Transcript Skeletal system powerpoint.ppt

THE SKELETAL SYSTEM
The functions of the system
1. To provide structure and protection.
2. To provide attachment for muscles so allowing
movement.
3. To produce blood cells .
4. To store calcium , phosphorous and other
minerals
The Skeleton
• The skeleton consist of some 206 bones,
we have more separate bones when we are born
than when we are adults ; many bones fuse
together as we mature.
• The skeleton does not fully form and stop
growing until we are in our mid twenties .
• The bones are formed from living tissue which
requires a good supply of nutrient rich blood to
help maintenance in adulthood and growth in
childhood.
The skeleton is divided up into
two sections
1.The Axial skeleton represented
here in green is made up from
The skull
The rib cage
The spine
The sternum
The hyoid bone
2.The Appendicular in purple is
made up from
The pectoral girdle or shoulder
blades and collar bone
The arms and the hands
The pelvic girdle or pelvis
The legs and the feet
Cells and Bone Growth
•
•
•
•
Bone cells are called Osteocytes .
Bones are in a constant state of degeneration and regeneration.
Bone cells which build bone are called osteoblasts
Bone cells which reabsorb bone are called osteoclasts.
The development of bone is called osteogenesis or ossification . This process
begins before birth and is not complete until our early to mid twenties when the
final bones fuse together.
Different shapes of bone develop from different patterns differentiated by
the way fibres are laid down and then calcified. Eg long bones develop from
the cartilage model where cells and then fibers are laid down in lines .
There are two main processes in bone development:
1.
Secretion of collagen fibers by osteo blasts which replace the original foetal
cartilage and membrane .
2. The calcification of those collagen fibres.
The Types of bone tissue
There are two types of bone tissue :
1. Compact : found on the outside of bones forming a very
dense and strong material
2. Cancellous or spongy : found in the ends of all long
bones and in the middle of all others, forming a lighter but
very strong tissue which houses bone marrow .
Shapes of bone
1. Long bones : Eg the phalanges , femur, humerus , radius ,
and the clavicle.
2. Short bones :Eg the carpals and the tarsals.
3. Flat bones : Eg the scapulae, the pelvis ( ilium , ischium and pubis )
the skull, the sternum and the ribs .
4. Irregular : Eg the vertebrae and the bones of the face .
5. Sesamoid : found within tendons , the hyoid in the neck and the knee
cap or patella .
The spine
The spine is divided
up into sections . All
vertebrae share
common features but
each section has a
different shape in
order to carry out
different tasks .
The sacrum is formed
from 5 bones fused
together , they help
form the pelvic girdle
The 7 cervical
vertebrae are shallow
and broad
They have lots of
mobility but also
support the cranium.
The 12 thoracic vertebrae
have spinous processes
which face downwards
, they don’t have a lot of
mobility as they articulate
with the ribs.
The 5 lumbar
vertebrae have much
bigger bodies and
have more movement,
taking the strain from
bending and lifting
The 3 to 4 bones of
the coccyx may be the
end of our tails !
All the vertebrae share the same features
but have different shapes .
Discs contain fluid which can leak , the gel like
cushion which contains this may protrude due
to stress or trauma and cause great pain due to
inpingement on spinal nerves .
POSTURAL FAULTS
Posture may be defined as the relative position or attitude of the body at any one
period of time .
Correct posture is the position in which minimal stress is applied to the joints.
Good posture maintains the body in balance and avoids stress.
Poor posture places inappropriate stresses and strains on the spine, joints and
musculature . This can effect the internal organs as well as the nervous system ,
causing digestive disorders , poor bladder control and difficulty with respiration .
Postural faults include the following : Muscle weaknesses
1. Kyphosis
a. advanced ( Dowager,s Hump)
b. thoracic
are part and parcel of
postural difficulties
and have many causes.
Lordosis
lumber spine
2. Hypo kyphosis
flat thoracic back
3. Hypo lordosis
lack of lumbar curvature Hyper extension
‘sway back’ knees’
In addition :
Scoliosis
sideways curvature
a. structural.
b. functional.
(Seen on next page)
Ideal
alignment
2.Flat back
1.Kyphosis
Hypo lordosis
Lordosis
/kyphosis
3.Sway back.
Exaggerated
curvatures of the
spine may have
several causes .
1. Congenital
(structural )
2. Trauma
3. Postural
(functional)
These curvatures
can cause pain and
discomfort , as spinal
nerves are placed under
pressure , muscles contract
to protect the spine.
Dowager’s Hump
This problem is most
commonly linked to
osteoporosis and loss of bone
density in older women.
As a result of multiple anterior
thoracic compression
fractures , the sufferer begins
to stoop.
The developing kyphosis and
advanced osteoporoasis is
characterised by pain and
discomfort and a resultant
decrease in height.
Hyper extension
Winged scapulae
Usually caused by injury
or trauma and weakened
musculature particularly
trapezius and serratus
anterior .
This is where a joint is
extended beyond its
normal range of
movement.
The most common
joint to be hyper
extended is the knee.
Sports injuries are the
most common cause of
this and may include
tears to the ligaments
and tendons .
This kind of injury may
be mild and will heal
on its own, however
more severe traumas
may require surgery.
The Skull
The rib
cage
There are 12 pairs of ribs
7 pairs of true ribs and 3 pairs of
false ribs plus two pairs of floating
ribs .
The ribs articulate with the thoracic
vertebrae at the posterior and with
the sternum at the anterior.
The sternum
consists of 3 bones.
• The manubrium
• The stern
• The xyphoid.
In the anterior , the true ribs attach
directly to the sternum via costal
cartilage.
