Skeletal System Joint Notes

Joints perform two functions Hold bones together Allow rigid skeleton some flexibility so movement can occur.

Structural or Functional?? Structure – presence of CT fibers, cartilage or a joint cavity between bones. Structure – presence of CT fibers, cartilage or a joint cavity between bones. –Examples – fibrous, cartilaginous & synovial –Function – amount of movement at the joint »Immovable, slightly movable or freely moving

Fibrous Joints(Synarthrosis)

Fibrous Joints 1. Joined by fibrous tissue(CT) 1. Joined by fibrous tissue(CT) 2. No joint cavity 2. No joint cavity 3. Most permit no movement 3. Most permit no movement 4. Lie between bones that closely contact one another 4. Lie between bones that closely contact one another

Fibrous Joint Examples Sutures, space between tibia & fibula Sutures, space between tibia & fibula

Cartilaginous Joints(Amphiarthrosis)

Cartilaginous Joints 1 No joint cavity 2. Fibro cartilage (shock absorber), hyaline 3. Slightly movable 4. Symphyses – growing together, bones connected by a flat disc of fibro cartilage 5. Synchondroses – hyaline cartilage, epiphyseal plates, long bones

Cartilaginous Joint Examples

Synovial Joints (Diarthrosis)

Synovial Joints 1. Most common, most complex 1. Most common, most complex 2. Articulating bone ends separated by a jt. Cavity with synovial fluid. 3. Freely movable 4. Mobility varies

Synovial Joints cont. 5. Joint surfaces enclosed by two layer capsule 5. Joint surfaces enclosed by two layer capsule 6. Inner layer smooth CT membrane with lubricating fluid. Outer layer - dense fibrous CT. 6. Inner layer smooth CT membrane with lubricating fluid. Outer layer - dense fibrous CT. 7. Hyaline cartilage covers the surfaces 7. Hyaline cartilage covers the surfaces 8. Ex. knee & shoulder 8. Ex. knee & shoulder

Synovial Joint Diagram

Types of synovial joints 1. Ball & socket 1. Ball & socket –Ball shaped head fits into caplike depression –Multi – axial –Wider range of motion than any other –Shoulder & hip

Condyloid 1.oval shaped condyle fits into elliptical cavity of another 2. Biaxial 3. Radio carpal (wrist) and metacarpophalangeal

Gliding 1. Articulating surfaces flat or slightly curved 2. Sliding movements in one or two planes 3. Intercarpal & intertarsal jts.

Hinge 1. Rounded process of one bone fits into concave surface of another 2. Uniaxial 3. Resembles hinge of a door 4. Elbow & interphalangeal jts.

Pivot 1. Rounded or cylindrical surface rotates within a ring formed of bone and fibrous tissue 2. Uniaxial rotation 3. Proximal ends of radius and ulna, C1 – C2

Saddle 1. Articulating surfaces have both concave & convex surfaces 2. Biaxial 3. Metacarpal & trapezium

Meniscus Flattened shock absorbing pads of fibro cartilage Flattened shock absorbing pads of fibro cartilage Medial & lateral Medial & lateral

Meniscus

Bursae Fluid filled sac, lined with synovial membrane Fluid filled sac, lined with synovial membrane Located between the skin and underlying bony prominence Located between the skin and underlying bony prominence Aids in movement of tendons that pass over bony parts Aids in movement of tendons that pass over bony parts Patella & olecranon Patella & olecranon

Bursae

Burase