100 likes | 355 Views
DIFFERENT KINDS OF JOINTS. 5.4. Joints are where two or more bones meet . They are divided into three types depending on how freely the bones can move . Movement would not be possible without the three joint types . 1. Fixed or immovable joints Eg . Joints between cranium plates .
E N D
Joints arewheretwoormorebonesmeet. Theyaredividedintothreetypesdepending on howfreelythebonescanmove. Movement would not bepossiblewithoutthethreejointtypes. 1. Fixed orimmovablejoints Eg. Joints betweencraniumplates. 2. Slightlymoveablejoints Eg. Betweenvertebraeandribs 3. Freelymoveable (synovial) joints Eg. Knee, shoulderandelbowjoints
Fixed orimmovablejoints • Bones cannotmove at all. • They interlock/overlap-held togetherbytoughfibre. • Present in areasrequiringgreatstrength. The joints in thecraniumandsacrum (baseofthespine) aregoodexamples. Sacrum
Slightlymoveablejoints • Limited movement. • Held togetherby strong, whitestrapscalledligamentsandjoinedbycartilage. This actsas a cushionandstopsbonesrubbingtogether. • Eg. Joints betweenyourvertebraeandribs. In thevertebraethecartilageactsasshockabsorberswhenrunningandjumping. • The jointsbetweenyourribsandsternummoveslightlywhenyoubreath in and out. Remember- Ligaments:Joinbonetobone Tendons:Joinmuscletobone
Freelymoveablejoints Also calledsynovialjoints. They all havetheseparts: Joint capsule: Holds togetherandprotects Synovialmembrane: Lines thecapsuleandcontainssynovial fluid Joint cavity: Small gapbetweenthebones Cartilage: Covers end ofbones Ligaments: Holds bonestogetherandkeepsthem in place Eg.
Freelymoveablejoints (cont) Dividedintofourtypes: 1) Ball/socket, 2) Hinge, 3) Pivot 4) Gliding Ball and Socket Joint • Most moveablejoint • Onebonehas a ball that fitsinto a socket on the otherone. • Can turn in manydirections. • Eg. Hip andshoulderjoint. Hip jointShoulderjoint
The hinge joint • Works like a hinge on a door. • The bonecan swing backwardsandforwards. • Cotton reelshapedbonefitsinto a hollow on theother. • The joint will open untilitisstraight, but nofurther. • Eg. The elbowandkneejoints
The pivotjoint Onebonehas a bitthatjuts out, like a peg. This fitsinto a ring ornotch on theotherbone. • Limited movement (Onlyrotation). • Eg. Joint betweenatlasandaxis- The top twobonesofyourvertebrae. • The jointbetweentheradiusandtheulna (Bones in yourlowerelbow)
The glidingjoint • The endsoftheboneare flat enoughtoglideovereachother. • Thereis a littlemovement in all directions. • Least movementof all synovialjoints. • Eg. Joints betweencarpals (hand) andtarsals (foot). carpals