AP Exam 3 Joints

Articular (hyaline) cartilage

covers articular surfaces of bones in cartilaginous and synovial joints

hyoid bone

the only bone in the body that does not articulate with another joint

two ways to classify joints

based on structure(kinds of tissue found)

based on function (types of movement allowed)

synarthrotic

immovable

diarthrotic

movable

structure joints

fibrous (generally synarthrotic),cartilaginous, synovial (generally diarthrotic)

function joints

synarthroses- immovable (axial skeleton)

amphiarthroses - slightly movable (axial skeleton)

diarthroses- freely movable

fibrous joints

bones are joined by fibrous tissue

3 subtypes:

sutures

syndesmoses

gomphoses

suture

joint held together with very short, interconnecting fibers, and bone edges interlock

synostosis- closes suture, from fibrous tissue ossification

dense regular connective tissue fibers continuous with periosteum

also facial sutures

syndesmosis

Joint held together by a ligament. Fibrous tissue can vary in length, but is longer than in sutures

are amphiarthrotic

ligaments connect bones to bones, tendons connect muscle to bones

gomphosis

“Peg in socket” fibrous joint. Periodontal ligament holds tooth in socket

only example is teeth

cartilaginous joints

bones are joined together by cartilage, 2 types

synchondosis - hyaline cartilage

symphyses - fibrocartilage

hyaline cartilage

found in synchondroses, covers the ends of long bones in joint cavities; forms costal cartilages of ribs

synchondroses (synchondrosis)

bones united by hyaline cartilage, these joints at ribs are generally synarthrotic (immovable)

epiphyseal plate, costochondral joint, first sternocostal joint

symphyses (symphysis)

bones united by fibrocartilage

intervertebral joit, pubic symphysis

*there is still hyaline cartilage at bone surfaces, fibrocartilage is in-between

fibrocartilage

found in symphyses, located at intervertebral discs, pubic symphysis, discs of knee joint

spinal curvatures

concave and convex sections

1° - thoracic, saccral,

2° - cervical, lumbar

newborn spine

only have 1° spine, cervical develops when infant starts to raise head, lumbar develops when infant starts to walk

abnormal curvatures

problematic because of constricting ribcage and its expansion

herniated disc (slipped, prolapsed)

annulus (outer ring) ruptures, nucleus (inner) protrudes through

synovial joints

diarthrotic (freely movable joints) different structure than fibrous and cartiligous joints but have similar components - shoulder, knee

The fibrous layer of the articular capsule is continuous with periosteum

ligaments also pressent

articular capsule of fibrous layer in synovial joints

has a fibrous outer layer, and inner layer with synovial membrane that has synoviocytes (make synovial fluid)

also is innervated and supplied with blood vessels

reinforcing ligaments

in synovial joints, capsular ligaments: continuous with fibrous layer

of articular capsule, extra- or intracapsular ligaments: one type is deep to the capsule, one is outside.

bursa/bursae

fluid filled sacs in synovial joints

rheumatoid arthrities

multifactorial (genetic, enviornmental, etc) autoimmune disease, has articular (at the joint), extra-articular (outside or around the joint), and systematic (body wide) effects

rheumatoid arthritic process

synovitis: inflammation of synovial membrane. (infiltration of immune cells and angiogenesis)

synovial membrane becomes hyperplastic, expands

osteoclast rich region of the synovial membrane destroys bone

enzymes destroy cartilage

results of rheumatoid arthritis at joints

scar tisse formation, scar tissue ossification, loss of joint mobility

possible systematic effects of rheumatoid arthritis

anemia (blood isn’t carrying enough oxygen to adequately supply tissues)

cardiovascular disease

osteoporosis

fatigue

depression

osteoarthritis

Previous understanding: “wear and tear”, age-related

More modern understanding: there are biochemical and cell changes at the

synovial joint tissues. Lead to articular cartilage breakdown.

gouty arthritis (gout)

Uric acid (normal waste product) rises in blood

‘Crystals form in soft tissues of joints