Exam 5 Part 1 Flashcards
Joints
also called articulations: sites where two or more bones meet
Functions of joints
give skeleton mobility and hold skeleton together
Structural
1.three types based on what material binds the joints and whether a cavity is present
- Fibrous
- Cartilaginous
- Synovial
Functional
2.three types based on movement joint allows
- Synarthroses: immovable joints
- Amphiarthroses: slightly movable joints
- Diarthroses: freely movable joints
Fibrous Joints
- Bones joined by dense fibrous connective tissue
- No joint cavity
- Most are immovable (synarthroses)
–Depends on length of connective tissue fibers
Three types of fibrous joints
–Sutures
–Syndesmoses
–Gomphoses
Suture
Synesmosis
Gomphosis
Cartilaginous Joints
- Bones united by cartilage
- Like fibrous joints, have no joint cavity
- Not highly movable
- Two types
–Synchondroses and Symphyses
Synchondroses
- A bar or plate of hyaline cartilage unites bones
- Almost all are synarthrotic (immovable)
- Examples
–Temporary epiphyseal plate joints
•Become synostoses after plate closure
–Cartilage of 1st rib with manubrium of sternum
Symphyses
•Fibrocartilage unites bone in symphysis joint
–Hyaline cartilage also present as articular cartilage on bony surfaces
- Symphyses are strong, amphiarthrotic (slightly movable) joints
- Examples: Intervertebral joints, pubic symphysis
Synovial Joints
- Bones separated by fluid-filled joint cavity
- All are diarthrotic (freely movable)
- Include almost all limb joints
- Characteristics of synovial joints
–Have six general features
–Have bursae and tendon sheaths associated with them
–Stability is influenced by three factors
–Allow several types of movements
–Classified into six different types
•Synovial joints have six general features:
- Articular cartilage:
1.consists of hyaline
cartilage covering ends of bones
•Prevents crushing of bone ends
- Joint (synovial) cavity:
small, fluid-filled
potential space that is unique to synovial joints
- Articular (joint) capsule:
3.two layers thick
- External fibrous layer: dense irregular connective tissue
- Inner synovial membrane: loose connective tissue that makes synovial fluid
- Synovial fluid
4.viscous, slippery filtrate of
plasma and hyaluronic acid
- Lubricates and nourishes articular cartilage
- Contains phagocytic cells to remove microbes and debris
- Different types of reinforcing ligaments
- Capsular: thickened part of fibrous layer
- Extracapsular: outside the capsule
- Intracapsular: deep to capsule; covered by synovial membrane
- Nerves and blood vessels
- Nerves detect pain; monitor joint position and stretch
- Capillary beds supply filtrate for synovial fluid
•Three factors determine stability of joints to prevent dislocations:
1.Shape of articular surface (minor role)
•Shallow surfaces less stable than ball-and-socket
2.Ligament number and location (limited role)
•The more ligaments, the stronger the joint
3.Muscle tone keeps tendons taut as they cross joints (most important)
•Extremely important in reinforcing shoulder and knee joints and arches of the foot
•All muscles attach to bone or connective tissue at no fewer than two points
–Origin: attachment to immovable bone
–Insertion: attachment to movable bone
•Range of motion allowed by synovial joints
–Nonaxial: slipping movements only
–Uniaxial: movement in one plane
–Biaxial: movement in two planes
–Multiaxial: movement in or around all three planes
•Three general types of movements
–Gliding
–Angular movements
–Rotation