Chapter 8 Articulations and Movement Articulation or Joint Place where two bones come together Freely movable to limited to no apparent movement Structure correlated with movement Named According to bones or parts united at joint According to only one of articulating bones By Latin equivalent of common name Syndesmoses Bones farther apart than suture and joined by ligaments Slightly movable Some movement may occur Classes of Joints Structural: Based on major connective tissue type that binds bones Fibrous – little or no movement Cartilaginous – little or no movement Synovial Functional: Based on degree of motion Synarthrosis: Nonmovable Amphiarthrosis: Slightly movable Diarthrosis: Freely movable Fibrous Joints Characteristics United by fibrous connective tissue Have no joint cavity Move little or none Types Sutures – skull, interlocking, sutural ligament (2 layers periosteum + dense fibrous tissue) Synostosis – sutures becomes fully ossified Syndesmoses Gomphoses Gomphoses Specialized joints Pegs that fit into sockets Periodontal ligaments – connective tissue bundles between teeth and socket, slightly realigned by braces Inflammations Gingivitis Periodontal disease Cartilaginous Joints Unite two bones by means of cartilage Types Synchondroses Joined by hyaline Little or no movement Symphyses Fibrocartilage uniting two bones Bursitis Articular disk – flat pad of fibrocartilage Meniscus – type of articular dick that only partially spans the synovial cavity such that there is an opening at the center. Synchondroses Temporary Ex. Epiphyseal plate of growing bones – synostosis Costochondral joints - synchondroses Types of Synovial Joints Plane or gliding Saddle Hinge Pivot Ball-and-socket Ellipsoid Synovial Joints Allow considerable movement Most joints that unite bone of appendicular skeleton Complex Articular cartilage and disks Joint cavity and capsule Synovial membrane and fluid Bursae Pockets of synovial fluid Movements at synovial joints Uniaxial/Monoaxial – one axis Biaxial- two axes at right angles to each other Multiaxial – several axes Saddle and Hinge Joints Saddle Joints Biaxial Saddle shape Example: Thumb Hinge Joints Monoaxial Convex cylinder in one bone correspond concavity to other bone Example: elbow, knee Plane and Pivot Joints Plane or Gliding joints Monoaxial Two flat bone surfaces about equal size, slight gliding motion Example: Articular processes between vertebrae Pivot joints Monoaxial Restricts movement to rotation around a single axis Cylindrical bony process that rotates within a ring of ligaments and bone Example: Articulation between dens of axis and atlas Ellipsoid and Ball-and-Socket Joints Ellipsoid Modified ball-and-socket Articular surfaces are ellipsoid in shape rather than spherical Biaxial Example: Atlantooccipital joint Ball-and-socket Multiaxial Examples: shoulder and hip joints Dorsiflexion and Plantar Flexion Types of Movement Gliding – occur in plane joints between two flat or nearly flat surfaces that glide over each other (ex. Carpal bones) Angular Flexion and Extension Hyperextension Plantar and Dorsiflexion Abduction and Adduction Circular Rotation Pronation and Supination Circumduction Abduction and Adduction Flexion and Extension Rotation and Pronation and Supination Circumduction Special Movements Unique to only one or two joints Types Elevation and Depression Protraction and Retraction Opposition and Reposition Inversion and Eversion Excursion Opposition and Reposition Elevation and Depression Protraction and Retraction Inversion and Eversion Range of Motion Amount of mobility demonstrated at a given joint Types Active – amount of movement accomplished by contracting the muscles that normally act across a joint Passive – amount of movement accomplished when structures that meet at the joint are moved by an outside force Influenced by Shape of articular surfaces forming joint Amount and shape of cartilage covering surfaces Strength and location of ligaments and tendons Location of muscles associated with joint Amount of fluid in and around joint Amount of use/disuse of joint Amount of pain in and around joint Shoulder Joint Temporomandibular Joint TMJ Combination plane and ellipsoid joint TMJ Disorders Cause most chronic orofacial pain Elbow Joint Hip Joint Knee Joint Modified hinge joint Menisi: Fibrocartilage articular disks Cruciate ligaments: ACL and PCL Collateral ligaments: Fibular and tibial Knee Injuries and Disorders Football injuries Bursitis Chondromalacia Softening of cartilage Hemarthrosis: Acute “Water on the knee” Slower accumulation Ankle Joint Highly modified hinge joint Ligaments of arch Hold bones in proper relationship Transfer weight Effects of Aging on Joints Tissue repair slows Production of synovial fluid declines Ligaments and tendons become less flexible Decrease in ROM Joint Disorders Arthritis Osteoarthritis: Wear and tear Rheumatoid: Caused by transient infection or autoimmune disease Joint infections Lyme disease: Tick vector Gout Metabolic disorders of unknown cause (idiopathic)
