Chapter 8 Joints

• Functions: Joints

  • Give the skeleton mobility

  • Hold the skeleton together
• Articulation


  Site where two or more bones meet
• Classification of joints: Function


  Is based of the amount of movement allowed by the joint
• The three functional classes of joints are...

  • Synarthroses: immovable

  • Amphiarthroses: slightly movable

  • Diarthroses: freely movable
• Classification of joints: Structural


  Focuses on the material binding bones together and whether or not a joint cavity is present
• The three structural classifications are...

  • Fibrous

  • Cartilaginous

  • Synovial
• Fibrous structural joints

  • The bones are joined by dense irregular fibrous connective tissue

  • There is no joint cavity

  • Most are immovable (synarthrotic)
• The three types of fibrous structural joints are..

  • Sutures

  • Syndesmoses

  • Gomphoses
• Fibrous structural joints: Sutures


  • Occur between the bones of the skull

  • Comprised of interlocking junctions completely filled with connective tissue fibers

  • Bind bones tightly together, but allow for growth during youth

  • In middle age, skull bones fuse and are called synostoses

  
• Functional and structural classifications of: Sutures

  • Synarthrotic

  • Fibrous
• Fibrous structural joints: Syndesmoses


  • Bones are connected by a fibrous tissue ligament

  • Movement varies from immovable to slightly variable

  • Examples include the connection between the tibia and fibula, and the radius and ulna at the distal end

  
• Functional and structural classifications of: Syndesmoses

  • Amphiarthrotic and synarthrotic

  • Fibrous
• Fibrous structural joints: Gomphoses


  • The peg-in-socket fibrous joint between a tooth and its alveolar socket

  • The fibrous connection is the periodontal ligament (surrounds the tooth)

  
• Functional and structural classifications of: Gomphoses

  • Synarthrotic

  • Fibrous
• Cartilaginous joints


  • Articulating bones are united by cartilage

  • Lack a joint cavity

  • Two types

  • synchondroses (hyaline cartilage)

  • symphyses (fibrocartilage)
• Cartilaginous joints: Synchondroses


  • A bar of hyaline cartilage unites the bones

  • All synchondroses are synarthrotic

  • Examples include

  • epiphyseal plates of children

  • joint between the costal cartilage of the first rib and the sternum

  
• Cartilaginous joints: Symphyses


  • Hyaline cartilage covers the articulating surface of the bone and is fused to intervening pad of fibrocartilage

  • Amphiarthrotic joints designed for strength and flexibility

  • Examples include intervertebral joints and the pubic symphysis of the pelvis

  
• Synovial joints


  • Those joints in which the articulating bones are separated by a fluid-containing joint cavity

  • All are freely movable diarthroses

  • Examples include all limbs, and most joints of the body
• Distinguishing features of synovial joints: Articular cartilage

  Hyaline cartilage

  
• Distinguishing features of synovial joints: Joint (synovial) cavity


  Small potential space

  
• Distinguishing features of synovial joints: Articular (joint) capsule


  • Outer fibrous capsule of dense irregular connective tissue

  • Inner synovial membrane of loose connective tissue

  
• Distinguishing features of synovial joints: Synovial fluid


  • Viscous slippery filtrate of plasma plus hyaluronic acid

  • Lubricates and nourishes articular cartilage

  
• Distinguishing features of synovial joints: Three possible types of reinforcing ligaments


  • Capsular (intrinsic): part of the fibrous capsule

  • Extracapsular: outside the capsule

  • Intracapsular: deep to capsule; covered by synovial membrane

  
• Distinguishing features of synovial joints: Rich nerve and blood vessel supply


  • Nerve fibers detect pain, monitor joint position and stretch

  • Capillary beds produce filtrate for synovial fluid

  
• Synovial joints: Friction-reducing structures

  • Bursae: flattened, fibrous sacs lined with synovial membranes and containing synovial fluid

  • common where ligaments, muscles, skin, tendons, or bones rub together

  • Tendon sheath: elongated bursa that wraps completely around a tendon

  
• Bursitis


  Inflammation (or swelling) of bursa
• Tendonitis


  Inflammation (or swelling) of tendon sheath
• The functional classification of joints is based on?

  Amount of movement allowed by the joint
• Sutures, which have their irregular edges of bone joined by short fibers of connective tissue, are an example of fibrous/cartilaginous joints

  Fibrous
• Every muscle of the body is attached to a bone or other connective tissue structure at two points. The origin/insertion is the more movable attachment

  Insertion
• The hip joint is an example of a ? synovial joint

  Ball-and-socket
• Movement of a limb away from the midline or median plane of the body in the frontal plane is known as?

  Abduction
• Functional and structural classifications of: Synchondroses

  • Synarthrotic

  • Cartilaginous
• Functional and structural classifications of: Symphyses

  • Amphiarthroses

  • Cartilaginous
• Which structure most directly acts directly to reduce friction during joint movement? Tendons/bursae

  Bursae; and tendon sheaths are fibrous sacs of synovial fluid that act as "ball bearings" around joints
• Which angular movement results from a combination of three other movements?

  Circumduction of the hip and shoulder joints is produced by a succession of flexion, abduction, extension (this movement forms a cone in space)
• Functional, structural, and movement classifications of: Plane

  • Diarthroses

  • Synovial

  • Uniaxial = gliding

  
• Functional, structural, and movement classifications of: Hinge

  • Diarthroses

  • Synovial

  • Uniaxial = flexion and extension

  
• Functional, structural, and movement classifications of: Pivot

  • Diarthroses

  • Synovial

  • Uniaxial = rotation

  
• Functional, structural, and movement classifications of: Condyloid

  • Diarthroses

  • Synovial

  • Biaxial = flexion, extension, adduction, and abduction