JOINTS Fibrous Joints Composed of articulating bones joined by dense collagen fibers Little elasticity Allow no empty spaces between surfaces Fibrous connective tissue forms union of irregular bones along full common borders Allows no movement and called synarthrosis Three types of fibrous joints suture syndesmosis and gomphosis o Suture example bones of cranium in adult no movement o Syndesmosis example interosseous ligament between tibia and fibula slight movement o Gomphosis example root of tooth attaches to jaw no movement Cartilaginous Joints Cartilage is tissue also made of collagen Similar to bone and fibrous tissue but lacks calcium No blood or nutrient supply to cartilage Flexible and strong and good shock absorber Three types of cartilage hyaline elastic and fibrocartilage Two types of cartilaginous joints synchondrosis and symphysis There are no empty spaces between surfaces of cartilaginous joints Synchondroses A cartilaginous joint during youthful years that absorbs calcium in adulthood and loses flexibility Epiphysial plate is an example Between first rib and sternum and between manubrium and body of sternum Once complete is immovable or synarthrotic Symphyses Primarily made of cartilage but has greater elasticity and flexibility than synchondrosis Example pubic symphysis articulation of vertebral body with one above below A slight degree of movement is allowed called amphiarthrotic or amphiarthrosis Synovial Joints Most common type in body Freely movable Examples shoulder hip knee etc Called diarthrosis or diarthrotic joint movement Six types responsible for specific functional movement Movements occur on three planes the number of planes a joint moves on is the degree of movement or freedom Elements allow movement and simultaneous joint integrity and stability o Articular cartilage synovial cavity joint capsule synovial membrane synovial fluid and ligaments Articular cartilage is hyaline covers ends of bones for smooth slick surface shock absorber Joint cavity is empty space between two bones to allow movement Joint capsule is enclosed sac that surrounds all other structures of the joint Made of fibrous connective tissue and attaches to periosteum Synovial membrane is thin inner lining of joint capsule Covers everything but areas of articular cartilage Made of loose connective tissue with blood supply and creates synovial fluid for lubrication and sources of food and healing Ligaments help hold joint together with joint capsule Some ligaments are inside joint capsule others outside No blood supply so poor healing potential Other elements not found in all synovial joints include Meniscus Bursa Tendon sheaths Labrum Muscle A 1st class lever is a type of joint in the human body one example is the joint found between the skull and the atlas vertebrae of the spine The spine is the fulcrum across which muscles lift the head Such connections between joints called synovial joints are fulcrums the bones they connect are levers and the muscles attached to them apply force or resistance A second class lever is a type of lever in the human body one example is the Achilles tendon pushing or pulling across the heel of the foot Such connections between joints called synovial joints are fulcrums the bones they connect are levers and the muscles attached to them apply force or resistance A third class lever might be the elbow joint when lifting a book the elbow joint is the fulcrum across which the biceps muscle performs the work Such connections between joints called synovial joints are fulcrums the bones they connect are levers and the muscles attached to them apply force or resistance Chapter 9 Joints Point where 2 bones meet articulation Some are moveable some are not Arthrology study of joints structure function and disfuction Kinesiology muscular skeletal movement Biomechanics varies movement mechanical process of body physics of blood circulation Joints are named from the bones they are associated with 1 Bony joints 2 Fibrous joints a Sutures Immovable joint 2 bones come together to form 1 bone Adjacent bones are joined together by collagen fibers a Serrate inner lock with each other b Lap over lapping c Plane b Gomphoses teeth to socket c Syndesmosis 2 bones bound by long collegous fibers 3 Cartilaginous joints 2 bones bound by cartilage a Synchondroses bone bound by hyaline cartlige b Symphyses 2 bones joined by fibrocartilage 4 Synovial joints Movement of Synovial joints Flexion decreases angle of joint Extension straightens a joint Hyperextension extension beyond zero position Abduction movement away from midline Adduction movement toward midline Elevation raises a body part vertically in frontal plane Depression lowers a body part vertically in frontal plane Protraction anterior movement in transverse plane Retraction posterior movement in transverse plane Circumduction one end of appendage is still while the other end moves in a circular manner Rotation bone spins on longitudinal axis Supnation palm faces anteriorally supine abdomen faces up Pronation palm faces posteriorally prone abdomen faces down Dorsiflexion elevate toes Plomtar flexion point toes downward Inversion sole faces medially Eversion soles faces laterally