module 9 joints Flashcards
joint classifications: movement
synarthrosis: immoveable
amphiarthosis: slightly moveable
diarthrosis: freely moveable
joint classifications: structure
fibrous
cartilaginous
synovial
fibrous joints
usually synarthroses: immovable sutures in skull syndesmoses:2 bony components joined by ligament or interosseous membrane - fibula and tibia - radius and ulna gomphoses: peg implanted in hole; teeth
Cartilaginous joints
symphysis: wt bearing structures, important in transmitting stress and providing stability. Only slight movement
- bones united by a pad or disk of fibrocartilage
- - symphysis pubis, intervertebral disks
synchondrosis: allows bone growth while providing stability
- found at growth sites
- bones united by hyaline cartilage
- - joints between ribs and sternum
synovial joints
most movable, most complex
- enclosed by fibrous joint capsule
- interior lined with thin synovial lining
- movement due to contraction of muscle-tendon unit
- stability increased by soft tissue structures
- synovial fluid: lubrication, coats joint surfaces
- articular cartilage covering opposing joint surfaces
synovial joint capsule
has 2 layers of connective tissue
- outer: fibrous membrane composed of collagenous tissue
- dense, encapsulated whole joint
- attached to periosteum
- inner: synovial membrane, contains hyaluronic acid and lubricin
hyaluronic acid
inner layer of synovial membrane
viscosity and decreased friction between joint surfaces
- helps maintain synovial fluid volume by slowing diffusion of water out of space
lubricin
inner layer of synovial membrane
lubricates cartilage and articular surfaces
synovial joints 3 catergories, ROM
uniaxial
biaxial
triaxial
uniaxial synovial joint
allows motion around a single axis
- hinge/ginglymus: flexion and extension: finger, elbow, knee
- pivot/trochoid: rotation as movement: union between 1st and 2nd vertebrae, superior radioulnar joint of elbow
biaxial synovial joint
2 axes of movement and permits movement in 2 planes
- condyloid: metacarpophalangeal joint of hand
- flexion and extension
- adduction and abduction
- saddle/sellar: surface convex in one plane and concave in other: carpometacarpal joint of thumb
triaxial synovial joint
movement around 3 axes, motion in 3 planes, permits gliding between 2 bones: carpal joints of hand
- ball and socket: hip, shoulder
- flexion and extension
- adduction and abduction
- rotational
articular cartilage
appears smooth, shiny, and white
- designed to withstand stress imposed by movement
- distributes joint loads over large area
- decreased stress of prolonged compression
- movement of joint with minimal friction and deterioration
- devoid of vessels, lymph channels, and nerves
articular cartilage composistion
hydrophillic
main cell: chondrocytes
- manufacture the organic components of extracellular matrix: collagen fibers, elastin, fibrillin
- surrounding extracellular matrix: proteoglycan component
proteoglycan
provides cartilage with some stiffness
allows potential to be compressed by absorbing or extruding water with pressure
