Slide 1

Bone Articulations and Movement Articulations: Definition Classification of Joints: Functional classification Structural classification Synovial Joints Terminology of Movements

Slide 2

Articulations Articulations (or joints) are places where two or more bones meet - required if motion is to occur - structure and function are interrelated - each articulation balances the need for stability versus the need for mobility

Slide 3

Classification of Articulations Joints can be classified based on : - the amount of motion occurring at the joint - the structure and composition of the joint

Slide 4

Classification of Articulations by Function The classification of joints by function (amount of movement) is as follows: - Synarthroses: little or no movement in the joint (extremely strong joint) example: sutures between bones of the skull - Amphiarthrosis: slightly movable joint (strong, yet slightly mobile joint) example: pubic symphysis, intervertebral discs - Diarthrosis: freely movable joint (weakest type) examples: shoulder, elbow, hip, knee joints

Slide 5

Classification of Articulations by Structure There are three types of joints classified by structure: fibrous, cartilagenous, and synovial joints. Fibrous joints - joints in which bones are held together by fibrous CT - sutures: between bones of the skull - synostosis: two bones grow across joint to form a single bone (fusion of two frontal bones) - syndesmosis: gap between bones wider than in suture (interosseus membrane of radio-ulnar joint) - gomphoses: joints in which one end fits into socket of other bone (teeth held in alveoli by periodontal ligaments; fig 24.6)

Slide 6

Slide 7

Slide 8

Slide 9

Slide 10

Cartilagenous Joints Joints in which bones are united by hyaline of fibrocartilage. - synchondroses: cartilagenous joint in which the bones are joined by hyaline cartilage (example: costal cartilage to sternum) - symphysis: cartilagenous joint in which the bones are joined by fibrous cartilage (example: symphysis pubis, intervertebral discs)

Slide 11

Slide 12

Slide 13

Slide 14

Slide 15

Synovial Joints Synovial joints are those that have a joint cavity containing synovial fluid. Since there is a lot of movement in diarthrotic joints, you need: - extra space between bones - a lubricating fluid to reduce friction. Synovial joints are usually found at the ends of long bones.

Slide 16

Structure of Synovial Joints Features of synovial joints: - enclosed in a joint capsule (outer: fibrous capsule, inner: synovial membrane) - the synovial membrane secretes synovial fluid - the ends of bone are covered by articular cartilage (hyaline) - movement can be mono- axial, biaxial, or multiaxial

Slide 17

Slide 18

Bursae In some joints, the synovial membrane may extend outside the joint itself as a pocket, or bursa. A bursa provides protection between bone and tendons, or between skin and bone.

Slide 19

Slide 20

Types of Synovial Joints Synovial joints can be classified based on the shapes of the adjoining articular surfaces: gliding: manubrio-clavicular joint (monoaxial: one plane) hinge: monoaxial (elbow), convex cylinder of one bone into a concavity of another bone

Slide 21

Types of Synovial Joints Pivot: monoaxial, rotation around a single axis Saddle joint: two saddle- shaped articular surfaces at right angles to each other; biaxial

Slide 22

Types of Synovial Joints Ball and socket: ball (head) of one bone into socket of adjacent bone; multiaxial Condyloid (ellipsoid): like a ball and socket, except ball is more oval; biaxial.

Slide 23

Slide 24

Slide 25

Slide 26

Slide 27

Slide 28

Slide 29

flexion: movement in the anterior/posterior plane that reduces the angle between articulating bones

Slide 30

Slide 31

extension: movement in the same plane that increases the angle between bones

Slide 32

Slide 33

- plantarflexion: movement of the foot toward the plantar surface - (standing on toes) - dorsiflexion: movement of the foot toward the the shin (note that this is really extension of the foot!)

Slide 34

abduction: moving away from the longitudinal axis of the body in the frontal plane (moving back is adduction) circumduction: combination of flexion, extension, abduction, and adduction that moves the limb in a cone

Slide 35

rotation: turning around the longitudinal axis

Slide 36

Upper limb: - pronation: rotation of the forearm so that the palm faces posteriorly - supination: rotation of the forearm so that the palm faces anteriorly

Slide 37

Lower limb: - inversion: turning the ankle so that the plantar surface (sole) faces medially - eversion: turning the ankle so that the plantar surface faces laterally

Slide 38

protraction: moving a structure anterioly retraction: moving a structure posteriorly

Slide 39

elevation: moving a structure superiorly depression: moving a structure inferiorly

Slide 40

Slide 41

Next Lecture.... The Muscular System: Gross Anatomy of Skeletal Muscle