B.1.2 Joints (2)

What are joints

when two or more bones articulate

What do joints increase?

mobility

What are the different types of joints?

fibrous, cartilaginous and synovial

Do fibrous joints have a cavity?

no cavity

What do fibrous tissues connect?

bones (the edges)

What is fibrous joints continuous with?

periosteum

What is not allowed at fibrous joints?

movement

Do cartilaginous joints have a cavity?

no cavity

What are cartilaginous joints connected by?

cartilage

What are cartilaginous joints separated by?

fibrocartilage disk or a thick layer of hyaline cartilage

What is limited at a cartilaginous joint?

movement

Do synovial joints have a cavity?

cavity present

What are articulating surfaces enclosed within a synovial joint?

fluid-filled joint capsule

What are synovial joints?

the most commonly occuring type of joints

What are synovial joints important for?

mobility

What are the different types of synovial joints?

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

Ball and Socket description

rounded end of one bone fits inside a cup shaped ending on another bone

Example of a ball and socket joint

shoulders and hips

Movement of a ball and socket joint

rotation

Pivot description

has a ringbone that fits over a bone protrusion

Example of a pivot joint

neck

Movement of a pivot joint

rotation

Hinge description

only allows forwards and backwards movement

Example of a hinge joint

elbow and knee

Movement of a hinge joint

extension and flexion

Condyloid description

oval shaped bone end which fits into a corresponding shaped bone end

Example of a condyloid joint

wrist

Movement of a condyloid joint

flexion, extension, circumduction

Gliding description

two flat faces of bone that slide over one another

What do gliding joints allow for?

little movement in all direction

Example of a gliding joint

tarsals in the ankle

Movement of a gliding joint

very little movement

Saddle description

found between convex and concave articulating bones

Examples of saddle joints

thumb, thorax, ear, heal

Movement of saddle joints

extension, flexion, abduction, adduction

What are the features of a synovial joint

articular cartilage, articular capsule, synovial membrane, synovial fluid, menisci, bursae

What does the articular cartilage do?

covers the articulating surfaces of the bones

What does the articular cartilage reduce, absorb and protect?

friction, shock, the bones

What does the articular cartilage vary in?

thickness

What can happen to the articular cartilage?

can wear away

What does the articular capsule surround?

the joints

What does the articular capsule allow for?

joint movement due to its flexibility

What does the synovial membrane do?

secretes synovial fluid

What does the synovial fluid do?

lubricates the joint cavity, reduces friction, provides nutrients to the cartilage (diffusion)

Where is the menisci found?

between bones

What does the menisci act as?

a cushion

What do menisci allow the bones to do?

fit together more tightly

What do menisci provide?

stability to the joint

What are the bursae?

small fluid filled sacs where two structures rub against each other

What do bursae provide?

lubrication and reduces friction

What are bursae lined by?

a synovial membrane

Where are bursae located?

in areas of high stress