Skeletal system - Joints Flashcards
What are joints (articulations)?
Sites where two or more bones meet
What are the 2 functions of joints?
- Provide for skeletal mobility
- Hold the skeleton together
Weakest/strongest parts of the skeleton?
Weakest
What is the functional classification of joints based on?
Focuses on the amount of movement
Name the different functional classifications
- Synarthroses
- Amphiarthroses
- Diarthroses
What is the structural classification based on?
Material binding them & presence/absence of joint cavity
Name the structural classifications
- Fibrous
- Cartilagenous
- Synovial
Name the fibrous joints
Suture, syndesmoses & gomphoses
Name the cartilagenous joints
Synchondroses, symphyses
Name the synovial joints
Gliding, hinge, pivot, condyloid, saddle, ball & socket
What are sutures?
Dense fibrous connective tissue
Describe syndesmoses
Band/cord of connective tissue
What is gomphosis?
Peg-in-socket arrangement surrounded by fibrous tissue
Where do sutures occur?
Between bones of skull
What bind bones of the skull together tightly?
Rigid splices
Syndesmoses are connected by bones/ligaments/joints & bands of fibrous/connective tissue
ligaments, bands of fibrous tissue
Give an example of gomphoses
Tooth with its bony alveolar socket
- Ligament = periodontal
What are cartilagenous joints?
Articulating bones united by cartilage
What does hyaline cartilage do in synchondroses?
Unites the bones
Are synchondroses movable/immovable?
immovable
Give an example of synchondroses
Epiphyseal plates
Are symphyses movable/immovable?
slightly movable
Give examples of symphyses
Intervertebral discs
Are synovial joints movable/immovable?
Freely movable
Name the parts of a synovial joint
- Articular cartilage
- Joint (synovial) cavity
- Articular capsule
- Synovial fluid
- Reinforcing ligaments
- Nerves
- Blood vessels
What does articular cartilage do?
- Spongy cushion absorbs compression
- Protects ends of bones from being crushed
How many layers in the articular capsule?
Two - outer & inner
What is the difference between outer & inner?
Outer - Fibrous capsule of dense irregular connective tissue
Inner - Synovial membrane of loose connective tissue
What does synovial fluid do?
Nourishes cartilage & functions as a slippery lubricant
What does synovial fluid contain?
Special glycoproteins
Name the 3 types of reinforcing ligaments
Capsular - part of fibrous capsule
Extracapsular - outside capsule
Intracapsular - deep to capsule
What do nerves do?
- Detect pain
- Monitor stretch
What do blood vessels do?
- Rich blood supply
- Extensive capillary beds produce blood filtrate
What joint allows 2 kinds of movement?
Jaw
What is a TMJ (temporomandibular joint)?
Knee
What do bursae and tendon sheaths act as?
Ball bearings
What are bursa?
Ligaments, muscles & bones overlie each other and rub together
Where can a tendon sheath be found?
Only on tendons subject to friction
What factors influence joint stability?
- Articular surfaces
- Ligaments
- Muscle tone
What movements do synovial joints do?
- Gliding
- Angular movements
- Rotation
- Special movements
What is gliding?
Flat bone surface glides over another similar surface, e.g. intercarpal joints
What are angular movements?
Movements that occur along the sagittal plane
What is flexion?
Decreases the angle of the joint
What is extension?
Increases the angle of the joint
What is hyperextension?
Excessive extension beyond normal range of motion
What is abduction?
Movement away from midline
What is adduction?
Movement toward the midline
What is circumduction?
Flexion, abduction, extension & adduction of a limb
What is rotation?
Turning of a bone around its own longitudinal axis e.g. humerus & femur
What is supination?
Turning hand backward
What is pronation?
Turning hand forward
What is dorsiflexion?
Upward movement
What is plantar flexion?
Downward movement
What is inversion?
Turn sole medially
What is eversion?
Turn sole laterally
What is protraction?
Anterior movement
What is retraction?
Posterior movement
What is elevation?
Lifting body part superiorly
What is depression?
Moving body part inferiorly
What is opposition of the thumb?
Movement in saddle joint so thumb touches tips of other fingers
What is a plane joint?
Allow only short gliding movements, no rotation e.g. intercarpals
What are hinge joints?
A cyclindrical shaped projection of bone fits into a trough shaped surface of another bone e.g elbow
What are pivot joints?
Rounded end of a bone into a ring of bone and ligaments on another e.g. radius & ulna
What are condyloid joints?
Oval articular surface of one bone fits into a complementary concavity of another e.g. MCP joints (fingers)
What are saddle joints?
Condyloid joints but greater freedom of movement e.g. thumbs
What are ball & socket joints?
Spherical head of one bone articulates with cuplike socket of another, most freely moving joints e.g. shoulder
The more moveable a joint, the more/less stable it is.
less
