HAP Ch 8A

3 structural classifications of joints

fibrous, cartilaginous, synovial

3 functional classifications of joints

synarthroses, amphiarthroses, diarthroses

Three types of fibrous joints

sutures, syndesmoses, gomphoses

sutures

rigid, interlocking joints containing short connective tissue fibers; allow for growth during youth and then closes off in adulthood

synostoses

closed sutures

Syndesmoses

A joint in which the bones are united by a ligament or a sheet of fibrous tissue.

Gomphoses

peg-in-socket fibrous joint

two types of cartilaginous joints

synchondroses, symphysis

Cartilaginous Joints

allow only slight movement and consist of bones connected entirely by cartilage

Synchondroses

A bar or plate of hyaline cartilage unites the bones

Almost all are synarthrotic

Symphyses

A joint in which the bones are connected by fibrocartilage; strong, amphiarthrotic (slightly movable) joints

Synovial Joints

Bones separated by fluid-filled joint cavity

All are diarthrotic

Include ~ all limb joints; most joints of body

Joint (synovial) cavity

small, fluid-filled potential space that is unique to synovial joints

Articular cartilage

consists of hyaline cartilage covering ends of bones; prevents crushing of bone ends

Synovial fluid

joint-lubricating fluid secreted by the synovial membrane

Articular discs (menisci)

Fibrocartilage separates articular surfaces to improve "fit" of bone ends, stabilize joint, and reduce wear and tear

Fatty pads

cushioning between fibrous layer and synovial membrane or bone

Bursae

flattened fibrous sacs lined with synovial membrane and containing a thin film of synovial fluid; reduce friction where ligaments, muscles, skin, tendons, or bones rub together

Tendon sheaths

elongated bursae wrapped completely around tendons subjected to friction

types of synovial joints

plane, hinge, pivot, condylar (condyloid), saddle, ball and socket

plane joint

short slipping or gliding movements; i.e. carpals

hinge joint

Joint between bones (as at the elbow or knee) that permits motion in only one plane

pivot joint

rotating bone turns around an axis; i.e. connection between radius/ulna and humerus

condyloid joint

synovial joint that does everything except rotating

saddle joint

type of joint found at the base of each thumb; allows grasping and rotation

ball and socket joint

a type of joint that allows for movements in many direction around a central point (for example, shoulder and hip)