Untitled Quiz

Classification of Joints

• Joints categorized by motion: Synarthrosis (no movement), Amphiarthrosis (limited movement), and Diarthrosis (freely movable).
• Structural classification includes Fibrous joints (no joint space), Cartilaginous joints (cartilage, no joint space), and Synovial joints (joint space filled with fluid).

Synarthrosis

• Characterized by no movement and high stability.

Amphiarthrosis

• Allows slight movement while maintaining stability.

Diarthrosis

• Offers a wide range of movement but is less stable.

Fibrous Joints

• Composed mainly of dense, regular collagenous connective tissue with no joint space; can be synarthrosis or amphiarthrosis.

Cartilaginous Joints

• Joints held together by cartilage, also lacking joint space; can be synarthrosis or amphiarthrosis.

Synovial Joints

• Feature hyaline cartilage on the bone surface, a fluid-filled joint cavity, allowing for diarthrosis movements.

Specific Types of Fibrous Joints

• Sutures: Immovable joints in the skull that provide stability and protect the brain.
• Gomphoses: Immovable joints between teeth and jaw, secured by the periodontal ligament.
• Syndesmoses: Joints with slight movement, such as between tibia and fibula, joined by interosseous membranes.

Cartilaginous Joint Types

• Synchondroses: Bones connected by hyaline cartilage, allowing synarthrosis; important during growth (e.g., epiphyseal plates).
• Symphyses: Fibrocartilaginous joints allowing amphiarthrosis, found in intervertebral joints and pubic symphysis.

Synovial Fluid

• A thick lubricant with three key functions:
  • Reduces friction.
  • Transports nutrients and waste in avascular joints.
  • Absorbs shock to distribute stress during movement.

Articular Cartilage

• Avascular layer covering the ends of bones in joints, reducing friction and wear.

Synovial Joint Components

• Include adipose tissue, nerves, and blood vessels, contributing to joint function and stability.

Ligaments and Tendons

• Ligaments: Connective tissues linking bone to bone, providing strength and stability to joints.
• Tendons: Connect muscle to bone; cross joints and stabilize during muscle contraction.

Bursae and Tendon Sheaths

• Bursae: Fluid-filled structures reducing friction in joints.
• Tendon Sheaths: Protective enclosures around tendons as they move across joints.

Functional Classes of Synovial Joints

• Classified by axis of movement: Nonaxial (no axis), Uniaxial (one axis), Biaxial (two axes), and Multiaxial (three axes).

Types of Movements at Synovial Joints

• Gliding Movements: Nonaxial sliding actions.
• Angular Movements: Affect joint angles, including flexion (decrease), extension (increase), and more.
• Rotation: One bone rotates around its longitudinal axis.

Special Joint Movements

• Include opposition, reposition, elevation, depression, protraction, retraction, inversion, and eversion, allowing complex actions.

Types of Synovial Joints

• Plane Joints: Nonaxial gliding joints (e.g., between carpals).
• Hinge Joints: Uniaxial joints allowing flexion and extension (e.g., elbow, knee).
• Pivot Joints: Uniaxial joints permitting rotation (e.g., between atlas and axis of spine).
• Condylar (Ellipsoid) Joints: Biaxial joints allowing movement in two planes (e.g., metacarpals).
• Saddle Joints: Biaxial with both concave and convex surfaces (e.g., thumb).
• Ball and Socket Joints: Multiaxial joints (e.g., shoulder and hip).

Specific Hinge Joints

• Elbow: Stable with two articulations and reinforced by three strong ligaments.
• Knee: Comprises various ligaments and menisci for stability and shock absorption.
• Hip: Highly stable, supported by a complex structure of ligaments and a fibrocartilaginous labrum.

Hip Joint Ligaments

• Acetabular Labrum: Stabilizes femoral head.
• Retinacular Fibers: Reinforce the joint capsule.
• Iliofemoral, Ischiofemoral, and Pubofemoral Ligaments: Provide additional joint support and stability.