By the End of This Section You Should

Joints

Learning Objectives:

By the end of this section you should:

• Have an understanding of the three types of joints (fibrous / cartilaginous and synovial).

• Be able to describe the structure of synovial joints.

• Be able to identify the five types of synovial joint and explain the types of movement they can make.

• Be able to apply your knowledge of joints to sporting movements.

• Be able to identify articulating bones involved in movement at the joints of the body.

Joints

•Joints are links between bones and skeleton.

•They act to allow movement but also work to stabilise areas of the body.

•Note – freely moveable synovial joints are located in the limbs of the Appendicular skeleton, while immoveable and slightly moveable joints are more commonly found in the Axial skeleton.

Types of Joints

Joints are classified in three ways according to the balance that they allow between stability and mobility

Class of Joint / Mobility / Stability / Examples of the skeleton
Fibrous
Cartilaginous
Synovial

Task – can you identify two different types of synovial joints and explain how they enable you to perform skills in two different sporting activities.

•

Feature / Structure / Function
Ligament / A band of strong fibrous tissue
Synovial Fluid / To reduce friction between the articular cartilage and the joint
Articular Cartilage / Glassy smooth cartilage that is spongy and covers the ends of the bones in the joint
Joint Capsule / The fibrous capsule helps to strengthen the joint, while the synovial membrane lines the joint and secretes synovial fluid

Structure of Synovial Joints

As well as the four features we have already looked at, some synovial joints have additional feature:

The Shoulder Joint (Ball and Socket)

•Bursa

–A with synovial fluid that contains a thin line of film of . Its function is to prevent friction at sites in the body where ligaments, , tendons or might rub together.

The Knee Joint (Hinge)

•Meniscus

–A wedge of white that improves the fit between adjacent bone ends, making the joint more and wear and tear on joint surfaces.

The Elbow Joint (Hinge)

•Pad of Fat

–A fatty pad that provides between the fibrous capsule and a or .

Types of Synovial Joint

Synovial Joints have many common structural characteristics. However, the shapes of the articulating surfaces within the joint capsules vary considerably and this determines how much movement is allowed at a particular joint.

For this course we need to know the five different groups these joints can be grouped into.

• Ball and Socket

• Hinge

• Pivot

• Condyloid

• Gliding

Joint / Description / Mobility / Example / Picture
Ball and Socket /

Hinge /

Pivot /
Condyloid /
Gliding /

Main Movements

Name / Type of Movement
Of a joint makes part of the body move in a forwards direction from the anatomical position
Of a joint makes a body part move in a backwards direction

Note – the knee joint is the only exception to this rule where flexion moves the lower leg backwards and extension moves the lower leg forwards.

Name / Type of Movement
Occurs when the shoulder is already flexed with the arm parallel to the ground and the shoulder joint moves towards the middle of the body
Occurs when the shoulder joint with the arm parallel to the ground moves away from the middle of the body

Tip – in horizontal flexion and extension the fingers are already pointing at the horizon

Name / Type of Movement
Of a joint makes a body part move away from the midline of the body in the anatomical position.
Of a joint makes a body part move towards the midline of the body.

Name / Type of Movement
Of a joint is when a body part turns about its long axis from the anatomical position. For example, when using a screwdriver, rotation is occurring at the shoulder joint as the arm turns about an axis that travels straight through the arm from the shoulder to the wrist.

Name / Type of Movement
Of a joint makes a body part move from the anatomical position, creating a cone shaped movement. The joint performing the circumduction remains still whilst the furthest end of the body part moves in a circle.
Name / Type of Movement
In the anatomical position supination of the radio-ulnar joint makes the palm face forwards or upwards
In the anatomical position pronaiton of the radio-ulnar joint makes the palm move to face backwards or downwards
Name / Type of Movement
An anatomical term unique to the spine. It involves bending the spine sideways as you might do as part of a warm up to mobilise your spine.
Name / Type of Movement
These terms are unique to the ankle term. Dorsiflexion of the ankle joint makes the foot move towards the shin as when you walk on your heels.
Plantar flexion of the ankle joint makes the foot move away from the shin as when you walk on you tiptoes.

Task – can you complete the table below summarising the movements of the major joints of the body that you need to know.

Joint / Movements Possible
Wrist
Radio-ulnar
Elbow
Shoulder
Spine
Hip
Knee
Ankle

Task – can you identify the names of the highlighted joints e.g. elbow the type of joint it is e.g. hinge and the type of movement that is shown in the picture e.g. flexion