMPYSES
• SYNOVIAL JOINTS - they are most of the joints in your body; characterized by a two layered articular capsule that unites the articulating bones and surrounds a lubricated space called an articular cavity; range from slightly movable to freely movable
• suture - fibrous joint composed of a thin layer of dense irregular connective tissue; occur only between bones of the skull
• a suture is called a SYNOSTOSIS, or bony joint—a joint in which there is a complete fusion of two separate bones into one
• If the suture persists beyond age 6, it is called a frontal (metopic) suture. It is immovable
• SYNDESMOSIS - a fibrous joint in which there is generally a greater distance between the articulating surfaces and more dense irregular connective tissue than in a suture
• INTEROSSEOUS LIGAMENT - ex. anterior tibiofibular ligament which connects the distal tibia and fibula at the distal tibiofibular
• INTEROSSEOUS MEMBRANE - a substantial sheet of dense irregular connective tissue that binds neighboring long bones and permits slight movement; occur between the radius and ulna in the forearm and between the tibia and fibula in the leg
• GOMPHOSIS - or DENTOALVEOLAR joint, in which a cone-shaped peg fits into a cavity with a small amount of dense irregular connective tissue; ex. articulations between the roots of the teeth and their dental alveoli
• SYNCHONDROSIS - a cartilaginous joint in which the connecting material is a solid piece of cartilage that allows little or no movement; articulating bones are lightly connected by hyaline cartilage or fibrous cartilage; ex. JOINT BETWEEN FIRST RIB AND MANUBRIUM
• EPIPHYSEAL CARTILAGE - Another type of synchondrosis ; hyaline cartilage growth centers during endochondral bone formation, not joints associated with movements
• SYMPHYSIS - cartilaginous joint in which the ends of the articulating bones are covered with hyaline cartilage, but a broad, flat disc of fibrous cartilage connects the bones; occur in the midline of the body
• a unique characteristic of a synovial joint is the presence of a space between the articulating bones called an ARTICULAR CAVITY.
• The surfaces of the bones within a synovial joint are covered by a layer of hyaline cartilage called ARTICULAR CARTILAGE
• ARTICULAR CAPSULE or joint capsule surrounds a synovial joint, encloses the articular cavity, and unites the articulating bones. They are composed of two layers, an outer fibrous layer and an inner synovial membrane
• ARTICULAR CAPSULEPART

  FIBROUS LAYER - usually consists of dense irregular connective tissue that attaches to the periosteum of the articulating bones; literally a thickened continuation of the periosteum between the bones
• ARTICULAR CAPSULE PART

  inner layer of the articular capsule, the SYNOVIAL MEMBRANE is composed of areolar connective tissue with collagen and elastic fibers.
• At many synovial joints the synovial membrane includes accumulations of adipose tissue, called ARTICULAR FAT PADS
• LIGAMENTS - fiber bundles; The fibers of some fibrous membranes are arranged as parallel bundles of fibrous connective tissue that are highly adapted for resisting strains.
• The synovial membrane secretes SYNOVIAL FLUID, a viscous, clear or pale yellow fluid named for its similarity in appearance and consistency to uncooked egg white. consists of hyaluronic acid secreted by synovial cells (SYNOVIOCYTES) in the synovial membrane and interstitial fluid filtered from blood plasma
• the synovial membrane may extend as a pocket, or sac, called a BURSA; located between structures that rub together, such as where a tendon crosses a bone; they reduce friction, which could damage the structures involved.
• EXTRACAPSULAR LIGAMENTS - lie outside the articular capsule. Examples are the fibular collateral ligaments of the knee joint or thickening of the external region of the articular capsule, such as the tibial collateral ligament of the knee joint
• INTRACAPSULAR LIGAMENTS - occur within the articular capsule but are excluded from the articular cavity by folds of the synovial membrane. Examples are the anterior and posterior cruciate ligaments of the knee joint
• crescent shaped pads of fibrous cartilage lie between the articular surfaces of the bones and are attached to the fibrous capsule. These pads are called ARTICULAR DISCS or MENISCI
• LABRUM - prominent in the ball and socket joints of the shoulder and hip; ring-like fibrous cartilage lip that extends from the circumference of the joint socket
• PLANE JOINTS - gliding joints; consist of two opposed flat surfaces that glide over each other; arthrodial JOINT
• SADDLE JOINTS - SELLAR JOINT; consist of two saddle-shaped articulating surfaces oriented at right angles to each other. Movement in these joints can occur in two planes; ex. METACARPOPHALANGEAL JOINT
• HINGE JOINTS - permit movement in one plane only. They consist of a convex cylinder of one bone applied to a corresponding concavity of the other bone; ex. elbow and knee joints
• ELLIPSOID JOINT - CONDYLAR JOINT; convex oval-shaped projection of one bone fits into the oval-shaped depression of another bone. ex. RADIOCALPAR JOINT
• BALL-AND-SOCKET JOINT - SPHEROIDAL JOINT; consists of the ball-like surface of one bone fitting into a cuplike depression of another bone; ex. HIP JOINT
• SYNARTHROSIS - nonmovable joint
• amphiarthrosis - slightly movable joint
• diarthrosis - freely movable joint