Transcript Ch. 8 Joints

PowerPoint® Lecture Slides
prepared by
Janice Meeking,
Mount Royal College
CHAPTER
8
Joints: Part A
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Joints (Articulations)
• Articulation—site where two or more bones
meet
• Functions of joints:
• Give skeleton mobility
• Hold skeleton together
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Classification of Joints
• There are two ways to classify joints:
Functional and Structural
• Functional Classification of joints is based on
amount of movement allowed by the joint
• Synarthroses—immovable
• Amphiarthroses—slightly movable
• Diarthroses—freely movable
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Classification of Joints
• Structural Classification of Joints - Based on
material binding bones together and whether
or not a joint cavity is present (Fibrous,
Cartilagenous, Synovial)
• Three types of fibrous joints:
• Sutures-occur only between skull bones;
jagged articulations w/ short fibers btwn.
• Syndesmoses- bones connected by
ligaments, cords/bands of CT
• Gomphoses –a peg in socket joint; the only
example is a tooth in its bony alveolar socket
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(a)
Suture
Joint held together with very short,
interconnecting fibers, and bone edges
interlock. Found only in the skull.
Suture
line
Dense
fibrous
connective
tissue
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Figure 8.1a
(b) Syndesmosis
Joint held together by a ligament.
Fibrous tissue can vary in length, but
is longer than in sutures.
Fibula
Tibia
Ligament
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Figure 8.1b
(c) Gomphosis
“Peg in socket” fibrous joint. Periodontal
ligament holds tooth in socket.
Socket of
alveolar
process
Root of
tooth
Periodontal
ligament
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Figure 8.1c
Classification of Joints
• Cartilagenous Joints:
• Two types of cartilagenous joints
• Synchondroses- a bar of hyaline cartilage
unites bone; mostly all are synarthrotic; (ex.
epiphyseal plates in children)
• Symphyses – articular surfaces of bones
covered with hyaline which is fused to an
intervening pad of fibrocartilage (ex.
intervertebral discs)
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(a)
Synchondroses
Bones united by hyaline cartilage
Epiphyseal
plate (temporary
hyaline cartilage
joint)
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Sternum
(manubrium)
Joint between
first rib and
sternum
(immovable)
Figure 8.2a
(b)
Symphyses
Bones united by fibrocartilage
Body of vertebra
Fibrocartilaginous
intervertebral
disc
Hyaline cartilage
Pubic symphysis
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Figure 8.2b
Synovial Joints
General Structures of Synovial Joints
• Articular cartilage: pad of hyaline cartilage on
ends of long bones
• Joint (synovial) cavity: small potential space;
contains synovial fluid
• A double-layered joint capsule : an outer fibrous
capsule (dense irregular CT) and an inner
synovial membrane (loose CT)
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Synovial Joints
General Structures of Synovial Joints
• Synovial fluid- a viscous fluid occupying joint cavity;
lubricates and nourishes articular cartilage
• May have wedges of fibrocartilage separating the
articular surfaces called: menisci
• Fibrous (bursae) lined with: synovial membrane contains
synovial fluid and acts as friction reducing ball bearings
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Ligament
Joint cavity
(contains
synovial fluid)
Articular (hyaline)
cartilage
Fibrous
capsule
Articular
Synovial
capsule
membrane
Periosteum
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Figure 8.3
Subacromial
bursa
Cavity in
bursa containing
synovial fluid
Humerus
resting
Humerus
moving
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Figure 8.4b
Types of Synovial Joints
• Plane-Nonaxial joints, short gliding movements
• Hinge -Uniaxial joints, flexion and extension only
• Pivot – Uniaxial joints, rotation
• Condyloid - Biaxial joints, permit all angular movements
• Saddle – Biaxial, more movement than condyloid
• Ball and socket - Multiaxial joints; the most freely moving
synovial joints
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f
Nonaxial
Uniaxial
Biaxial
Multiaxial
c
b
a Plane joint (intercarpal joint)
a
e
d
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Figure 8.7a
f
Nonaxial
Uniaxial
Biaxial
Multiaxial
c
b Hinge joint (elbow joint)
b
a
e
d
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Figure 8.7b
f
Nonaxial
Uniaxial
Biaxial
Multiaxial
c
b
c Pivot joint (proximal radioulnar joint)
a
e
d
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Figure 8.7c
f
Nonaxial
Uniaxial
Biaxial
Multiaxial
c
b
d Condyloid joint
(metacarpophalangeal joint)
a
e
d
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Figure 8.7d
f
Nonaxial
Uniaxial
Biaxial
Multiaxial
c
e Saddle joint (carpometacarpal joint
of thumb)
b
a
e
d
