hbs 1.2.5 joints

adduction

moves toward midline

abudction

moves away from midline

circumduction

moving in a circle about a fixed point

rotation

turning or pivoting of a bone about its axis

extension

increases angle of a joint

flexion

decreases angle of joint

plantar flexion

foot moves downward and towards ground

dorsiflexion

foot moves upward or backward

6 types of synovial joints

pivot, hinge, saddle, plane, condyloid, ball and socket

pivot joint

• one bone articulates within a ring

• made of ligament

• secures to another bone

• rotation about a single axis

hinge joint

• between round and trough shape of 2 bones

• enables flexion and extension

saddle joint

• between 2 bones

• each bone has concave articular surfaces in one direction and convex in the other

• allows for flexion or extension and abudction or adduction

plane joint

• allow bones to glide against each other

• between flat surfaces of 2+ bones

• surrounded by strong ligaments that limit range of motion

condyloid joint

• between rounded oval surface of one bone and shallow depression of another bone

• enables flexion, extension, abudction, adduction, and slight circumdiction

• only limited by articular shape and surrounding ligaments

ball and socket joint

• ball-shaped head of one bone articulates w/ cup-like socket of another

• enables abduction, adduction, flexion, extension, internal and external rotation, and circumdiction

• widest range of motion

synovial fluid function

reduces friction between the cartilages of synovial joints during movement