4Different types of joint There are 3 different types of joint:1. Immovable (or fixed) joints2. Slightly movable jointsReference to skeletal structures could be enhanced by using a skeleton or skeletal models if available. Use this presentation to remind students of the names of a range of bones. Students must be confident in naming the bones of the skeleton and their position/ location in the body. Without this understanding they will struggle to identify the bones that form joints.3. Movable (or synovial) joints
51. Fixed or immovable joints There are fewer than 10 immovable joints in the body.They are sometimes called fibrous joints because the bones are held together by tough fibres.Immovable joints can be found in the skull and pelvis, where several bones have fused together to form a rigid structure.Fixed or immoveable joints such as those of the flat bones of the skull allow very slight movement – ask students why they should allow a little movement. Movement is necessary for expansion of the soft tissues of the brain and to absorb some of the force of impacts – if joints were completely fixed they might crack with an impact such as a blow on the head.
62. Slightly movable joints Slightly movable joints are sometimes called cartilaginous joints.The bones are separated by a cushion of cartilage. The joints between the vertebrae in the spine are cartilaginous joints.The bones can move a little bit, but ligaments stop them moving too far. This is why we can bend, straighten and rotate through the back, but not too far.bonecartilageboneDiscuss with students the structure of the spinal column and why slightly moveable joints are the most suitable type of joint for the cervical, thoracic and lumbar spine areas. Ask them why the sacrum and coccyx areas of the spine are fixed joints? Answer: for attachment of lower back muscles (Sacrum) and balance (coccyx).ligaments
73. Freely movable or synovial joints 90% of the joints in the body are synovial joints. They are freely movable.Synovial joints contain synovial fluid which is retained inside a pocket called the synovial membrane. This lubricates or ‘oils’ the joint.All the moving parts are held together by ligaments.These are highly mobile joints, like the shoulder and knee.Synovial fluidSynovial joints offer a wide range of sporting movement.Synovial membraneKnee
9Connective tissuesConnective tissues are vital to the functioning of joints. There are 3 types of connective tissue:Ligaments are tough, elastic fibres that link bones to bones.Tendons connect muscles to bones.Discussion of the properties of the different connective tissues would be relevant here.Ligaments – are elastic allowing the bones to twist and turn – however if the stress on the ligaments is too great or forceful they can be overstretched or torn (like an elastic band) and will cause injury to the sportsperson. The cruciate ligaments of the knee are commonly injured in sport.Cartilage – is found at the ends of bones and is smooth and slightly flexible providing shock absorption and reducing friction for ease of movement between bones/ jointsTendons – are less elastic and join bone to muscle – like ligaments they can be damaged by the stress and strain of excessive movements – the achilles tendon that joins the foot to the calf muscle (gastrocnemius) can be injured through repeated jumping movements.Cartilage prevents the ends of bones rubbing together at joints. Its slippery surface also helps to lubricate the joint.
10Ligaments and tendons are strengthened by training. Tendons and ligamentsLigaments are responsible for holding joints together. They prevent bones moving out of position during the stresses of physical activity.If they are pulled or twisted too far by extreme physical movements, ligaments can tear and the joint may dislocate.Tendons anchor muscles to bones, allowing the muscles to move the skeleton. Tendons are not very elastic – if they were, then the force produced by muscles would be absorbed instead of creating movement.Tendons can also be torn if subjected to too much force.Ligaments and tendons are strengthened by training.
12Freely movable (synovial) joints The joint capsule is an outer sleeve that protects and holds the knee together.The synovial membrane lines the capsule and secretes synovial fluid – a liquid which lubricates the joint, allowing it to move freely.Synovial fluidFemurSynovial membraneCartilageTibiaJoint capsuleSmooth coverings of cartilage at the ends of the bones stops them rubbing together and provide some shock absorption.Students should be able to recognise the key structures of the knee and their function.Ligaments hold the bones together and keep them in place.
13Types of synovial joints In ball and socket joints, the rounded end of one bone fits inside a cup-shaped ending on another bone.HipBall and socket joints allow movement in all directions and also rotation. The most mobile joints in the body are ball and socket joints.Examples: Shoulders and hips.Describe ball and socket joints at the hip and shoulder. Discuss the movements possible at these joints. How do they help during sport?
14Types of synovial joints Pivot joints have a ring of bone that fits over a bone protrusion, around which it can rotate.These joints only allow rotation.AtlasExamples: The joint between the atlas and axis in the neck which allows you to shake your head.Axis
15Types of synovial joints In saddle joints, the ends of the two bones fit together in a special way, allowing movement forwards and backwards and left to right, but not rotation.Examples: The thumb is the only one.Hinge joints – as their name suggests – only allow forwards and backwards movement.Examples: The knee and elbow.Elbow
16Types of synovial joints Condyloid joints have an oval-shaped bone end which fits into a correspondingly shaped bone end.They allow forwards, backwards, left and right movement, but not rotation.Examples: between the metacarpals and phalanges in the hand.Gliding joints have two flat faces of bone that slide over one another.They allow a tiny bit of movement in all directions.Examples: between the tarsals in the ankle.
