Popular in Anatomy and Physiology I
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This 9 page Bundle was uploaded by kgrunwaldt on Monday January 25, 2016. The Bundle belongs to BIOL 214 at Truman State University taught by Dr. Guffey in Spring 2016. Since its upload, it has received 18 views. For similar materials see Anatomy and Physiology I in Science at Truman State University.
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Date Created: 01/25/16
Joints Classification of Joints Structural classification focuses on the material binding the bones together and whether or not a joint cavity is present 0 Fibrous 0 Cartilaginous 0 Synovial Functional classification based on the amount of movement allowed at the joint 0 Synarthroses immovable o Amphiarthroses slightly movable o Diarthroses freely movable In general fibrous joints are immovable synovial joints are freely movable and cartilaginous joints can be either Fibrous Joints Bones are joined by fibrous tissue namely dense fibrous connective tissue and no joint cavity is present Sutures O Literally seams 0 Occur only between bones of the skull 0 Closed sutures are called synostoses literally bony junctions 0 Joint held together with very short interconnecting fibers and bone edges interlock Syndesmoses 0 Bones are connected exclusively by ligaments o Fibrous tissue can vary in length but is longer than in sutures Gomphoses o A peginsocket fibrous joint 0 Only example of articulation is a tooth with its bony alveolar socket o Fibrous connection in this case is the short periodontal ligament Cartilaqinous Joints The articulating bones are united by cartilage no joint cavity and are not highly movable O Synchondroses I A bar or plate of hyaline cartilage unites the bones I Virtually all synchondroses are synarthrotic I Most common examples are epiphyseal plates in the long bones of children I Another example is the immovable joint between costa cartilage of the first rib and the manubrium of the sternum 0 Symphyses I Articular surfaces of the bones are covered with articular hyaline cartilage which in turn is fused to an intervening pad or plate of fibrocartilage I Acts as a shock absorber and permits a limited amount of movement at the joint I Amphiarthrotic joints designed for strength and flexibility I Examples include intervertebral joints and the pubic symphysis of the pelvis Svnovial Joints Joints in which the articulating bones are separated by a fluidcontaining joint cava This arrangement permits freedom of movement and all synovial joints are diarthroses Nearly all joints of the limbs fall into this class General Structure 0 Articular cartilage Hyaline cartilage covers the opposing bone surfaces as articular cartilage Thin 1 mm or less but spongy cushions absorb compression placed on the joint 0 Joint synovial cavity Joint cavity is really just a potential space that contains a small amount of synovial fluid 0 Articular capsule External layer is a tough fibrous capsule composed of dense irregular connective tissue that is continuous with the periostea of the articulating bones lt strengthens the bones so that they are not pulled apart lnner layer is a synovial membrane composed of loose connective tissue 0 Synovial fluid Occupies all free spaces within the joint capsule Fluid is derived largely by filtration from blood flowing through the capillaries in the synovial membrane This fluid reduces friction between the cartilages 0 Reinforcing ligaments Synovial joints are reinforced by capsularintrinsic ligaments thickened parts of the fibrous capsule In other cases they remain distinct and are found outside the capsule extracapsular or deep to it intracapsular 0 Nerves and blood vessels Synovial joints are richly supplied with sensory nerve fibers that innervate the capsule to detect pain Blood vessels supply the synovial membrane to produce the blood filtrate that is the basis of synovial fluid Fatty pads cushions between the fibrous capsule and the synovial membrane or bone Articular discs menisci wedges of fibrocartilage that separate the articular sunaces Bursae and Tendon Sheaths Bursae flattened fibrous sacs lined with synovial membrane and containing a thin film of synovial fluid 0 Occur where ligaments muscles skin tendons or bones rub together Tendon sheath an elongated bursa that wraps completely around a tendon subjected to friction like a bun around a hot dog 0 Common where several tendons are crowded together within narrow canals Factors Influencinq the Stabilitv of Svnovial Joints Stability of synovial joints depends chiefly on three factors the shapes of the articular surfaces the number and positioning of ligaments and muscle tone Articular surfaces 0 Many joints have shallow sockets or noncomplementary articulating surfaces that actually hinder joint stability 0 When articular surfaces are large and fit snugly together or when the socket is deep stability is vastly improved 0 The ball and deep socket of the hip joint provide the best example of a joint made extremely stable by the shape of its articular surfaces Ligaments 0 Capsules and ligaments of synovial joints unite the bones and prevent excessive or undesirable motion 0 When other stabilizing factors are inadequate tension is put on the ligaments and they stretch 0 Stretched ligaments stay stretched o A ligament can only stretch 6 of its length before it snaps Muscle Tone 0 Muscle tendons that cross the joint are the