Joints Articulations Classification of Joints 2 ways Functional Classification based on amount of movement allowed at the joint 3 Types Synarthrotic joints Synarthroses immovable joints Amphiarthrotic joints Amphiarthroses slightly movable joints Diarthrotic joints Diarthroses freely movable joints Structural Classification based on the material binding the bones at the site and the absence or the presence of a joint cavity 3 Types Fibrous Joints Cartilaginous joints Synovial joints 3 Structural Classes of Joints Fibrous Joints bones joined together by dense CT type of fibrous CT joint cavity absent 3 types or bones are connected by interosseous membranes Amphiarthrotic joints Sutures located only in the skull Functional class of sutures in baby skull Amphiarthrotic joints Functional class of sutures in adult skull Synarthrotic joints Gomphoses located only between teeth and bony alveolar sockets Functional class of gomphoses Synarthrotic joints Syndesmoses bones are connected by ligaments Synarthrotic joints Cartilaginous Joints cartilage connects the bones joint cavity absent 2 types Synchondroses Hyaline cartilage connects bones Synarthrotic joints Symphyses Fibrocartlage connects bones Amphiarthrotic joints Synovial Joints ligaments bind the bones Joint cavity present ALL Synovial joints are Diarthrotic joints Plane joints Pivot joints Saddle joints Hinge joints Condyloid joints Ball and socket Cartilaginous Joints 2 types Synchondroses cartilaginous joints with bones connected by hyaline cartilage Functional class of synchondroses Synarthrotic joints Example Epiphyseal plates composed of hyaline cartilage connecting the diaphysis and the epiphyses of a long bone Symphyses cartilaginous joints with bones connected by fibrocartilage Functional class of symphyses Amphiarthrotic joints Examples Intervertebral discs Pubic symphysis General Characteristics of Synovial Joints Articular cartilage caps the ends of the bones Joint Cavity space that contains synovial fluid which acts like a lubricant to reduce friction Articular Capsule double layered consists of an outer fibrous capsule and an inner synovial membrane Ligaments that reinforce synovial joints 3 types of ligaments based on their location in relation to the articular capsule Capsular or intrinsic ligaments located inside the fibrous capsule example medial collateral ligaments Extracapsular ligaments located external to the articular capsule example tibial collateral ligaments Intracapsular ligaments located deep to the articular capsule example anterior cruciate ligament ACL a blow to the front of the extended knee tears the ACL a common sport injury MENISCI discs of fibrocartilage that extend from the articular capsule into the synovial cavity to improve the fit of a synovial joint which minimizes wear and tear BURSAE flattened fibrous sacs that contain synovial fluid to reduce friction where bones tendons ligaments and muscles rub together TENDON SHEATHS elongated bursae that wrap completely around tendons subjected to a lot of friction tendon sheaths reduce friction All Synovial Joints are Diarthrotic Joints Some movements allowed at Synovial joints Gliding slipping movements Flexion movement that decreases the angle of a joint Extension movement that increases the angle of a joint Abduction movement of a limb AWAY from the midline of the body Adduction movement of a limb TOWARD the midline of the body Circumduction movement of the limb that describes a cone in space Rotation movement of a bone around an axis 6 Types of Synovial Joints Plane joint articulating surfaces are flat Hinge joint one articular surface is cylindrical and the other surface is a trough intercarpals intertarsals Gliding movements allowed Flexion extension allowed Examples elbow joint knee joint Pivot joint one articular surface is round and the other surface is a sleeve or ring Condyloid joint one articular surface is oval protrusion and the other surface is an oval depression Rotation allowed Examples Radioulnar joint atlanto axial joint allows us to move the head side to side to motion NO Flexion Extension Abduction Adduction Circumduction allowed Examples metacarpophalangeal joints knuckles atlanto occipital joint allows us to move head up and down to motion YES Saddle joint one articular bone has both convex and concave surfaces and the other articular bone has both concave and convex surfaces in reverse flexion extension abduction adduction Circumduction allowed carpometacarpal joint of the thumb the only example in the human body Ball and socket joint one articular surface is a spherical head and the other surface is a cuplike socket ALL movements allowed shoulder joint hip joint Arthritis a disease characterized by inflammation of synovial membranes that causes stiff and painful joints
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