21Tasks Working with a partner: Take it in turns to demonstrate a simple sporting movement, for example performing a biceps curl or taking a step forward.Together, analyse the movement and decide what types of movement are occurring at each joint.Now take it in turns to name a joint. Ask your partner to demonstrate and name all of the movements possible at that joint.For example, the hinge joint at the elbow shows flexion, extension and slight rotation.
22The structure of the knee joint (hinge) The knee is a very large and complex joint. You need to know the details of how it works.The femur is hinged on the tibia so that the leg can be bent (flexion) and straightened (extension).Cruciate ligaments bind the bones together by crossing inside the joint.Other ligaments act to stabilise the joint.The patella increases the leverage of the thigh muscle.FemurPatellaCruciate ligamentLink this to previous section on synovial joints which included a cross section of the knee showing the synovial membrane and fluid.Tibia
23The structure of the elbow joint (hinge) The elbow is another complex hinge joint. The hinge between the humerus and ulna allows the arm to bend and straighten.The elbow also has a pivot joint between the ulna and radius which allows us to rotate the lower arm while keeping the upper arm still.A gliding action occurs between the humerus and radius.The whole joint is encased in a synovial capsule and held together by ligaments.HumerusRadiusDemonstrate movements to the class – get them to copy your movements.UlnaLigaments
24The structure of the hip joint (ball and socket) The hip joint is a large ball and socket joint.The head of the femur (long bone), which is shaped like a ball, fits into the socket (shaped like a cup) of the pelvis.PelvisFemurThe bones are covered in cartilage and reinforced with ligaments.
25The structure of the shoulder joint (ball and socket) The head of the humerus is shaped like a ball and fits into the cup-shaped socket of the scapula.The bones are covered in cartilage and held together with ligaments.ScapulaHumerusBall and socket come apartThe shoulder joint has more freedom to move than the hip joint and is capable of a greater variety of movement.However, this means it can dislocate more easily.
29Wrist, fingers and ankles The wrist is more than just a hinge joint – it can perform many complex movements, including flexion, extension, abduction and adduction.The fingers can be made into a fist (flexion) or straightened (extension). The fingers can be spread (abduction) or brought close together (adduction).The ankle is another complex hinge joint. The foot can bend down and bend up. It can also slide turn out (eversion) and in (inversion), as a result of gliding action between the tarsal bones.
30Joint movementJoints enable us to make an extremely wide range of movements under our conscious control.The different types of joints allow us to move in many different ways and to perform many different actions.Consider this dancer.The hinge joints at her elbows and her right knee are extended. Her left knee is flexed.There is abduction at her shoulders and right hip.The spine shows extension as the head moves back.
35Young gymnasts benefit from good flexibility. Joints and old ageMost people’s flexibility deteriorates as they get older. This is because the connective tissues around the joints become less elastic.Flexibility exercises and extended warm-ups before exercise can help, but ultimately, it becomes harder and harder to maintain the same levels of flexibility.Young gymnasts benefit from good flexibility.Some people, especially older individuals, may develop arthritis – a disease that causes pain, stiffness and inflammation around joints.It is usually hereditary, but injured joints that have not healed properly can be more prone to arthritis.
36Exam-style questions This diagram shows a cross section of the knee. b Name bones a, b and c.Name substance d.List the types of movement possible at the knee.Explain the role of cartilage in the functioning of the knee.adca) a = femur, b = patella, c = tibia. b) d = synovial fluid. c) The knee allows flexion and extension (or backwards and forwards). d) Cartilage protects the ends of the bones from wear and tear. It provides some shock absorption. Its smooth surface allows friction-free movement at the joint.As people age, flexibility tends to decrease as ligaments become less elastic. Flexibility can be improved by regular stretching exercises.2. Explain how age affects joint flexibility and suggest a way in which flexibility can be improved.
37Can you remember all these keywords? Joint – a place where two or more bones meet.Flexibility – the range of movement possible at a joint.Ligaments – strong, elastic fibres that join bones together.Tendons – non-elastic fibres that attach muscles to bones.Cartilage – connective tissue found at the ends of bones to protect them and enable smooth movement.Flexion – the action causing a limb to bend.Extension – the action of a joint / limb straightening.Abduction – the action of a limb moving outwards, away from the body.Adduction – the action of a limb moving in, towards the body.Rotation – the action of a limb turning around.