Classification of Joints and Ligaments

Study Notes

Non-axial motion: Bones slide in linear movements (e.g., vertebrocostal, sacroiliac, intercarpal joints).
Uniaxial motion: Movement occurs in one plane (e.g., finger joints, elbow, knee).
Biaxial motion: Movement occurs in two planes (e.g., metacarpophalangeal joint, occipital condyles to atlas).
Multi-axial motion: Movement occurs in three planes (e.g., shoulder joint, hip joint).

Sutures: Immovable fibrous joints found in the skull.
Syndesmoses: Slightly movable fibrous joints where bones are held together by ligaments (e.g., distal tibiofibular joint).
Gomphoses: Specialized fibrous joints that anchor teeth to their sockets (e.g., periodontal ligament).

Intrinsic ligaments: Also known as capsular ligaments, these are thickenings within the joint capsule, forming parallel bundles of fibers.
Extrinsic ligaments: These ligaments are separate from the joint capsule, potentially passing outside (extracapsular) or inside (intracapsular) the capsule.

Joints form during embryonic development in conjunction with bone formation and growth.
Mesenchyme, the embryonic tissue, differentiates into all bones, cartilages, and connective tissues of the body.

Sprain: Stretching or tearing of a ligament across the joint capsule.
Dislocation (luxation): Occurs when reinforcing structures fail to protect a joint from extreme stresses, causing the articulating surfaces to be forced out of position.
Subluxation: Partial dislocation.
Bursitis: Inflammation of the bursa.
Tendonitis: Inflammation of the tendon.
Synovitis: Inflammation of the synovial membrane.
Osteopenia and osteoporosis: Inadequate ossification of bone, starting around age 30-40. Osteopenia is the initial decline in bone mass, followed by osteoporosis if the reduction is significant.
Arthritis: Inflammatory or degenerative joint disease characterized by thickened synovial membranes and decreased fluid production, leading to friction and pain.

Osteoarthritis (degenerative arthritis): Affects individuals over 60, resulting from wear and tear or genetic collagen issues.
Rheumatoid arthritis: Autoimmune disease affecting joints on both sides of the body, typically wrists, fingers, knees, feet, and ankles. More common in middle age and women.
Gouty arthritis: Caused by high uric acid levels in the blood, forming crystals in joints (often the big toe), leading to sudden pain, stiffness, and swelling. More common in men.

Bulging disc: Compression of the nucleus pulposus distorts the anulus fibrosus.
Herniated disc: The nucleus pulposus protrudes through the anulus fibrosus into the vertebral canal.