skeletal system good

© SSER Ltd. © SSER Ltd. B. Wing B. Wing

Cranium

Clavicle

Pelvis

Humerus

Radius

Femur

Ulna

Tibia

Patella

Fibula

Scapula(hidden)

Sternum

Vertebrae

Ribs

Phalanges

Metacarpals

Carpals

Tarsals

Metatarsals

Phalanges

There are 206 bones in the human body - the larger bones are:The Skeletal SystemThe Skeletal System

Skip to labelled diagram

The Cranium

Your skeleton is made up of bones, which are held together at joints by strong ‘straps’ called ligaments.

It is also known as the skull.

It is made up of 8 flatinterlocking bones.

The lower jaw-bone or mandible is hinged to the cranium, so you can chew.

The Rib CageThe Rib Cage

You have 12 pairs of ribs.

All are joined to the vertebrae at the back.

Most are also joined to the sternum at the front, except the bottom 2 pairs which are short floating ribs.

The skeleton is a rigid supporting framework of bonesinside the body, to which all the soft tissues andorgans are attached.

The Functions of the SkeletonThe Functions of the Skeleton

The skeleton can:

Together, the bones and muscles form a machinewhich can perform many different tasks.

grow in size. repair its own broken parts. lubricate its own joints. support internal organs.

Protection Support Movement Blood Cell Production

The 4 main functions of the Skeleton are:

ProtectionProtectionThe hard nature of bone means that the skeletoncan protect the more delicate parts of the body.

Examples:

The cranium (skull) protects the soft tissue of the brain.

The rib cage protects the delicate heart and lungs.

Without the skeleton, the body would beflabby and shapeless.

Examples:

The bones of the legs support the body.

The vertebrae support the head.

SupportSupport

The skeleton is jointed to allow us to move whenthe muscles attached to them contract.

Example:

The bones and joints work with muscles to enable us to walk, jog and sprint.

MovementMovement

The vertebrae allow us to bend, stretch and rotate our body.

Red and white blood cells are made in red bone marrow which is found at the ends of the femur and humerus and in the ribs, sternum, pelvis and vertebrae.

Femur::Located in the upper part of the leg.

Humerus::Located in the upperpart of the arm.

BloodBlood CellCell ProductionProduction

Red BoneMarrow

Movement:The joints in the spine allow bending and twisting.

Support:The spine is long and strong to support other body parts, e.g. the head.

Protection:The spine is hard and protects the nerves running through the middle, i.e. the spinal cord.

The Vertebral ColumnThe Vertebral Column

It is made up of 34 vertebrae, which are divided into 5 regions, each having its own function.

Cervical Vertebrae (7): Support the head, allowing it to bend and twist.

Thoracic Vertebrae (12): The ribs are connected to these - there is very little movement.

Lumbar Vertebrae (5): These are big and allow powerful twisting and bending of the back.

Sacrum Vertebrae (5): These form one solid mass which is fused to the pelvis.

Coccyx Vertebrae (5): These are the remains of our tail.

The Vertebral ColumnThe Vertebral Column

Bones start to grow inside the womb, where they begin as cartilage. Cartilage

Periosteum

Bone Marrow

Spongy Bone

Compact Bone

What are Bones made of?What are Bones made of?

Vitamin D helps build bone.

Calcium is a mineral which helps keep bones strong. Even as a fully-grown adult, the

bone structure is always changing, as vitamins and minerals are constantly replaced.

As you get older this turns into hard bone by a process called ossification. Bones will only grow properly as long as certain minerals and vitamins are eaten:

A poor diet will result in soft bones, whilst a balanced diet and exercise will make the bones harder.

Bone StructureBone StructureA photomicrograph of a section of bone showing

the strong concentric pattern laid downby the bone cells and the surrounding

calcium phosphate.

A photomicrograph of a section of bone showingthe strong concentric pattern laid downby the bone cells and the surrounding

calcium phosphate.

Calcium phosphateCalcium

phosphateBone cellsBone cells

Types of BonesTypes of BonesThere are 4 main types of bones in the human body.

Long Tubular BonesLong Tubular Bones – These are long and affect our overall height, e.g. the legs & arms (femur & humerus).

Short BonesShort Bones – These are smaller and are often found with many others, e.g. the feet & hands (phalanges).

Flat BonesFlat Bones – These are flat and are often found forming a protective surface, e.g. the skull (cranium) and pelvis.

Irregular BonesIrregular Bones – These are irregular in shape and have a specific function, e.g. the bones of the spine (vertebral column).

Each type has a different size and shape because they have different jobs to do:

JointsJoints

A joint is where two or more bones meet and

muscles act together to cause movement.

The human skeleton is jointed to allow movement.

Muscular contraction causes the bones to move about the joints.

The bones act as levers with the joints acting as pivots.

1. Fixed or Immoveable JointsThe bones at an immoveable joint cannot move - they overlap or interlock, and are held together by a tough fibre, e.g. the skull.

2. Slightly Moveable JointsThe bones at a slightly moveable joint can only

move a little - they are held together by strong straps called ligaments and are joined by protective

pads known as cartilage, e.g. the ribs.3. Freely Moveable JointsAt a freely moveable joint the bones move

freely.They are also known as synovial joints, andare the largest group of joints found in the

body, e.g. the hips, shoulders and knees.

