THE SKELETAL SYSTEMUnit 1: Physical Education

THE SKELETAL

SYSTEM

DIVISION OF THE

SKELETAL SYSTEM

The skeleton is divided into

two main parts:

Axial skeleton

Appendicular skeleton

AXIAL SKELETONConsists of:•Skull: –8 Cranial bones–13 facial bones–Fuses together during childhood and adolescence

•Vertebral column–2 curves (cervical and lumbar) to deal with pressure from being upright

–7 cervical vertebrae (unfused), 12 thoracic vertebrae (unfused), 5 lumbar vertebrae (unfused), 5 fused sacral vertebrae and the coccyx is 4 or 5 fused vertebrae

•Rib Cage–12 ribs–Connect with vertebral column and sternum

APPENDICULAR SKELETON

Consists of:•Upper limbs:–60 bones (54 of which are in the hands and wrist).

–Small in size allow flexible hand movements. •Lower limbs:–60 bones (54 of which are in the feet and ankles).

–Large, strong and heavy with less flexibility. •Shoulder:–Includes the scapula, clavicle, sternum and humerus

–Flexible and allows rotational movements•Pelvis:–3 bones: Ilium, Ishium and Pubis–Weight bearing and child bearing (women) and not as flexible

1. Support – gives the body shape and provides structure for muscle to work against.

2. Protection of Organs – the brain in the skull, the heart, lungs, liver etc., in the ribcage.

3. Movement – the skeleton provides the structure for muscles to pull against and shorten, creating movement.

FUNCTIONS OF BONES

FUNCTIONS OF BONES

4. Storage of Mineral Salts – a

large percentage of bone is

made from Calcium and

Phosphorus, which can be both

stored and released from bone

tissue.

5. Production of Red Blood Cells

– Red Blood Cells are produced

in the bone marrow

TYPES

OF BONES

A. Short Bones

B. Long Bones

C. Sesamoid Bones

D. Flat Bones

E. Irregular Bones

SHORT BONES

Short Bones – bones of

the hands and feet, i.e. the

carpal (hand) and tarsal

(foot) bones.

They have no shaft and

are as long as they are

wide.

LONG BONES

Long Bones – have a diaphysis (shaft) and epiphysis (growth plate –the bones of the limbs in particular) e.g. the bones of the limbs –humerus, radius, ulna, femur, tibia, fibula.

Ribs, Phalanges, Metacarpals and Metatarsals.

The femur is the largest bone in the body.

SESAMOID BONES

Bones that are wrapped

in tendon or connective

tissue

The patella (knee-cap)

FLAT BONES

Flat bones are bones that

are indeed flat in shape and

provide either protection for

organs or muscle

attachment sites.

e.g. scapula, skull bones,

sternum

IRREGULAR BONESIrregular bones – “one of a kind” bones

The spinal column is comprised of 30 irregular bones – no two are exactly the same shape.

7 Cervical12 Thoracic5 Lumbar5 Sacral (fused)Coccyx

BONE HEALTH

•Epiphyseal Plates (Growth Plates) are at the centre of

long bones.

–Can affect bones growth if injured

•Osteoporosis- condition where bones become porous

and brittle

–Weight-bearing activity assist with healthy bone

growth and length

–Resistance activities can strengthen bones but if

overtrained or injured (stress fractures) can lead to

bone damage

JOINTSTypes of joints

JOINTS

Is where 2 or more bones meet.

Held together by ligaments.

Cartilage is found at the end of bones

Structure determines how it functions.

-Tightly fitting joints restrict movement and are stronger.

-The looser the fit the greater the movement, although the joint is weaker.

TYPES OF JOINTS

Synovial (moveable). Hip & knee, cervical and

thoracic vertebrae.

Cartilaginous (partially immoveable). Ribs and

sternum & lumbar vertebrae.

Fibrous (immovable). Skull, pelvis, radioulnar &

tibiofibular.

TYPES OF JOINT

Types of Joint Amount of movement Examples

Fixed or fibrous NoneSkull, pelvis, radioulnar

and tibiofibular joint

Cartilaginous SlightlyRibs attaching to sternum,

lumbar vertebrae

Synovial Freely

Hip and knee joints,

cervical and thoracic

vertebrae

SYNOVIAL JOINTS

Joints are lubricated by "synovial"

fluid.

Connections called "synovial"

joints are sturdy enough to hold

the skeleton together and at the

same time permit a range of

motions.

The ends of these joints are

coated with cartilages which

reduce friction and cushion

TYPES OF

JOINTS

Ball and socket

Hinge Joint

Pivot Joint

Saddle Joint

Gliding Joint

Condyloid Joint