most important stabilizing factors 0 Muscle tone is defined as low levels of contractile activity in relaxed muscles that keep the muscles healthy and ready to react to stimulation 0 Extremely important in reinforcing the shoulder knee joints and arches of the foot Movements Allowed bv Svnovial Joints Every skeletal muscle of the body is attached to bone or other connective tissue structures at no fewer than two points the origin and the insertion Body movement occurs when muscles contract across joints and their insertion moves toward their origin Nonaxial movement slipping movements only since there is no axis around which movement can occur axes Uniaxial movement movement in one plane Biaxial movement movement in two planes Multiaxial movement movement in or around all three planes of space and Three general types of movements gliding angular and rotation Gliding Movements I The simplest joint movements I Occurs when one flat bone surface glides or slips over another without appreciable angulation or rotation I Occur at the intercarpal and intertarsal joints Angular Movements I Increase or decrease the angle between two bones I May occur in any plane of the body and include flexion extension hyperextension abduction adduction and circumduction I Flexion bending movement usually along the sagittal plane that decreases the angle of the joint and brings bones closer together I Extension the reverse of flexion and occurs at the same joints I Hyperextension excessive extension such as extending the head or hip joint beyond anatomical position I Abduction movement of a limb away from the midline or median plane of the body along the frontal plane I Adduction the opposite of abduction the movement of a limb toward the body midline I Circumduction moving a limb so it describes a cone in space 0 Rotation I The turning of a bone around its own long axis I The only movement allowed between the first two cervical vertebrae and it is common at the hip and shoulder joints 0 Special Movements I Supination rotating the forearm laterally to that the palm faces supenony I Pronation rotating the forearm medially and the palm faces anteriorly I Dorsiflexion lifting the foot so that its superior surface approaches the shin I Plantar flexion depression of the foot I Inversion sole of the foot turns medially I Eversion sole of the foot turns laterally I Protraction anterior movements in a transverse plane I Retraction posterior movements in a transverse plane I Elevation lifting a body part superiorly I Depression moving the elevated part inferiorly I Opposition the action taken when you touch your thumb to the tips of other fingers on the same hand Tvnes of Svnovial Joints Plane Joints 0 Articular surfaces are essentially flat and allow only short nonaXial gliding movements I Example intercarpal and intertarsal joints Hinge Joints o The cylindrical end of one bone conforms to a troughshaped surface on another I Example bending and straightening the elbow and interphalangeal joints Pivot Joints 0 The rounded end of one bone conforms to a sleeve or ring composed of bone or ligaments of another I Example the joint between the atlas and dens of the axis Condyloid Joints 0 The oval articular surface of one bone fits into a complementary depression in another I Example radiocarpal and metacarpophalangeal joints Saddle Joints 0 Resemble condyloid joints but allow greater freedom of movement I Example carpometacarpal joints of the thumbs BallandSocket Joints 0 Spherical or hemispherical head of one bone articulates with the cuplike socket of another I Example shoulder and hip joints Selected Svnovial Joints Knee Joint o Largest and most complex joint in the body 0 Consists of three joints in one an intermediate one between the patella and the lower end of the femur femoropatellar joint and lateral and medial joints known as tibiofemoral joints between the femoral condyles and the menisci Shoulder Joint 0 Stability is sacrificed to provide the most freely moving joint of the body o Ballandsocket joint Elbow Joint 0 Provides a stable and smoothly operating hinge that allows flexion and extension only Hip Joint o Ballandsocket joint 0 Good range of motion Temporomandibular Joint o Lies anterior to the ear 0 Most easily dislocated joint in the body Common Joint Iniuries Cartilage tears 0 Occur when a meniscus is subjected to compression and shear stress at the same time o Arthroscopic surgery can help to remove cartilage pieces from the joint Sprains 0 Occur when the ligaments reinforcing a joint are stretched or tom 0 Partially torn ligaments repair themselves 0 Painful and immobilizing Dislocations quations 0 Occur when bones are forced out of alignment 0 Accompanied by sprains inflammation and difficulty in moving the joint Inflammatory and Degenerative Conditions Bursitis inflammation of a bursa and is usually caused by a blow or friction Tendonitis inflammation of tendon sheaths caused by overuse Arthritis describes over 100 different types of inflammatory or degenerative diseases that damage the joints and consists of pain stiffness and swelling of the joint Osteoarthritis degenerative joint disease most common chronic arthritis Rheumatoid arthritis a chronic inflammatory disorder with an insidious onset Lyme disease an inflammatory disease caused by spirochete bacteria transmitted by the bites of ticks that live on mice and deer
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