Types of JointsTypes of Joints

There are 3 main types of joint found in the body.

Freely Moveable JointsFreely Moveable Joints

A typical synovial joint has the following characteristics:

Freely Moveable joints are also known as Synovial Joints. They are freely moving and occur where 2 or more bones meet. There are about 70 freely moveable joints in the human

skeleton.

2. Joint Capsule – The outer covering of the joint that holds the bones together and protects the joint.

3. Synovial Membrane – The inner lining of the joint capsule which also produces synovial fluid.

4. Synovial Fluid – The fluid which surrounds the joint and acts like an ‘oil’, lubricating it to allow easy movement.

5. Ligaments – These are elastic straps which join bone to bone, holding the joint together.

6. Tendons – These are non-elastic straps which join muscle to bone.

1. Cartilage – A material which covers the end of each bone, and which helps prevent friction between the joint.

Elbow Joint

This joint can be moved in the following ways:

Bend Straighten Circle Move away from the body Move towards the body

This joint can be moved in the following ways:

Bend Straighten

Hip Joint

Examples of Synovial JointsExamples of Synovial Joints

This joint can be moved in the following ways:

Bend Straighten Circle Move away from the body Move towards the body

This joint can be moved in the following ways:

Bend Straighten

Shoulder JointShoulder Joint Knee JointKnee Joint

This joint can be moved in the following ways:

Bend – but not as much as the knee & elbow. Straighten - but not as much as the knee & elbow. Circle – but not as much as the shoulder & hip. Move away from the body – but not as much as the shoulder & hip. Move towards the body – but not as much as the shoulder & hip.

Wrist Joint

Types of Synovial JointsTypes of Synovial Joints

KEY

Ball & Socket JointHinge Joint

Pivot Joint

Gliding Joint

Saddle Joint

Condyloid Joint

Freely moveable (synovial) joints can be divided into six groups depending upon how they move.

Ball and Socket joints are the most moveable joints in the body.

1.1. Ball and Socket Joints Ball and Socket Joints

They can move in all directions, e.g. the hip and shoulder joints.

Hinge joints work like a hinge on a door.

2.2. Hinge Joints Hinge Joints

They can only move in two directions, e.g. the knee and elbow joints.

This joint only allows rotation,e.g. the vertebrae of the neck.

3.3. Pivot Joints Pivot Joints

There is a little movement in all directions, e.g. the hand between the carpals.

4.4. Gliding Joints Gliding Joints

In these joints there is movement forwards, backwards and to the right and left, but no rotation, e.g. the thumb.

5.5. Saddle Joints Saddle Joints

Here there is a little movement in all directions, but there is no rotation, e.g. the wrist.

6.6. Condyloid Joints Condyloid Joints

The Synovial Joint of the KneeThe Synovial Joint of the Knee

The knee is a hinge joint.

Ligaments

TendonsTibia/Fibula

FemurCartilage

Synovial Fluid

Synovial Membrane

Patella

The Hip is a ball and socket joint.

Ligaments

Synovial Fluid

Tendons

SynovialMembrane

Pelvis

Cartilage

Femur

The Synovial Joint of the HipThe Synovial Joint of the Hip

Different types of synovial joints allow different kinds of movement. There are 6 basic types of movement that can occur at such joints:

1. Extension: Straightening or extending a limb.

2. Flexion: Bending or flexing a limb.

Example: the arm can be extended at the elbow.

Example: the leg can be flexed at the knee.

Movement at Synovial JointsMovement at Synovial Joints

3. Abduction: Moving a limb away from the centre line of the body.

4. Adduction: Moving a limb towards the centre line of the body.

Example: The leg can be moved away from the centre of the body at the hip.

Example: The arm can be moved towards the centre of the body at the shoulder.

5. Rotation: This is a turning or rotational movement

of a limb or body part.

Example: the head can be rotated at the neck.

6. Circumduction: The ability of a limb to be

moved in circles.

Example: the arm can move in circles at the shoulder.

What types of movement are possibleWhat types of movement are possibleat the following joints?at the following joints?

Extension Flexion Abduction Adduction Rotation Circumduction

Extension Flexion

Rotation

Ball and Socket Joint:

Hinge Joint: Pivot Joint:

The structure of the human skeleton helps sports people to perform in the following ways:

How does the Skeleton contributeHow does the Skeleton contributeto performance in Sport?to performance in Sport?

Support: Bone is hard which means it

creates a solid supporting framework inside the body.The legs support the body keeping it upright during the physical activity.

Movement: The skeleton is jointed so we can

move. The ability to move in a variety of ways is essential in most sports, e.g. run, sprint, jump, dodge, etc.

At the ‘tip-off’, players will use a dodge to move into space to receive a pass.The skeleton helps in a number of ways:

The legs keep the players upright and tall.

The ankle, knee and hip joints allow them to change speed, direction and to jump - to lose their opponents when dodging, sending or receiving a ball.

The neck supports the head allowing them to look around.

The shoulder, elbow and wrist joints enable the players to reach out and catch the ball.

BasketballBasketball

End of ShowEnd of Show

Copyright ©2003 SSER Ltd. and its licensors.All rights reserved.