There are 206 bones in an adult skeleton
At birth there are over 300 bones
As we mature to about the age of 2 years
some bones fuse to make up a single bone
and reduce the number to 206.
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Structural support – hold tissues in place
Movement – provide levers for muscles to pull
and move
Protection – ie: ribs protect heart, lungs
Mineral Reserve – calcium and phosphorous used
in energy production are stored in bone
Manufacture of Blood Cells – marrow inside long
bones produces new Red blood cells
Axial skeleton is comprised of the skull, vertebrae and
rib cage. 80 bones in all. Core muscles anchor here.
Appendicular skeleton is comprised of the arm and leg
bones plus the shoulder and pelvic girdle bones. 126
bones in all. Muscles for movement insert here.
Bone marrow is found as a yellowish (fat)
or red (blood) substance found inside the
long bones of the body. It manufactures
red blood cells for our blood stream.
Long bone – femur, humerus
Short bone – wrist carpal, foot
tarsal
Irregular bone –vertebrae
Sesmoid – patella (floating bone)
Flat bone – skull or rib
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True Ribs are connected by cartilage directly to the sternum.
There are 7 true ribs.
False Ribs are connected to the cartilage of the 7th rib that leads to
the sternum. There are 3 false ribs.
Floating ribs are located at the inferior level of the rib cage. They
are short and do not connect to the sternum (float). There are 2
floating ribs
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Cervical refers to the vertebrae in the neck region at the top of the spine. The first 7
vertebrae are cervical. C1 – C7.
Thoracic refers to the vertebrae in the rib area. There are 12, numbers T8 – T19.
Lumbar refers to the final 5 vertebrae in the lower back. L20 – L24.
Vertebrae protect the spinal cord and allow us flexibility to move
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Our skeleton is constantly replacing old bone cells with new to
ensure the integrity and strength of the our frame. The process is
known as remodelling. Osteoclasts cells dissolve old bone and
Osteoblasts deposit new bone cells. Our skeleton replaces itself
completely about every 3 years
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As we age the skeleton loses bone mass. More old bone is
dissolved than new bone made to replace it. After the age of 40
we lose more mass than we replace. This results in weaker more
frail bone.
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The condition of losing bone density due to aging is called
Osteoporosis. The result can lead to brittle bones, posture and
joint problems in later years of life. Exercise and diet (calcium
rich) along with proper medical attention can reduce the problem
as we age.
To slow done the bone loss process we should:
 Eat a diet balanced in calcium and vitamin D
 Exercise regularly
 Regular medical checks for bone density
 Avoid excessive alcohol or smoke
Cartilage is not bone but a hard yet flexible material found in the
skeleton to provide flexibility, cushioning and to prevent bones
from rubbing on bone.
Cartilage is very smooth and the surfaces glide over each other. It
can be found between most bone articulations (where bones meet).
It is found in all moving joints to allow pain free and friction free
smooth movement.
Cartilage does not have a blood supply so if damaged it does not
repair itself very well if at all. It is a common problem in sport
joint sprains of knee and shoulder.
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Ligaments are tough strands of connective tissue. They have little
give and are found in the joints connecting the bones in place so
the joint is stable and only moves in the desired motions.
Ligaments join bone to bone.
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When the joint is pushed past its extreme range of motion then the
ligaments that hold it in place as well as other soft tissues may
tear. This is known as a sprain. It results in swelling, heat,
redness and pain. Torn ligaments do not heal easily due to a lack
of blood flow to the tissue.
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Long bones are hollow to reduce weight and to
allow for blood cell production in the bone
marrow housed in its hollow interior.
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Ridges on bones can serve as locations for
tendons to attach (tendons connect the skeletal
muscles to the skeleton).
Ridges can also add
strength to the bone
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Tubersosities are bumps found on the bone,
spines are projections and grooves run the
length of a bone. All of these can serve as
attachment locations for the muscle to the bone
or places for nerves to locate.
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29 bones in the skull. Many are fused together
as in the skull and only a line exists between
them outlining the area
We can tell when a person’s skeleton has stopped growing by looking
at the growth plates on a long bone. Long bones grow by adding
bone at their ends. This plate is found between the shaft and head
of the bone. A gap indicates the bone is still growing. A solid line
indicates growth has stopped.
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Arthritis is an inflamation around the cartilage
surface or a roughening of the surface that
causes pain and inflamation around the joint.