BTEC Sport and Exercise Science

Anatomy Skeleton and Joints

Session 2 Part 2

2nd Joke of the day!!

• What does a female skeleton wear?

• A VERTEBRA

JOINTS• Joint - where two or

more bones meet.• There are three main

types of joint.• Classified according to

the degree of movement permitted.

• Skeleton works with the muscular system to bring about movement at joints.

Types of joint

Fixed or fibrous joints:• These joints are very stable and allow no

observable movement.• Bones of the joint interlock or overlap.• Often joined by strong tough fibers called sutures.• E.g. joints of cranium.

Types of jointCartilaginous or slightly

moveable joints:• These are joined by a

tough, fibrous cartilage providing stability and shock absorption properties.

• No joint cavities - the bones of the joint are held together by cartilage and ligaments.

• A small amount of movement usually exists.

Types of jointSynovial or freely movable

joints:

• Most common type of joint in the body.

• The bones can move quite freely.

• Wide range of movement from these joints.

• Very important in terms of physical activity.

• E.g. shoulder and elbow joints.

Synovial Joints

• In spite of differences from joint to joint synovial joints all have the same basic structure:

• an outer sleeve or joint capsule which helps hold the bones in place and protects the joint.

• Synovial membrane. This is the lining of the capsule which secretes a slippery liquid called synovial fluid.

• Synovial fluid - acts as a lubricant so bones can move easily and is also important in the maintenance and nutrition of the joint.

Synovial joints

• Joint cavity - this is the gap between the bones, filled with synovial fluid.

• Thin layer of Hyaline cartilage - facilitates smooth gliding movements between the bone ends, with minimum resistance.

• Ligaments - attached to each of the joint bones. Aid in joint stability and prevent excessive joint movement. Slightly elastic so that the bones can move the way they should.

Diagram of a typical synovial joint!

Joint Cavity

Synovial joints

• There are 6 different types of synovial joint:

– Hinge

– Pivot

– Ball and socket

– Saddle

– Gliding

– Condyloid

Hinge

• These joints allow movement in one plane only.

• Joint can swing open until straight like a door hinge.

• Strong ligaments exist to prevent any sideways movement.

• For example the elbow

• Can you think of any others?

Pivot• These joints allow rotation only.

• A ring on one bone fits over a peg on the other allowing rotation.

• Examples of this are the first two vertebrae in your neck and the joint beneath your elbow move in a semicircle motion by twisting against each other.

Ball and socket

• Ball and socket joints allow the widest range of movement.

• The round end of one bone fits into a hollow in the other.

• Joint movement in all directions is possible.

Saddle

• The bone ends are shaped like saddles and fit tightly together.

• Movement is from back to front and side to side.

• Can you think of a joint in the body that is a saddle joint?

Gliding• Flat surfaces of the bone

glide past one another.

• Little movement in all directions.

• For example the bones in the wrist and ankle known as ????????

Condyloid• Bump on one bone

sits in the hollow formed by another bone or bones.

• Movement in two planes (front/back and side/side).

• Ligaments prevent rotation at the joint.

Joint mobility - HomeworkJoint mobility - Homework• Each joint has its own characteristic range and type of Each joint has its own characteristic range and type of

movementmovement• Individuals demonstrate varying degrees of movement from Individuals demonstrate varying degrees of movement from

each joint.each joint.• There are 7 factors that affect joint mobility these being: shape There are 7 factors that affect joint mobility these being: shape

of joint surfaces, impinging bony structures around joint, of joint surfaces, impinging bony structures around joint, limiting effect of muscle, ligaments, temperature of joint, age limiting effect of muscle, ligaments, temperature of joint, age and gender.and gender.

• Task - comment on each of the above with relation to Task - comment on each of the above with relation to joint mobility - how do you think they will affect joint joint mobility - how do you think they will affect joint mobility?mobility?