Transcript Document

Joints
Chapter 5
Joints
• Articulation: sites where two or more bones meet
(also called “arthrosis”)
• Functions
• Hold bones together securely
• Give skeleton mobility
• Classification
• Functionally: amount of movement joint allows
• Synarthroses
• Amphiarthroses
• Diarthroses
• Structurally: type of binding connective tissue;
presence/absence of synovial cavity
•
•
•
•
Fibrous
Cartilaginous
Synovial
Page 168, fig 5.30
Functional Classification
• Synarthrosis
• Immoveable joint
• Can become synostosis (bony joint)
• Ex: sutures of skull
Functional Classification
• Amphiarthrosis
• Slightly moveable joint
• Ex: tibiofibular joint; slight flexibility to protect
the bones of the joint but injured if moved too far
Functional Classification
• Diarthrosis
• Freely moveable joint
• All synovial joints
(functional and structural
categories align!)
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Structural Classification
Structural Classification
• Fibrous Joints
• United by fibrous connective tissue
• No synovial cavity
• Most are functionally classified as synarthroses
(immoveable)
• Ex: sutures of skull
Types of Fibrous Joints
• Sutures
• Between bones of skull (only)
• Amphiarthroses as fontanels
• Become synarthroses (no movement)
• Can become synostoses (bony joint)
• Unique to the individual like fingerprints
Types of Fibrous Joints
• Syndesmosis
• More distance
• Fibrous connective tissue
in sheet (interosseous
membrane) or bundle
(ligament)
• Functionally classified as
amphiarthroses
• Ex: tibiofibular joint
Types of Fibrous Joints
• Gomphosis (dentoalveolar)
• Cone-shaped peg in socket
• Functionally classified as synarthrosis
• Only joint between
teeth and bone
Structural Classification
• Cartilaginous Joints
• Bone ends connected by cartilage
• Can be functionally classified as amphiathrosis
(slightly moveable) or synarthrosis (immoveable)
• No synovial cavity
• Ex: pubic symphysis, intervertebral joints, epiphyseal
plates
Types of Cartilaginous Joints
• Synchondrosis
• Hyaline cartilage
• Synarthrosis
• Ex: growth plates
-epiphyseal plates
& joint between
first rib and
sternum
• Become
synostoses
when grown
Types of Cartilaginous Joints
• Symphysis
• Fibrocartilage
• Found in axial skeleton (midline of
body)
• Amphiarthroses
• Ex: pubic
symphysis and
intervertebral
joints
Structural Classification
• Synovial Joints
• Connected by dense irregular connective tissue
• Articulating bone ends are separated by a joint
cavity containing synovial fluid
• All joints of the limbs
• All diarthroses
Features of Synovial Joints
• Articular cartilage (hyaline)
• Articular capsule (2 layers)
• Unites two bones
• Fibrous capsule: Dense Regular CT
attach to periosteum or ligament
• Synovial membrane: loose areolar
CT produces synovial fluid
• Synovial fluid: shock
absorption, nutrients, removes
microbes and debris,reduces
friction
• Joint cavity (contains synovial fluid)
• Reinforcing (Accessory) ligaments
•
•
Large joints: ACL, MCL, PCL
More support/stabilization for joints that
are under a lot of stress/pressure
Synovial Joints
• Also can contain:
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Classification
• Bursae: alleviate friction
• Tendon sheaths: wrap around tendons to reduce friction
(wrist, ankle, shoulder, fingers, toes)
• Articular discs (menisci): cartilage that helps maintain
stability, helps different shapes fit together in joint (ex:
knee, TMJ)
Damage to muscle tissue
Damage to connective tissue of joint
Inflammation
of bursae
Movements of Synovial Joints
• Chapter 6, page 197
• Movement caused by
relationship between parts
• Four categories of movements
1) Gliding
• Flat bone surfaces
against each other; no
angle
• Ex: intercarpal &
intertarsal joints
Movements of Synovial Joints
• Four categories of movements
2) Angular
• Angle change
• Includes:
• Flexion
• Extension
• Lateral flexion
• Lateral extension
• Hyperextension
• Abduction
• Adduction
• Circumduction
Movements of Synovial Joints
• Four categories of movements
3) Rotational
• Ex: head shaking no,
foot moving laterally &
medially
Movements of Synovial Joints
• Four categories of movements
4) Special Movements
• Elevation/Depression
• Protraction/retraction
• Inversion/eversion
• Dorsiflexion/plantar
flexion
• Supination/pronation
• Opposition
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Movement
Six Types of Synovial Joints
• Planar joint
• Gliding movements
• Flat surfaces
• Ex: intercarpal and
intertarsal
• Hinge joint
• Convex fits into concave
• Like door hinge
• Biaxial (no
hyperextension)
• Ex: elbow
• Pivot joint
• Rounded surface
articulates with ring
• rotational
• Ex: atlas around axis
Six Types of Synovial Joints
• Condylar joint (ellipsoid)
• Concave into convex
• Movement in multiple
directions (oval shape)
• biaxial
• Ex: wrists
• Saddle joint
• “saddle” shaped
• biaxial
• Ex: wrist and thumb
• Ball-and-socket joint
• multiaxial
• Ex: hip, shoulder
Pg. 171, fig 5.32
Synovial Joints
• Range of motion: amount of movement
• Factors affecting ROM at synovial joints:
• Structure or shape of articulating bones (how they
fit)
• Strength and tension of ligaments (depends on
position; disease, atrophy, etc.)
• Arrangement and tension of muscles (tension restricts
movement)
• Contact of soft parts (adipose tissue can affect ROM)
• Hormones (ex: relaxin with the pubic symphysis)
• Disuse (decrease synovial fluid, flexibility of ligaments
and tendons, muscular atrophy)
Homeostatic Imbalance
• Arthritis
• Inflammatory joint disorder
• Changes in joint structure occur
• Osteoarthritis, rheumatoid arthritis, gouty arthritis
• Temporomandibular joint disease
• Often caused by trauma to jaw joints, genetics, or dental procedures
• Symptoms include facial pain, headaches, grinding of teeth, popping of
jaw, and swallowing difficulties
• Not well defined in medical community
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