The Pectoral Girdle
The pectoral girdle
Is formed by the clavicles and the
scapulae, together they form a highly
mobile structure with the only
attachments being at the acromion of
the scapulae and the manubrium of
the sternum.
This together with the ball and socket
joint of the humerus and scapulae
allows for the very varied and broad
range of articulation for both shoulder
and arm.
Ball and
socket
synovial joint
The arms are formed from three bones .
The humerus forming the upper arm
the radius and the ulna ,the lower arm.
The ulna and the radius articulate at the
elbow and with each to allow us to turn our
hand up
( supinate) or down
( pronate ).
The short bones at the wrist are the
carpals . there are 8 bones here .
The other bones are the 5 metacarpals
and the14 phalanges .
The wrist and hand
The carpals
These 8 short bones
Have a very restricted area to
move around in.
On the palmer side they are
arranged in a concave shape ,
the vessels , tendons and
nerves of the arm and hand all
have to pass through this carpal
tunnel . This can cause
problems when the hand and
forearm is over used .
The Pelvic Girdle
The pelvis consists of two identical sets of 3 bones
fused together, they are :
•The Ilium
•The Ischium
•The Pubis
These fused bones are sometimes known as the
innominate bones or the coxal bones .
Together with the sacrum this forms the pelvic
girdle.
The ball
and
socket
joint of the
hip.
Ilium
ischium
Pubis
The legs
The legs are formed from three bones .
The largest bone in the body which is the
Femur is also the largest long bone .
Long bones tend to be slightly curved in
order to deal with stress, this is especially
the case for the femur.
The lower leg is formed from the Tibia or
shin bone and the Fibula to the lateral side
of it .
The feet
The bones of the ankle are the Tarsals
there are 7 tarsals including the heel bone or calcaneus
The other bones are the Metatarsals and Phalanges .
Examples of diseases and disorders
• Osteoporosis is a disorder which is characterised by thinning of the
bone through an in balance in the bone cells which form bone(
osteoblasts ) and the bone cells which reabsorb bone ( osteoclasts).
This is added to by a lack of calcium and often caused by a decline in
oestrogen and progesterone in women after the menopause. This
results in a tendency to fracture and changes in posture due to
crumbling .
• Osteo arthritis is a disorder which effects the joints , usually beginning
in the larger joints such as knees, hips and spine . This is
characterised by a wearing away of the cartilage on the ends of the
bones where they join to form the joint. This then leads to a leaking of
synovial fluid( lubricating fluid in the joint) a general drying out .Growth
of bony spurs with inflammation and pain on movement.
• Rheumatoid arthritis : Known as an auto immune disorder which
results in bouts of inflammation ,when the synovial membrane is
attacked .This normally begins in the smaller joints, hands , feet,
elbows .
• Gout : arthritis which is caused by an excess of uric acid in the blood
, this forms crystals which appear within the tissue layers causing
inflammation and pain .
(Sometimes known as the rich mans disease, as it is linked to red
meat, red wines, sea food , cream etc ).
• Ankylosing spondylitis : a type of arthritis more similar to
rheumatoid than to osteo which effects the the sacro iliac ,spinal and
costa vertabral joints. This leads to chronic inflammation which builds
fibrous scar tissue over a long period of time . Eventually , unless
some mobility is encouraged through treatment then bones will fuse
together and mobility will be lost for good .
Fractures
Bones all have specific areas which are more vulnerable to fracture.
The neck of the femur , a common place for fracture in the elderly
when they fall.
The distal end of the radius , known as a ‘Colles Fracture’ , when
people put a hand out to break a fall.
The centre of the clavicle …. often the same reason as above .
The scaphoid carpal …..common when there is a fall on to an
out stretched hand.
The distal ends of either the tibia or fibula when the ankle is badly
twisted.
Main types of Fracture
• Simple : where there is a clean break across a bone .
• Compound : Where the bone breaks and pierces through the
surrounding tissues emerging through the skin .
• Comminuted :where a bone breaks in many different places.
• Green stick : where a young bone has an incomplete break or split
due to the softness of the bone .
• Impacted : where the ends of the bone are shunted into each other
• Complicated : where the bone is broken in many places , with un
even sections damaging the surrounding tissues and organs .
Dietary
Trauma
Osteomalacia
Rickets
Loss of limbs
Prosthesis
Scleroderma
Dermal
Systemic
Developmental
Osteogenesis
imperfecta
Uncommon pathologies
Auto immune
Psoriatic
arthritis
Congenital/ viral
Cellular
Systemic lupus
Systemic
/cellular
Pagets
disease
Spinal stenosis
There are three categories of joint
1.
Fixed fibrous : these are joints which have no movement in them .
They are found in areas where bones have fused together. Eg The
cranium , where these joints are called sutures.
The teeth into the maxilla and mandible . Or the coxal bones of the
pelvis .
2.
Cartilaginous : these are joints characterised by the inclusion of a
fibrous cartilage disc and the capability to have slight movement.eg
the pubis symphyisis of the pelvis or the discs between the
vertebrae. The spine has a range of movement as a whole but not a
great range within the individual joints .
3.
Synovial joints : these are joints which share common features ,
they have capsules , membrane and fluid . They are articulating
joints other wise known as freely moveable .
SYNOVIAL JOINTS
There are 6 types
1. Hinge : phalanges, knees,
elbows.
2. Ball and socket: hips,
shoulders.
3. Gliding : sterno clavicle
sterno/ vertebral costal ,
carpals and tarsals.
4. Saddle : trapezium of the
thumb .
5. Pivot : atlas / axis ,radial
ulnar at the elbow .
6. Elipsoid : radius and the
scaphoid carpal.
This last type is known as a
condyloid joint.