Presentation on theme: "Articular System (Joints) ANHB 2212 – 2007 Avinash Bharadwaj."— Presentation transcript:
Articular System (Joints) ANHB 2212 – 2007 Avinash Bharadwaj
Joints “Articulation” Articulatio / Arthron Arthrology Where two or more bones or parts of bones unite… How they are joined together… the tissues that unite bones
Joint Classification Structural The tissues that unite bones Functional Mobility or otherwise Synovial joints – axes of movements No perfect system (Explained as we go!) Arbitrary and confusing terms Overlapping terminology Latin terminology and anglicised versions The choice is yours!
Tissues Uniting Bones Fibrous tissue Unossified tissue between membrane bones (Explained fully next week!) Ligaments (Dense connective tissue!) Cartilage Hyaline cartilage White fibrocartilage Fibrous capsule with a cavity Special features for lubrication, movement and stability
Movable Joints “Movability” (mobility…?) is a relative term! Movement is always associated with restrictions Active movements – by muscles Movements due to other factors Shapes of bony surfaces Tensions in ligaments Other external factors (pelvic joints in childbirth) Passive movements in clinical examination
Fibrous Joints Sutures (“stitches”) Between flat bones of the skull Bone Periosteum Section (Magnified!) Surface view
Fibrous Joints Syndesmoses Inferior tibiofibular joint (Not shown here) Interosseous membranes Separation of compartments Additional areas for muscle attachments Some other ligaments… Gomphoses Tooth and bone “Peg-and-socket” R U
Cartilaginous Joints Synchondrosis – Hyaline cartilage Growth mechanism synostosis Between primary and secondary centres Between named bones (e.g. sphenoid + occipital) (Week 12 Histology!) Symphysis – White fibrocartilage WFC is deformable Partially movable joints Occasional cavities – ? Evolution of synovial joints Primary and secondary cartilaginous joints : terms best avoided. Functionally two distinct entities.
Synovial Joints “Freely movable”…? Freedom is relative! More movable than any other type…! Fibrous tissue bond, with a cavity
Synovial Joints – Basic Features The bones – articular surfaces Smooth… but not quite! Articular cartilage Fibrous capsule Ligaments Capsular thickening External Synovial membrane
Synovial Joints – Articular Cartilage Hyaline (WFC in membrane bones) No perichondrium Variable thickness Depends on the type of joint In curved surfaces Convex – thick in the centre Concave – thin in the centre
Synovial Joints – Capsule Etc Capsular attachment Thickening of capsule : “Intrinsic” ligaments Areas of strength / weakness Capsule may be loose in places Other ligaments (“extracapsular”) Synovial membrane and fluid
Synovial Joints – Subtypes Plane : Sliding movements (“Non-axial joint”) Hinge : Uniaxial (e.g. elbow) Ball-and-socket : Multiaxial (Shoulder, hip) Saddle : Two planes of movement + combinations Bicondylar : Two pairs of surfaces Pivot : Osseofibrous ring + rotating bone Nothing is perfect – do not expect geometrical shapes!
Two Types Illustrated Pivot joint – Osseofibrous ring and head of radius. Bicondylar joint – Knee Two pairs of articular surfaces
Bursae Muscles / tendons in close proximity – friction Bursa (Latin for purse!) Thin walled connective tissue bag Lining of synovial membrane Between joint capsule and tendon / muscle, bone and tendon / muscle, or between muscles / tendons. Bursitis – painful Some bursae communicate with joint cavity
Joint Stability Movement and stability – a compromise Factors in stability Bony configuration Capsule and ligaments Tendons and muscles Sometimes blend with capsule – rotator cuff
Nerves Rich sensory innervation Capsule, ligaments, periosteum Same nerves as those that supply muscles Joint pain Bony injuries Capsular / ligamentous injuries Synovial membrane And more…
Blood Vessels Rich blood supply All parts except cartilages Articular cartilage By diffusion through synovial fluid Blood vessels of surrounding areas (capsule, bone) Last Slide