Transcript Articulations

Articulations
Articulations
• The main function of joints is
movement
• BUT not all joints are movable
• Besides movement, they function in
–Binding parts
–Allowing for bone growth
Fibrous
• Held together by dense connective
tissue that’s full of collagen
• Found between bones that are very
close together
Cartilaginous
• Connected by either hyaline or
fibrocartilage
• Many are temporary
–Epiphyseal plate forms a cartilaginous
joint between the epiphysis and
diaphysis oh a long bone
• Manubrium/1st rib
Synovial
• Most joints are synovial which allow for
free movement
• Consist of
–Articular cartilage
–Joint capsule
–Synovial membrane
Articular Cartilage
• Sits atop spongy bone for shock
absorption
• Resists wear
• Minimizes friction
Joint Capsule
• Outer layer is dense connective tissue
–Attaches to periosteum
–Reinforced with ligaments
• Inner layer is loose connective tissue =
synovial membrane
Synovial Membrane
• Vascular but only a few cells thick
• Secretes synovial fluid
–Lubricates cartilage surfaces
–Supplies nutrients
Types of Synovial Joints
• Ball & Socket
–Egg – shaped head articulates with a
cup shaped cavity
–Widest range of motion
–Ex: hip, shoulder
• Ball & socket
Types of Synovial Joints
• Condyloid
–Oval condyle articulates with elliptical
cavity
–No rotation
–Ex: metacarpal/tarsal to phalange
• Gliding
–Nearly flat or slightly curved
–Back & forth; twisting
–Ex: wrist, ankle
Types of Synovial Joints
• Hinge
–Convex surface fits into concave
–Moves in one plane only
–Ex: elbow, between phalanges
• Saddle
–Both articulating surfaces have both
convex and concave regions
–Moves in two planes
–Ex: between carpal & metacarpal of thumb
Types of Synovial Joints
• Pivot
–Cylinder rotates within a ring
–Rotation only
–Ex: Radius to Ulna (pronate/supinate)
–Ex: Atlas to Axis (turn head)
Sprain vs. Strain
• A sprain is the overstretching or tearing
of a ligament or joint capsule.
–Occurs when joint is forced beyond its
normal range of motion
• Strains are the stretching or tearing of a
muscle/tendon structure.
Arthritis
• Inflammation of joint
–Rheumatoid: immune system attacks
connective tissue of the joints
–Lyme: bacteria from tick causes
intermittent arthritis
Arthritis
• Osteoarthritis happens with age but
genetic early onset
• Articular cartilage softens & gradually
disintegrates
• Joint gradually deforms
Double-jointed
• You can’t actually have another set of
joints
• Double-jointed refers to hypermobility –
they stretch farther than normal
–Misaligned
–Abnormally shaped ends of bones
–Collagen defect