Articulations 1 Explain how joints are classified a Functional Classification i Based on range of motion ROM of the joint ii Three Types 1 Synarthrosis 2 Amphiarthrosis 3 Diarthrosis b Structural Classification i Relies on the anatomical organization of the joint 2 Describe the three functional classifications of joints What are the properties of these joints What are some examples of these joints a Synarthrosis i ii Extremely strong joints Immovable Joint iii Edges of bones may touch or interlock iv Fibrous or cartilaginous or fused bones v Types 1 Suture fibrous 1 Located where movement between the bones must be prevented a Bones interlocked b Bound by dense fibrous connective tissue c Found ONLY in skull d Ex 2 Gomphosis i Coronal squamous lambdoid sagittal fibrous a Fibrous connection b Ex Periodontal ligament connects teeth to jaw 3 Synchondrosis i Binds teeth to sockets cartilaginous a Rigid cartilaginous bridge between two bones b Ex 4 Synostosis i Cartilage between vertebrosternal ribs and sternum ii Epiphyseal cartilage of long bones bony fusion a Fused bones immovable b Ex i Metopic suture of skull fuses two sides of frontal bone ii Epiphyseal lines of mature long bones b Amphiarthrosis i Slightly movable joint 1 More movable than synarthrosis 2 Stronger than freely movable ii Articulating bones are connected by collagen fibers or cartilage iii Types 1 Syndesmosis fibrous a Bones are connected by a ligament b Ex Articulation between tibia and fibula 2 Symphysis Cartilaginous a Bones are separated by a pad of fibrocartilage b Ex Pubic symphysis c Diarthrosis i Freely movable joint ii Synovial Joints iii Permit a wide range of motion iv Within articular capsules v Lined with synovial membrane vi Ex 1 Ends of long bones upper and lower limbs 3 Describe the four structural classifications of joints What are the properties of these joints What are some examples of these joints a Bony b Fibrous i Synotoses synarthroses i Sutures and gomphoses synarthroses ii Syndesmosomes amphiarthroses c Cartilaginous d Synovial i Only diarthroses i Synchondroses synarthroses and symphyses amphiarthroses 4 Describe the structure of a synovial joint a Surrounded by a two layered articular capsule i Exists within these articular capsules b Lined with synovial membrane i Doesn t cover the articulating surface within the joint c Joint Cavity containing synovial fluid 5 Describe the structures found in a synovial joint a Articular Cartilage i Pad articulating surfaces within articular capsules 1 Prevent bones from touching b Synovial Fluid i Contains slippery proteoglycans glycoproteins secreted by fibroblasts ii Consistency of heavy molasses iii Reduces friction iv Functions 1 Lubrication a Articular cartilages act like sponges filled with synovial fluid compression of it pushes some synovial fluid out b When compression stops fluid is pulled back into the articular cartilages 2 Nutrient Distribution chondrocytes 3 Shock Absorption a Fluid circulates as joint moves provides nutrients to a Cushions joints that are subjected to compression from shocks b Shock is lessened as fluid spreads across articular surfaces and out to the articular capsule c Accessory Structures i Cartilages Fat Pads Ligaments Tendons and Bursae 6 What are the accessory structures found at the synovial joint What are their functions a Cartilages i Cushions the joint 1 Fibrocartilage pad called a meniscus or articular disc 2 Can subdivide the synovial cavity channel the flow of fluid or allow variations in shape of the articular surfaces b Fat Pads i Adipose tissue superficial to the joint capsule 1 Localized masses of adipose tissue covered by a layer of synovial membrane ii Protect articular cartilages c Ligaments shape 1 When bones move fill in spaces created as the joint cavity changes i Support strengthen and reinforce joints ii No direct blood supply heals slower than bone iii Sprain d Tendons stretched ligaments with torn collagen fibers i Attach to muscles around joint ii Help support joint iii Limit the joint s range of motion and provide mechanical support for it e Bursae i Singular bursa a pouch ii Pockets of synovial fluid iii Cushions areas where tendons or ligaments rub formed here too iv Bursitis inflamed bursae causing pain can result from repetitive motion 1 Reduce friction 2 Act as shock absorbers irritation trauma infection 7 Describe how the range of motion is reduced at a synovial joint Why is this important What happens if this does not occur a The greater the range of motion at a joint the weaker it becomes b Four Factors that Limit Range of Motion i Collagen fibers joint capsule ligaments ii Shape of the articulating surfaces and menisci iii Presence of other bones muscles or fat pads iv Tension in the tendons of articulating bones c Why is it important i Prevent injury 1 Stabilize joint ii Pain receptors are NOT found on the inside of synovial joints Pain felt due to joint damage results from nerves that monitor capsule ligaments and tendons d Injuries of Synovial Joints what happens if ROM is not reduced i Dislocation luxation 1 Caused by extreme stress 2 Articulating surfaces forced out of position 3 Damages articular cartilage ligaments joint capsule 4 Shoulder Joint most prone to this injury ii Subluxation 1 A partial dislocation less severe iii Double Jointed weakly stabilized joints prone to dislocation or Subluxation 8 Describe the different types of joint movements a A joint cannot be both mobile AND strong i The greater the mobility the weaker the joint ii Mobile joints are supported by muscles and ligaments not bone to bone connections b Linear Movement Gliding i Two surfaces slide past each other ii Movement can occur in almost any direction but is slight 1 Rotation is prevented by the capsule and ligaments iii Nonaxial small sliding movements OR Multiaxial any direction iv Example 1 Between carpal or tarsal bones and motion between the clavicle and sternum c Angular Movement i Flexion 1 Angular motion in the anterior posterior plane 2 REDUCES angle between elements 3 Ex Flex head toward chest intervertebral joints ii Extension INCREASES angle between elements 1 Angular motion in the anterior posterior plane 2 3 In anatomical position all joints except ankle are at full extension 4 Ex Extend head back to anatomical position iii Hyperextension 1 Angular motion of extension past the anatomical position a Prevented by ligaments bony processes and soft tissues 2 Ex Hyperextension of neck to
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