joints come in many types. joints (articulations) functions of joints classifying joints: functional...
TRANSCRIPT
Joints Come in Many Types
Joints (Articulations) • Functions of joints
• Classifying Joints: Functional or Structural
• Naming Movements of Bones Around Joints
• Types of Joints Based on Movement
• Selected Key Joints: Shoulder, Elbow, Hip, Knee
• Joint Injuries
• Chronic Joint Conditions: Arthritis
Joints (Articulations)• Definition: site where two or more bones meet
• Functions of joints:
• Give skeleton mobility
• Hold skeleton together
• Joint classification
• Structural classification (material binding bones together and whether or not a joint cavity is present)
• Fibrous joints (sutures, syndesmoses, gomphoses)
• Cartilaginous
• Synovial
• Functional classification (amount of movement allowed by the joint)
• Synarthroses—immovable
• Amphiarthroses—slightly movable
• Diarthroses—freely movable
Fibrous Joints
• Bones joined by dense fibrous connective tissue
• No joint cavity
• Most are synarthrotic (immovable)
• Three types:
• Sutures
• Syndesmoses
• Gomphoses
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Densefibrousconnectivetissue
Sutureline
(a) Suture
Joint held together with very short,interconnecting fibers, and bone edges
interlock. Found only in the skull.• Rigid, interlocking joints containing short connective tissue fibers
• Allow for growth during youth
• In middle age, sutures ossify and are called synostoses
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Fibula
Tibia
Ligament
(b) Syndesmosis
Joint held together by a ligament.Fibrous tissue can vary in length, but
is longer than in sutures.
• Bones connected by ligaments (bands of fibrous tissue)
• Movement varies from immovable to slightly movable
• Examples:
• Synarthrotic distal tibiofibular joint
• Diarthrotic interosseous connection between radius and ulna
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Root oftooth
Socket ofalveolarprocess
Periodontalligament
(c) Gomphosis
“Peg in socket” fibrous joint. Periodontalligament holds tooth in socket.
• Peg-in-socket joints of teeth in alveolar sockets
• Fibrous connection is the periodontal ligament
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Joints (Articulations)• Definition: site where two or more bones meet
• Functions of joints:
• Give skeleton mobility
• Hold skeleton together
• Joint classification
• Structural classification (material binding bones together and whether or not a joint cavity is present)
• Fibrous joints (sutures, syndesmoses, gomphoses)
• Cartilaginous
• Synovial
• Functional classification (amount of movement allowed by the joint
• Synarthroses—immovable
• Amphiarthroses—slightly movable
• Diarthroses—freely movable
Cartilaginous Joints
• Bones united by cartilage
• No joint cavity
• Two types:
• Synchondroses
• Symphyses
Copyright © 2010 Pearson Education, Inc.
Types of Cartilaginous Joints
(all are synarthrotic- don’t move)
(are strong, flexible amphiarthroses)
Hyaline cartilage that covers articular surfaces
Copyright © 2010 Pearson Education, Inc.
