Ch08 a.joint

Human
Anatomy
& Physiology
SEVENTH EDITION
Elaine N. Marieb
Katja Hoehn
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
PowerPoint® Lecture Slides
prepared by Vince Austin,
Bluegrass Technical
and Community College
C H A P T E R
8
Joints
P A R T A

Joints (Articulations)
 Weakest parts of the skeleton
 Articulation – site where two or more bones meet
 Functions of joints
 Give the skeleton mobility
 Hold the skeleton together

Classification of Joints: Structural
 Structural classification focuses on the material
binding bones together and whether or not a joint
cavity is present
 The three structural classifications are:
 Fibrous
 Cartilaginous
 Synovial

Classification of Joints: Functional
 Functional classification is based on the amount of
movement allowed by the joint
 The three functional classes of joints are:
 Synarthroses – immovable
 Amphiarthroses – slightly movable
 Diarthroses – freely movable

Fibrous Structural Joints
 The bones are joined by fibrous tissues
 There is no joint cavity
 Most are immovable
 There are three types – sutures, syndesmoses, and
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

Fibrous Structural Joints: Sutures
Figure 8.1a

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

Fibrous Structural Joints: Syndesmoses
Figure 8.1b

Fibrous Structural Joints: Gomphoses
 The peg-in-socket fibrous joint between a tooth
and its alveolar socket
 The fibrous connection is the periodontal ligament

Cartilaginous Joints
 Articulating bones are united by cartilage
 Lack a joint cavity
 Two types – synchondroses and symphyses

Cartilaginous Joints: Synchondroses
 A bar or plate 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: Synchondroses
Figure 8.2a, b

Cartilaginous Joints: Symphyses
 Hyaline cartilage covers the articulating surface of
the bone and is fused to an intervening pad of
fibrocartilage
 Amphiarthrotic joints designed for strength and
flexibility
 Examples include intervertebral joints and the
pubic symphysis of the pelvis

Cartilaginous Joints: Symphyses
Figure 8.2c

Synovial Joints
 Those joints in which the articulating bones are
separated by a fluid-containing joint cavity
 All are freely movable diarthroses
 Examples – all limb joints, and most joints of the
body

Synovial Joints: General Structure
 Synovial joints all have the following
 Articular cartilage
 Joint (synovial) cavity
 Articular capsule
 Synovial fluid
 Reinforcing ligaments

Synovial Joints: General Structure
Figure 8.3a, b

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

Synovial Joints: Friction-Reducing Structures
Figure 8.4

Synovial Joints: Stability
 Stability is determined by:
 Articular surfaces – shape determines what
movements are possible
 Ligaments – unite bones and prevent excessive or
undesirable motion

Synovial Joints: Stability
 Muscle tone is accomplished by:
 Muscle tendons across joints acting as stabilizing
factors
 Tendons that are kept tight at all times by muscle
tone

Synovial Joints: Movement
 The two muscle attachments across a joint are:
 Origin – attachment to the immovable bone
 Insertion – attachment to the movable bone
 Described as movement along transverse, frontal,
or sagittal planes

Synovial Joints: Range of Motion
 Nonaxial – slipping movements only
 Uniaxial – movement in one plane
 Biaxial – movement in two planes
 Multiaxial – movement in or around all three
planes

Gliding Movements
 One flat bone surface glides or slips over another
similar surface
 Examples – intercarpal and intertarsal joints, and
between the flat articular processes of the vertebrae

Angular Movement
 Flexion — bending movement that decreases the
angle of the joint
 Extension — reverse of flexion; joint angle is
increased
 Dorsiflexion and plantar flexion — up and down
movement of the foot

Angular Movement
 Abduction — movement away from the midline
 Adduction — movement toward the midline
 Circumduction — movement describes a cone in
space

Gliding Movement
Figure 8.5a

Angular Movement
Figure 8.5b

Angular Movement
Figure 8.5c, d

Angular Movement
Figure 8.5e, f

Rotation
 The turning of a bone
around its own long axis
 Examples
 Between first two
vertebrae
 Hip and shoulder joints
Figure 8.5g

Special Movements
 Supination and pronation
 Inversion and eversion
 Protraction and retraction
 Elevation and depression
 Opposition

Special Movements
Figure 8.6a

Special Movements
Figure 8.6b

Special Movements
Figure 8.6c

Special Movements
Figure 8.6d

Special Movements
Figure 8.6e

Ch08 a.joint

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