Joints and Movements

Functions of joints

Movement of body parts and stability of the skeleton

Synarthroses

Fibrous joints that are immovable

Amphiarthroses

Cartilaginous joints that are slightly movable

Diarthroses

Synovial joints that are freely movable

Fibrous joints

Immovable joints held together by fibrous connective tissue (ex: skull, teeth sockets)

Cartilaginous joints

Slightly movable joints united by cartilage and lacking a joint cavity

Synovial joints

Freely movable joints with a fluid-filled joint cavity

Ball-and-socket joint

Head of one bone fits into a cup-like socket (ex: hip, shoulder)

Pivot joint

Rounded bone rotates within a sleeve (ex: radius and ulna, atlas and axis)

Condyloid joint

Oval bone fits into a complementary depression (ex: wrist)

Saddle joint

Similar to condyloid joints but allows greater movement (ex: thumb)

Gliding joint

Flat or nearly flat bones slide over one another (ex: vertebrae, carpals, tarsals)

Hinge joint

Cylindrical projection fits into a trough-shaped surface (ex: elbow, knee)

Flexion

Decreasing the angle of a joint

Extension

Increasing the angle of a joint

Abduction

Movement away from the body’s midline

Adduction

Movement toward the body’s midline

Rotation

Movement around a central axis

Circumduction

Circular movement of a limb

Supination

Lateral rotation of the forearm (“carry a cup of soup”)

Pronation

Medial rotation of the forearm (“punch something”)

Eversion

Soles of the feet point outward

Inversion

Soles of the feet point toward the midline

Protraction

Sliding a body part forward

Retraction

Sliding a body part backward

Elevation

Raising a body part upward

Depression

Lowering a body part downward

Dorsiflexion

Toes up, heel on the ground

Plantarflexion

Toes down, heels lifted

Bursitis

Inflammation of a bursa causing pain and swelling

Sprain

Stretching or tearing of ligaments

Osteoarthritis (OA)

Joint pain, stiffness, and swelling due to joint damage

Rheumatoid arthritis (RA)

Autoimmune disease causing joint tenderness and systemic symptoms

Gout

Uric acid crystal buildup in joints causing inflammation and pain