Secondary TwoTopic: Bones and JointsSub Topic: Joints and

Movements

Content Purpose• Students will be able to:• understand what is a joint;• name the 3 types of joints;• name the 2 main causes of joint

injuries.

Language Purpose• Fixed / Immoveable joints

• Slightly moveable joints• Freely moveable joints• Ligaments• Joint cavity• Synovial membrane

Social Purpose• One conversation• No sleeping• Putting of palm on whiteboard• Class too noisy and need to

quieten down

WHAT IS JOINTS?

Do you remember…How many bones do we have in our

body?◦ 206 bones

Between connecting bones…The bones connected together by

ligaments (strong fibres)The area where two or more

bones meet is called a joint

Ligament

Joint

Types of JointsThere are 3 types of joints

◦Fixed / Immoveable joints◦Slightly moveable joints◦Freely moveable joints

FIXED / IMMOVEABLE JOINTS

Types of joints

Fixed or Immoveable JointsAlso known as fibrous jointsJoints with very tough fibre to prevent

movement between the connecting bones

Can you think of any immoveable joints?

Fixed joints

Fixed or Immoveable JointsWhy would we want immoveable

joints?◦Eg. Skull (cranium)◦Babies are borned with the plates in

the cranium not joined together◦Facilitates birth / delivery◦The plates are joined after birth to

provide protection for the brain

SLIGHTLY MOVEABLE JOINTS

Types of joints

Slightly Moveable JointsAlso known as cartilaginous jointsAllow very small amount of

movementJoints are connected by cartilageCan you name some slightly

moveable joints?

Slightly Moveable Joints

Cartilage pad

Joint between each

vertebrae

Joint between ribs and sternum

Slightly Moveable JointsThe connecting cartilage acts as

a cushioning layer (shock absorber) between the bones

The bones serves largely as protective layer for important parts of the body

But allows slight movement to facilitate day-to-day actions◦Eg. Bending of back, breathing

FREELY MOVEABLE JOINTS

Types of joints

Freely Moveable JointsMore commonly known as

synovial jointsAllow a large degree of

movementExist 4 different types which

allow different kind of movement◦Ball and socket◦Hinge◦Pivot◦Gliding

Covering in next lesson

Freely Moveable JointsA typical freely moveable joint

looks like this:

Freely Moveable JointsParts of the typical moveable

joint include:

Freely Moveable JointsThe functions of the various parts of a

freely moveable joint are as follow:

Freely Moveable JointsCan you name 5 examples?

Trivia…

◦ Bones pulled further apart◦ Expansion of the synovial

membrane◦ Results in temporary

expansion of synovial cavity

◦ Increase volume = decrease pressure

◦ Cavitation (formation of air bubbles)

◦ When pressure over-reduced, the bubbles burst, thus the “CRACK” sound

◦ Not medically proven to be harmful till date

What happens when you crack your knuckles (joints at the finger)?

JOINT INJURIES

Joint InjuriesJoint injuries come in few forms:

◦Bone injuries Wear and tear Impact

◦Ligament injuriesMost common joint injuries

happened on◦Knee◦Ankle Why?

Our KneeThree bone meet at the knee

joint◦Femur (thigh bone)◦Tibia (shin bone)◦Patella (knee cap)

Our KneeOther components of knee joint

◦ Articular cartilage – Protects end part of femur and tibia.

◦ Meniscus – Additional cartilage material between femur and tibia for shock absorption

◦ Ligaments – Strong fibres holding femur and tibia together

Knee InjuriesArticular cartilage wear and tear

at the knee

Knee InjuriesMeniscus tear – Happens when

there’s sudden movement of twisting, pivoting, or being tackled

Knee InjuriesWear and tear of cartilage due to

heavy weight

Other Joint InjuriesMore joint and bone related

injuries will be covered in the later part of the term

Lets Recap• Fixed / Immoveable joints• Slightly moveable joints• Freely moveable joints• Ligaments• Joint cavity• Synovial membrane