Anatomy Objectives OBJECTIVES: Begin Chapter 8 Joints Functional & structural classifications of joints Quiz Joint Classification Fri 12/15 Quiz Synovial Joint Knee Wed 1/3 Test Chapter 8 Friday 1/5 HOMEWORK: Study for quiz classifications Joints (Articulations) Weakest parts of the skeleton Articulation site where two or more bones meet Functions of joints Give the skeleton mobility Hold the skeleton together Classified in two ways functionally and structurally Classification of Joints: Functional Functional classification is based on the amount of movement allowed by the joint The three functional classes of joints are: Synarthroses immovable Amphiarthroses slightly movable Diarthroses freely movable Classification of Joints: Structural Structural classification focuses on the material binding bones together and whether or not a joint cavity is present The three structural classifications are: Fibrous Cartilaginous Synovial Structural Joints 1.Fibrous joints, united by fibrous connective tissue; have no joint cavities -may be rigid to slightly movable; 3 types A)sutures found only in skull; interlocking; immovable; synarthrotic joints B)syndesmoses joint held by collagenous fibers or interosseous ligaments; permits only slight movement; amphiarthrotic joints Sutures of the skull Syndesmoses of the ulna-radius C)Gomphoses occur between teeth and the supporting bones of the jaws; where root of tooth is attached to periodontal ligament of tooth socket; synarthrotic joint 2.Cartilaginous joints bone ends are joined by hyaline cartilage or fibrocartilage; limited motion, amphiarthrotic; two types A)symphyses bones separated by pad of fibrocartilage; allows slight movement Symphysis pubisintervertebral discs B)Synchondroses cartilaginous joints that have hyaline cartilage between bones -ex. Immature long bone where an epiphysis is connected to a diaphysis by a band of hyaline cartilage (the epiphyseal disk); movement no longer occurs in adult; synarthrotic 3.Synovial joints - Joint cavities ; allow free movement diarthrotic; those in which articulating bone ends are separated by a joint cavity containing synovial fluid; all have 4 distinguishing features 1)articular cartilage covers ends of bones 2)fibrous articular capsule joint surfaces are enclosed by a sleeve or capsule of fibrous connective tissue and the capsule is lined with a smooth synovial membrane which secretes fluid 3)joint cavity articular capsule encloses a cavity which contains lubricating synovial fluid (Greek = egg white) 4)Reinforcing ligaments fibrous capsule is usually reinforced with ligaments located within the joint cavity or on outside of capsule -bursae - fluid-filled synovial membrane sacs - often found cushioning tendons where they cross bone -menisci tough, fibrous pads located within capsule of some joints; cushion & guide articulating bones Synovial Joints: Friction-Reducing Structures Structure of knee joint Synovial joints provide a wide range of motion which may be determined by three factors 1.The structure of the bones involved in the articulation (processes may limit motion) 2.The strength and tautness of ligaments, tendons, and joint capsule 3.The size, arrangement, and action of muscles spanning joints Double-jointed?? no extra joints; many are able to stretch ligaments surrounding joints Six types of synovial joints 1.Plane joints - articulating surfaces are nearly flat or slightly curved -allows only sliding or back-and-forth motion -includes joints within the wrist and ankle, and those between articular processes of adjacent vertebrae 2.Pivot joints -cylindrical surface of one bone rotates within a ring formed of bone and fibrous tissue - motion limited to rotation around central axis - includes joint between proximal ends of radius and ulna, and in neck as atlasrotates around odontoid process of axis 3.Hinge joint - convex surface on one bone fits into concave surface of another -resembles hinge of door; permits movement in one plane only -includes elbow and joints of phalanges 4.Condyloid joint - ovoid condyle of one bone fits into the elliptical cavity of another bone -permits variety of movement in different planes; no rotational - includes joints between metacarpals and phalanges 5.Saddle joint - formed between bones whose articulating surfaces have both concave and convex regions -surface of one bone fits the complementary surface of the other -permits variety of movement -includes joint between carpal and metacarpal of thumb 6.Ball and socket joint - consists of bone with globular head that articulates with the cup- shaped cavity of another -allows for wider range of motion than any other kind of joint -movements in all planes; includes rotation around central axis -includes joints of hip and shoulder Synovial Joints: Knee Largest and most complex joint of the body Allows flexion, extension, and some rotation Three joints in one surrounded by a single joint cavity Femoropatellar joint Lateral and medial tibiofemoral joints Synovial Joints: Knee Other Supporting Structures Figure 8.8b Synovial Joints: Knee Ligaments and Tendons Anterior View