Joints Flashcards
Articulation
Site where two bones meet.
Joint functions
Holds skeleton together & gives skeleton mobility.
Structural classification of joints
Fibrous
Cartiloginous
Synovial
Functional classification of joints
Synarthrosis
Amphiarthrosis
Diarthrosis
3 types of fibrous joints
Sutures
Syndesmoses
Gomphoses
(Fibrous) Sutures
Found only in the skull. Short interconnecting fibers.
(Fibrous) Syndesmoses
Invisible joints. Bones connected by ligaments. Range from immovable to slightly moveable.
Examples: Synarthrotic distal tibioibular joint
Diarthrotics connection between radius and ulna
(Fibrous) Gomphoses
Teeth sockets. Periodontal ligaments.
Synovial joints
All are diarthrotic. All limb joints (most of body)
5 distinguished features:
- Articular/Hyaline cartilage
- Synovial fluid
- Joint (Synovial) cavity; small space
- Joint capsule (articular capsule)
- Rich nerve & blood supply
Friction-reducing structures
Bursae & tendon sheath
Bursae
Flattened fibrous sacs lined with synovial membrane. Synovial fluid.
“Ball bearings.”
Tendon Sheath
Elongated sacs contain synovial fluid and wraps completely around tendon.
Synovial Joint Movements
- Gliding
- Angular
- Rotation
- Special movements
Gliding
Flat bone surface glides/slips another similar surface. Intercarpals/carpals: wrists
Angular
Flexion Extension Hypertension Abduction Adduction Circumduction
Flexion
Decreases the angle of joint.
Extension
Increases angle of joints.
Hypertension
Excessive extension of normal range of motion
Abduction
Away from the midline.
Adduction
Toward midline.
Circumduction
Flexion+Adduction+Abduction+Extension
Rotation
Turning of a bone
Special movements
Supination Pronation Dorsiflexion Plantarflexion Inversion Eversion Protraction Retraction Elevation Depression Opposition
Supination
Palms facing anteriorly. Radius and ulna are parallel.
Pronation
Palms facing posteriorly. Radius rotates over ulna.
Dorsiflexion
Toes pointing towards shin
Plantarflexion
Pointing toes down
Inversion
Sole of foot faces medially.
Eversion
Sole of foot faces laterally.
Protraction
Mandible juts out.
Retraction
Mandible is pulled toward neck.
Elevation
Lifting body part superiorly; shrugging shoulders.
Depression
Lowering body part; gasp
Opposition
thumb
Classification of Synovial Joints
Plane Hinge Pivot Condyloid Saddle Ball & socket
Plane
Flat articular surfaces gliding movements; wrists.
Hinge
Motion along a single plane. Flexion & Extension.
mandible cylindrical into trough shape
Pivot
Round end of one bone fits into sleeve/ring of another one.
- radius*
- atlas rotates on pivot point*
Condyloid
Permits all angular movements.
Oval articular surface of bone fits into oval shaped depression of another
Saddle
Allow greater freedom of movement. Concave & convex areas.
Ball and socket
Rounded head of one bone fits into cuplike depression of another.
Common Joint Injuries
Sprains, Cartilage tears, dislocations.
Sprain
Ligaments are stretched or torn. Partial tears slowly repair themselves. Complete ruptures; surgical repairs.
Cartilage tears
Rarely repair themselves. Fragments may cause joint to lock or bind.
Dislocations
Bones forced out of alignment.
Sprains, inflammation, joint immobilization.
Arthritis
Over 100 different types of inflammatory/degenerative
Most widespread crippling disease
Pain stiffness, swelling
Osteoarthritis
Overuse of joints. Common, irreversible, degenerative. Normal aging process. More cartilage destroyed than replaced.
Rheumatoid Arthritis
Inflammatory, autoimmune. Cells migrate to joints. Synovial membrane thickens, erodes cartilage, scar tissue forms, articulating bone ends connect.
