Joints

BIO 231

Anatomy and Physiology I

Classification of Joints

Structural

Fibrous, cartilaginous or synovial

Functional (amount of movement allowed)

Synarthroses - joints

Amphiarthroses - slightly movable joints

Diarthroses - freely moveable joints

Fibrous Joints

Bones joined by fibrous tissue - no joint cavity

Sutures - “seams” - as in the skull

Syndesmoses - bones connected by a ligament, cord or band of fibrous tissue

Distal end of tibia and fibula connected by a

Gomphoses - peg-in-pocket fibrous joint - tooth in the bony alveolar socket

Cartilaginous Joints

Synchondrosis - bar of hyaline cartilage - epiphyseal plates or costal cartilage of the first rib and the manubrium of the

Symphyses - Hyaline cartilage at the articular surface fuses to fibrocartilage - intervertebral joints and pubic symphysis of the pelvis

Cartilaginous Joints

Synovial Joints

Articular cartilage - covers opposing bone surfaces - cushions

Joint (synovial) cavity - just a potential space - contains a little fluid

Articular capsule - two layers

outer tough fibrous capsule of dense irregular connective tissue

Inner layer of synovial membrane - loose connective tissue

Synovial Joints

Synovbial fluid - derived largely by filtration from blood flowing through capillaries of the synovial membrane

A viscous egg-white consistency - due to hyaluronic acid secreted by the synovial

Reinforcing ligaments - called intrinsic or capsular ligaments

Synovial Joints

Synovial Joints

Fatty pads - between the fibrous capsule and the synovial membrane or bone

Mensci - articular discs - stabilize structure

Occur in the knee, jaw, sternoclavicular joint & radioulnar joint

Synovial Joints

Bursae - bags of lubricant to reduce friction between adjacent joint structures

Tendon sheath - elongated that wraps completely around a tendon subjected to friction, like a bun around a hot dog

Friction Reducing structures

Gliding Movements

Intercarpal and intertarsal joints & flat articular surfaces of the vertebrae

Angular Movements

Inc or dec the angle between two bones

May occur in any plane

Include flexion, extension, abduction , adduction and circumduction

Flexion and Extension

Dorsiflexion and Plantar Flexion of the Foot

Abduction, Adduction & Circumduction

Rotation

Supination & Pronation

Inversion and Eversion

Protraction and Retraction

Elevation and Depression

Opposition

Types of Synovial Joints

Plane joints - flat articular surfaces allow slippage or movements

Hinge joints - cylindrical projection of one bone fits into trough of another

Pivot joints - rounded end of one bone protrudes into sleeve or ring of another bone (could be ligaments)

joint between the atlas and the dens of the axis

Types of Joints

Condyloid or ellipsoidal Joints - oval articular surface of one bone fits into a complementary depression in another

radiocarpal & metacarpophalangeal

Saddle joints - resemble condyloid joints but freedom of movement

carpalmetacarpal joints

Types of Joints

Ball and socket joints - spherical or hemispherical head fits into cup-like socket of another bone

Hip and shoulder

Shoulder & Hip Joints

Knee Joint

Common Knee Injury

Vulnerable to horizontal blows - blocking and tackling in football

Vulnerable to blows

Anterior cruciate ligament (ACL) injuries - more common - runner changes direction quickly - twisting a hyperextended knee - soccer, basketball, softball, baseball

Sprains, Cartilage Injuries and Dislocations

Sprains - ligaments reinforcing a joint are stretched or torn

Cartilage injuries - most involve tearing the knee but overuse damage is becoming more common

Dislocations - bones forced out of alignment - may accompany sprains

must be reduced (returned to proper positions)

Bursitis & Tendonitis

Bursitis - Inflammation of the bursa by friction of blow

Tendonitis - inflammation of tendon sheaths - typically do to overuse

Arthritis

Over 100 inflammatory or degenerative diseases of the joints

Acute - due to bacterial invasion - treat with antibiotics

Osteoarthritis - chronic - breakdown of articular cartilage - due to age, use and destroying

Rheumatoid arthritis - chronic - autoimmune disease

Gouty arthritis - deposition of needle-shaped crystal of uric acid in soft tissue of joints