Joints and ligaments Flashcards
What is a joint?
Articulation of two bones as they meet / connect
What does Joint Structure determine
Determines direction and distance of movement
Range of Motion (ROM)
3 structural Classes of Joints
Fibrous
Cartilaginous
Synovial
3 Functional classes: based on degree of motion
- Synarthrosis: non-movable
- Amphiarthrosis: slightly movable
- Diarthrosis: freely movable
Characteristics of fibrous joints
United by fibrous connective tissue
•Have no joint cavity
•Move little or not at all
Types of fibrous joints
- Sutures- no movement (skull)
- Syndesmoses- little movement (DRUJ)
- Gomphosis- Fibrous peg into socket (tooth)
Properties of Fibrous Joints: Sutures
Opposing bones interdigitate. •Periosteum of one bone is continuous with the periosteum of the other.•Sutural ligament: two periostea plus dense, fibrous, connective tissue between.•In adults may ossify completely: synostosis. •Fontanels: membranous areas in the suture between bones. Allow change in shape of head during birth and rapid growth of the brain after birth.
Properties of Fibrous Joints: Syndesmoses
Bones farther apart than suture and joined by ligaments
•Some movement may occur
•Examples: radioulnar (interosseous membrane)
What is a Cartilaginous Joint
primary and secondary
2 bones united by continuous pad or cartilage
•Primary= synchrondosis
•Hyaline cartilage
•Occur at epiphyseal growth plates
- Secondary= symphysis
- Fibrocartilage
- Occur in midline of body
- Small range of controlled movement
Cartilaginous Joints properties
Joined by hyaline cartilage
•Little or no movement
•Some are temporary and are replaced by synostoses
•Some are permanent
•Some like costochondral joints develop into synovial joints
•Examples: Epiphyseal plates, sternocostal jt, sphenooccipital
Synovial Joints properties
Class of freely mobile joints
•Allow considerable movement
•Contain synovial fluid
•Movement limited by …•Muscle•Ligament •Joint capsule•Shape
•Most joints that unite bones of appendicular skeleton reflecting greater mobility of appendicular skeleton compared to axial skeleton.
explain a uniaxial Synovial Joints
Occurring around one axis, e.g. •Elbow•Ankle
explain a biaxial Synovial Joints
Occurring around two axes at right angles to each other, e.g. •MCPJ (metacarple phalangeal joint)
•RCJ (radiocarpal joint)
explain a multiaxial Synovial Joints
Occurring around several axes, e.g.
•Shoulder•Hip
Plane or gliding joints properties
Uniaxial. Some rotation possible but limited by surrounding structures, e.g.:Intervertebral, intercarpal, acromioclavicular, carpometacarpal, costovertebral, intertarsal, sacroiliac, tarsometatarsa
Saddle joints properties
Biaxial, e.g.Thumb (carpometacarpal pollicis), intercarpal, sternoclavicular
Hinge joints properties
Uniaxial. Convex cylinder in one bone; corresponding concavity in the other e.g.:Elbow, ankle, interphalangea
Pivot joints properties
Uniaxial. Rotation around a single axis.•Cylindrical bony process rotating within a circle of bone and ligament e.g.: Articulation between dens of axis and atlas (atlantoaxial), proximal radioulnar, distal radioulnar
Ball-and-socket properties
Multiaxial•Examples: shoulder and hip joints
Ellipsoid (Condyloid)
Modified ball-and-socket; articular surfaces are ellipsoid•Biaxial•Example: atlantooccipital
What is the role of Synovial cartilage (hyaline
cushions the joint absorbs shock and prevents friction and wear and tear between the bone ends.
Synovial membrane function
connective tissue which lines the inner surface of the capsule of a synovial joint and secretes synovial fluid which serves a lubricating function, allowing joint surfaces to smoothly move across each other
joint Capsule function
Encloses joint
Vital to the function of synovial joints. It seals the joint space, provides passive stability by limiting movements, provides active stability
Ligament function
Ligaments tough, fibrous connective tissue
connect bone to bone and helps to keep them stabilized within a joint space