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Figure 8.7e
f
Nonaxial
Uniaxial
Biaxial
Multiaxial
c
b
f Ball-and-socket joint (shoulder joint)
a
e
d
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Figure 8.7f
Common Joint Injuries
• Sprains - Ligaments are stretched or torn; slow to repair
themselves
• Cartilage tears - Due to compression and shear stress,
fragments may cause joint to lock or bind; Cartilage rarely
repairs itself
• Dislocations – Bones are forced out of alignment
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Torn
meniscus
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Figure 8.14
Inflammatory and Degenerative Conditions
• Bursitis - Inflammation of a bursa, usually
caused by a blow or friction
• Tendonitis - Inflammation of tendon sheaths
typically caused by overuse
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Arthritis
• Symptoms; pain, stiffness, and swelling of a
joint
• Acute forms: caused by bacteria, treated with
antibiotics
• Chronic forms: osteoarthritis, rheumatoid
arthritis, and gouty arthritis
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Gliding Movements
• One flat bone surface glides or slips over
another similar surface
• Examples:
• Intercarpal joints
• Intertarsal joints
• Between articular processes of vertebrae
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Gliding
(a) Gliding movements at the wrist
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Figure 8.5a
Angular Movements
• Movements that occur along the sagittal
plane:
• Flexion—decreases the angle of the joint
• Extension— increases the angle of the joint
• Hyperextension—excessive extension beyond
normal range of motion
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Hyperextension
Extension
Flexion
(b) Angular movements: flexion, extension, and
hyperextension of the neck
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Figure 8.5b
Extension
Hyperextension
Flexion
(c) Angular movements: flexion, extension, and
hyperextension of the vertebral column
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Figure 8.5c
Flexion
Extension
Flexion
Extension
(d) Angular movements: flexion and extension at the
shoulder and knee
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Figure 8.5d
Angular Movements
• Movements that occur along the frontal plane:
• Abduction—movement away from the midline
• Adduction—movement toward the midline
• Circumduction—flexion + abduction +
extension + adduction of a limb so as to
describe a cone in space
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Abduction
Adduction
Circumduction
(e) Angular movements: abduction, adduction, and
circumduction of the upper limb at the shoulder
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Figure 8.5e
Rotation
• The turning of a bone around its own long axis
• Examples:
• Between C1 and C2 vertebrae
• Rotation of humerus and femur
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Rotation
Lateral
rotation
Medial
rotation
(f) Rotation of the head, neck, and lower limb
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Figure 8.5f
Special Movements
• Movements of radius around ulna:
• Supination - lateral rotation of hands
• Pronation - medial rotation of hands
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Pronation
(radius
rotates
over ulna)
Supination
(radius and
ulna are
parallel)
(a) Pronation (P) and supination (S)
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Figure 8.6a
Special Movements
• Movements of the foot:
• Dorsiflexion - upward movement
• Plantar flexion - downward movement
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Dorsiflexion
Dorsiflexion
Plantar
flexion
Plantar
flexion
(b) Dorsiflexion and plantar flexion
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Figure 8.6b
Special Movements
• Movements of the foot:
• Inversion - turn sole medially
• Eversion - turn sole laterally
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Inversion
Eversion
(c) Inversion and eversion
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Figure 8.6c
Special Movements
• Movements in a transverse plane:
• Protraction- anterior movement
• Retraction-posterior movement
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Protraction
of mandible
Retraction
of mandible
(d) Protraction and retraction
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Figure 8.6d
Special Movements
• Elevation - lifting a body part superiorly
• Depression - moving a body part inferiorly
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Elevation
of mandible
Depression
of mandible
(e) Elevation and depression
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Figure 8.6e
Special Movements
• Opposition of the thumb -Movement in the
saddle joint so that the thumb touches the tips
of the other fingers
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Opposition
(f) Opposition
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Figure 8.6f