Secondary Two

Topic: Bones and Joints

Sub Topic: Synovial Joints

• Students will be able to:

• identify that synovial joints are freely

moveable joints;

• understand the types of movements

allowed by the various types of joints;

• understand what is contraindicated

exercises and why it is not

recommended to perform.

• Ball and socket joints

• Hinge joints

• Pivot joints

• Gliding joints

• Flexion and extension

• Rotation and Circumduction

• Abduction and adduction

• Flexibility

• Contraindicated exercises

• One conversation

• Ask if you do not understand

• No sleeping

WHAT IS SYNOVIAL JOINTS?

RECAP:

Synovial Joints

Also known as freely moveable joints

Allow a large degree of movement

Exist 4 different types which allow

different kind of movement

◦ Ball and socket

◦ Hinge

◦ Pivot

◦ Gliding

Covering in next lesson

Synovial Joints

Parts of the typical moveable joint

include:

Synovial Joints

The 5 examples:

BALL AND SOCKET JOINTS

Types of Synovial Joints

Ball and Socket Joints

As the name goes, this joint consist of “a

ball” and “a socket” (a cup-like depression)

The joint allows a very large degree of

freedom to rotate

Two examples are located at the shoulder

and hip

Ball and Socket Joints

Shoulder: Humerus and

Scapula

Hip: Femur and Pelvis

Ball and Socket Joints

As seen in the diagram, the femur is

more deeply embedded into the pelvis

than the pair at the shoulder

This results in the hip joint to be a

stronger joint as it need to carry the

weight of the upper body

But being more deeply embedded also

results in a smaller degree of freedom

to rotate a compared to the shoulder

joint

HINGE JOINTS

Types of Synovial Joints

Hinge Joints

Works similar to the concept of a

adoor hinge (thus the name)

Moves in a single axis to bend or

straighten

Hinge Joints

Examples of hinge joints:

◦ Elbow (between ulna and humerus)

◦ Knee (between femur and tibia)

◦ Fingers / toes

PIVOT JOINTS

Types of Synovial Joints

Pivot Joints

Pivot joints allow the rotation of the

bones without changing of angle

Pivot Joints

Examples of pivot joints:

◦ Elbow (between radius and humerus)

◦ Neck (between atlas C1 and axis C2)

GLIDING JOINTS

Types of Synovial Joints

Gliding Joints

Also known as a planar joint

Formed where 2 bones meet at flat or

almost flat surfaces

Allows sliding in almost any direction

within the plane

Gliding Joints: Ankle and

Wrist

TYPES OF MOVEMENTS

Types of Movements

Flexion vs Extension

Rotation vs Circumduction

Abduction vs Adduction

Anatomical Position

The types of movements are decided

based on the anatomical position of

the human

◦ Imagine lying down, facing up

◦ Palms facing up

Flexion

Refers to the action of bending of the

joint when body is lying down in

anatomical position

◦ Fingers

◦ Wrist

◦ Elbow

◦ Shoulder

◦ Trunk (hip)

◦ Knee

Extension

Refers to the action of “straightening

the joints” back to the anatomical

position

Extension

Hyper-Extension?!?!

When the joint is extended beyond the

anatomical position

Rotation

Rotation refers to the turning around

an axis

Abduction / Adduction

Abduction and adduction are two terms that

are used to describe movements towards or

away from the midline of the body.

◦ Abduction is a movement away from the midline

◦ Adduction is a movement towards the midline

Circumduction

Circumduction is the combined action

of flexion, extension, abduction and

adduction of the limbs which results in

a circular motion

CONTRAINDICATED EXERCISES

Contraindicated Exercises

A contraindicated exercise is a movement that is not recommended because it is potentially dangerous. It may involve:◦ Extreme movements that cause extension or

flexion of a joint beyond its normal range e.g. full circle neck rotations, back arches, toe touches, deep knee bends and frog jump repetitions

◦ Movements that involve excessive, rapid or repetitive twisting around a fixed base e.g. wall slaps, trunk rotations

◦ It may come as a form of exercise or stretching

Contraindicated Exercises

Hurdler stretch

◦ Aimed to stretch the hamstring

◦ The flexed (bent) knee results in a rotated knee

◦ Stresses the cartilage and especially ligaments

Contraindicated Exercises

Quad stretch with both knees flexed

◦ Aimed to stretch the quads

◦ Places a big portion of body weight on the knees

while stretching

◦ Chances of over-stretching the ligaments

Contraindicated Exercises

Forward neck stretch

◦ In our neck, the first two vertebrae are known as

C1 and C2

◦ C1 rests on C2, and stands a chance to be

“dropped out” if the head suffers a sudden jerk

forward

◦ In addition, there is not much muscles at the

back of the neck that requires stretching

Contraindicated Exercises

Not recommended to rotate the head /

push the head forward for stretching

On similar reasons, the hands are not

to be “cupped” behind the head when

doing sit up

Contraindicated Exercises

Lunges / squats

◦ Aimed to strengthen the quads and

hamstrings

◦ Common mistake of having knees moving

too far forward (beyond the toes)

◦ Results in knee being over flexed and

bearing the full body’s weight at the knees

◦ Over stretches the ligaments

Contraindicated Exercises

Contraindicated Exercises

Contraindicated Exercises

Many other forms of exercises such as:

◦ Star jump

◦ Duck walk

◦ Back raises

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Lets Recap

• Ball and socket joints

• Hinge joints

• Pivot joints

• Gliding joints

• Flexion and extension

• Rotation and Circumduction

• Abduction and adduction

• Flexibility

• Contraindicated exercises