Joints (Articulations)• Definition: site where two or more bones meet
• Functions of joints:
• Give skeleton mobility
• Hold skeleton together
• Joint classification
• Structural classification (material binding bones together and whether or not a joint cavity is present)
• Fibrous joints (sutures, syndesmoses, gomphoses)
• Cartilaginous
• Synovial
• Functional classification (amount of movement allowed by the joint
• Synarthroses—immovable
• Amphiarthroses—slightly movable
• Diarthroses—freely movable
Synovial Joints (Diarthrotic (freely movable)- most of body’s joints)
Distinguishing features:
1. Articular cartilage: hyaline cartilage
2. Joint (synovial) cavity: small potential space
3. Articular (joint) capsule
• Outer fibrous capsule of dense irregular connective tissue
• Inner synovial membrane of loose connective tissue (type of integument)
4. Synovial fluid
• Viscous slippery filtrate of plasma + hyaluronic acid
• Lubricates and nourishes articular cartilage
5. 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
6. Rich nerve and blood vessel supply
• Nerve fibers detect pain, monitor joint position and stretch
• Capillary beds produce filtrate for synovial fluid
Bone A
Bone B
Synovial Joints: Friction-Reducing Structures• Bursae
• Flattened, fibrous sacs lined with synovial membranes
• Contain synovial fluid
• Commonly act as “ball bearings” where ligaments, muscles, skin, tendons, or bones rub together
• Inflammation from overuse or stress of joint causes bursitis
• Tendon sheath
• Elongated bursa that wraps completely around a tendon
• Inflammation from stress or overuse causes tendonitis
Synovial Joints: Stabilization, Movement, Range of Motion
• Stabilizing Factors
• Shapes of articular surfaces (minor role)
• Ligament number and location (limited role)
• Muscle tone, which keeps tendons that cross the joint taut
• Extremely important in reinforcing shoulder and knee joints and arches of the foot
• Movement
• Muscle attachments across a joint (will learn details when we learn muscles)
• Origin—attachment to the immovable bone
• Insertion—attachment to the movable bone
• Muscle contraction causes the insertion to move toward the origin
• Movements occur along transverse, frontal, or sagittal planes
• Range of Motion (don’t need to know)
• Nonaxial—slipping movements only
• Uniaxial—movement in one plane
• Biaxial—movement in two planes
• Multiaxial—movement in or around all three planes
Joints (Articulations) • Functions of joints
• Classifying Joints: Functional or Structural
• Naming Movements of Bones Around Joints
• Types of Joints Based on Movement
• Selected Key Joints: Shoulder, Elbow, Hip, Knee
• Joint Injuries
• Chronic Joint Conditions: Arthritis
Movements at Synovial Joints
1. Gliding2. Angular movements
• Flexion, extension, hyperextension• Abduction, adduction• Circumduction
3. Rotation• Medial and lateral rotation
4. Angular movements:• Flexion, extension, hyperextension• Abduction, adduction
5. Other movements• Dorsiflexion, plantar flexion• Inversion, eversion• Protraction, retraction• Elevation, depression• Opposition
Copyright © 2010 Pearson Education, Inc. Figure 8.5a
Gliding
(a) Gliding movements at the wrist
Copyright © 2010 Pearson Education, Inc. Figure 8.5b
(b) Angular movements: flexion, extension, and hyperextension of the neck
Hyperextension Extension
Flexion
Copyright © 2010 Pearson Education, Inc. Figure 8.5c
Hyperextension Flexion
Extension
(c) Angular movements: flexion, extension, andhyperextension of the vertebral column
Copyright © 2010 Pearson Education, Inc. Figure 8.5d
Extension
Extension
Flexion
Flexion
(d) Angular movements: flexion and extension at theshoulder and knee
Copyright © 2010 Pearson Education, Inc. Figure 8.5e
Abduction
Adduction
(e) Angular movements: abduction, adduction, andcircumduction of the upper limb at the shoulder
Circumduction
Copyright © 2010 Pearson Education, Inc. Figure 8.5f
Lateralrotation
Medialrotation
Rotation
(f) Rotation of the head, neck, and lower limb
Copyright © 2010 Pearson Education, Inc. Figure 8.6a
Supination(radius and ulna are parallel)
(a) Pronation (P) and supination (S)
Pronation(radius rotatesover ulna)
Copyright © 2010 Pearson Education, Inc. Figure 8.6b
Dorsiflexion
Plantar flexion
Dorsiflexion
Plantar flexion
(b) Dorsiflexion and plantar flexion
Copyright © 2010 Pearson Education, Inc. Figure 8.6c
EversionInversion
(c) Inversion and eversion
Copyright © 2010 Pearson Education, Inc. Figure 8.6d
Protractionof mandible
Retractionof mandible
(d) Protraction and retraction
Copyright © 2010 Pearson Education, Inc. Figure 8.6e
Elevationof mandible
Depressionof mandible
(e) Elevation and depression
Copyright © 2010 Pearson Education, Inc. Figure 8.6f
(f) Opposition
Opposition