Tendon of the quadriceps femoris muscle Lateral and medial patellar retinacula Fibular and tibial collateral ligaments Patellar ligament Figure 8.8c Synovial Joints: Knee Posterior Superficial View Adductor magnus tendon Articular capsule Oblique popliteal ligament Arcuate popliteal ligament Semimembranosus tendon Figure 8.8e Synovial Joints: Movement The two muscle attachments across a joint are: Origin attachment to the immovable bone Insertion attachment to the movable bone Described as movement along transverse, frontal, or sagittal planes Gliding Movements One flat bone surface glides or slips over another similar surface Examples intercarpal and intertarsal joints, and between the flat articular processes of the vertebrae Gliding Movement Figure 8.5a Angular movements increase or decrease the joint angle; all are in reference to anatomical position Flexion bending parts at a joint so that the angle between them is decreased and the parts come closer together; bending leg at the knee Extension straightening parts at a joint so that the angle between them is increased and the parts move further apart Hyperextension extending part beyond the anatomical position (beyond 180 o ); bending head back Angular Movement Plantar flexion extending the foot at the ankle; bending the foot downward Dorsiflexion flexing the foot at the ankle; bending the foot upward Abduction moving a part away from the midline; lifting the arm horizontally to form a right angle with the side of the body Adduction moving a part toward the midline; returning the arm from the horizontal position to the side of the body Rotation moving a part around an axis; twisting the head from side to side Angular Movement Figure 8.5e, f Angular Movement Figure 8.5c, d Circumduction moving a part so that its end follows a circular path; moving the finger in a circular motion without moving the hand Supination turning the hand so the palm is upward Pronation turning the hand so the palm is downward Eversion turning the foot so the sole is outward Inversion turning the foot so the sole is inward Protraction moving a part forward; thrusting the chin forward Retraction moving a part backward; pulling the chin backward Rotation Elevation raising a part; shrugging the shoulders Depression lowering a part; dropping the shoulders Joint Disorders are varied and numerous Dislocation (luxation) when a bone is forced out of its normal position in joint cavity; reductions should only be done by a physician to avoid doing more harm than good Subluxation partial dislocation of a joint Torn anterior cruciate ligament (ACL) occurs when athlete pivots quickly on one leg in order to change direction;person hears a pop from the knee; knee becomes severely swollen due to bleeding within the joint; slow healing due to poor blood supply Ankylosis loss of mobility of a joint; fixed joint Temporomandibular joint (TMJ) syndrome afflicts 75 million Americans; usually due to misalignment of joint; symptoms vary and may include pain in head, neck, shoulders, & back, ringing in ears, dizziness Bursitis water on the knee; inflammation of bursae or synovial membrane Sprain ligaments or tendons reinforcing a joint are damaged by excessive stretching, or are torn away from bone; heal very slowly Strain result of overexertion Synovitis inflammation of joint capsule Arthroscopy examination of interior of joint using tubular arthroscope Arthritis describes over 100 different inflammatory or degenerative diseases that damage joints; most widespread, crippling disease in US; symptoms include pain, stiffness, swelling of joint, damage to joint structure; may be caused by trauma to joint, genetic & metabolic disorders -osteoarthritis most common form; chronic degenerative condition; wear & tear arthritis; -articular cartilage softens, frays, & breaksdown; bone thickens & may form bone spurs which protrude into joint cavity -joints make crunching noise when moved - slowly progressing; irreversible; rarely crippling - rheumatoid arthritis autoimmune disease disorder in which the bodys immune system attempts to destroy its own tissues -begins with inflammation of synovial membranes; membranes thicken and fluid accumulates -cartilage is destroyed, scar tissue forms & connects bone ends (fuses them together) -all cases involve restricted joint movement and extreme pain -Gouty arthritis (gout) disease in which uric acid accumulates in blood and is deposited as crystals in soft tissues of joints -salt crystals irritate articular cartilage and synovial membrane, causing swelling, tissue deterioration, and pain -common in great toe; most common in males -bone ends may fuse and joint becomes immobilized Joint prostheses artificial articulations Replace synovial joints; reduce unbearable pain and increase joint mobility in chronically disabled arthritis patients Quiz - Articulations 1.List the three types of functional joints & describe how they differ. 2.List the three types of structural joints & describe how they differ. 3.List & describe the four features all synovial joints have. Knee Quiz -Midsagittal Knee Anterior View