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Anatomy 101
The spine is one of the most important parts
our our body. It has three main functions:
- Protects the spinal cord
- Gives the body structure and support
- Allows us to move freely
The Bones and Joints
The spine is made of 33 bones called vertebra
that are stacked one above each other. There are:
- 7 cervical vertebra in
the neck,
- 12 thoracic vertebra in
the middle back and
- 5 lumbar vertebra in the
low back.
The sacrum is a wedged shaped
bone in the pelvis made of 5 fused verterbra.The the tail
end of the spine (literally) we have the coccyx
made of 4 fused coccygeal vertebra. The vertebra are given
names based on their position in the spine. L1 is the first
lumbar vertebra. There are 2 bones that have special names
because of their special function the atlas
(C1) which holds up the head and the axis
which allows the head to rotate from side to side.
Here
you can see 2 vertebra stacked on on top of the other. The
vertebra are joined to each other by 3 joints. The large disc
in the front which is like a soft cushion and provides support
and absorbs pressure. The disc has a poor blood supply and
recieves it's nutrition via sucking the nutrients from the
bony when you move. Behind the disc there are 2 facet
joints. The facet joints guide the movement of the
vertebra and have a large supply of nerves which feed you
brain with information about where your spine is and how it
is moving. Your brain uses this information when it is deciding
how your organs should function. Some
amazing research by Dr Akio Sato has been done in this
field.This is why is it is so mportant to maintain the normal
movement of you spine.
Between the facet joints and the disc is a
gap called the intervertebral foramen or
the IVF for short. The spinal nerves exit
the spinal canal through the IVF.
There are a number of bumps on each vertebra.
You can see the transverse and spinous processes
in the picture. The muscles and ligaments of the spine attach
to these bumps.
The Ligaments
There are a number of ligaments that cross
between two vertebra. The ligaments hold the bones together
while still allowing the joints to move. Some of the ligaments
cross the intervetebral foramen and reduce the space the spinal
nerves have to exit the spinal canal. When there is joint
restriction the ligaments can rub twist and squash the nerves
reducing there ability to carry healthy information from the
brain to the body or the body back to the brain.
WIth age and lack of exercise the ligaments
become shorter and harder. Make the joints stiffer. In the
long term tight and stiff ligaments pull on the bones and
produce bone spurs. Exercise and adjustments to maximise the
health of the ligaments will minimise the effects of osteoarthrits
in the future.
The Muscles
There are multiple layers of muscles in the
back. Some are for supporting our spine and are called postural
muscles or core muscles others are for moving our spine and
are called the prime movers. The muscles are arranged in different
patterns to bend our spine forwards backwards, sideways and
rotate to each side.
Like all muscles of the body the spinal muscles
require good exercise and stretching to maintain their health
and the health of your spine. The Straighten
Up Australia program has a series of exercises designed
to be completed in everyday in three minutes. Studies around
the world have found the people doing these exercises feel
stronger and have better posture.
The Nerves
The Spinal Cord
The spinal cord is the information superhighway
between you brain and your body. Without it you could not
move any part of your body and your organs could not function.
It is made of millions of nerves.
The spinal cord is protected by the bony spinal
canal formed by the vertebra that are stacked one on top of
the other. It is also protected by the dura mater,
a tough covering around the cord. Between the dura
mater and the spinal cord is the cerebro spinal fluid
(CSF) The CSF is important for protection of the
central nervous system (CNS), which includes
the brain and the spinal cord and feeds the CNS with nutrients
from the blood.
The Peripheral Nerves
The spinal nerves convey
information between the central nervous system and the rest
of the body. The spinal nerves exit the spinal canal through
each of the intervetbral foramen between each pair of vertebra.
Like the tributaries of a river the small spinal nerves form
larger nerves, such as the sciatic nerve,
which runs down the buttock into the leg. This is how your
brain controls every single cell and organ in you body.
The following chart describes which spinal
nerves innervate (supply) which parts of the body. You will
notice that all the body parts actually recieve information
from more than one spinal nerve and the nerves travel a great
distance to get to the organ they are supplying. This is why
the actual problem in the spinal can be a long way away from
you you feel the problem.
Co |
Pituarty gland, scalp, brain, ears, eyes |
Atlas (C1) |
Head, eyes, ears, tongue, heart |
Axis (C2) |
Face, neck, ears, shoulders, diaphragm |
C3 |
Face, neck, ears, chest, diaphragm |
C4 |
Neck, vocal cords. shoulder, upper arm, diaphragm |
C5 |
Shoulders, arms, tonsils |
C6 |
Shoulders, arms, wrists, hands, thryoid |
C7 |
Shoulders, arms, elbows, wrists, hands |
T1 |
Head, neck, heart, thyroid, oeosophagus, trachea,
heart, elbow and hand |
T2 |
Head, neck, heart, lungs, upper arms |
T3 |
Head, neck, heart, lungs, chest, upper arms |
T4 |
Head, neck, heart, lungs, gall bladder, upper arms |
T5 |
Head, neck heart, liver, oeosphagus, blood circulation,
upper arms |
T6 |
Oesophagus, stomach, spleen, pancreas, duodenum,
middle back |
T7 |
Stomach, spleen, pancreas, duodenum, liver, gallbladder,
middle back |
T8 |
Stomach, spleen, pancreas, liver, gallbladder, adrenal
glands, middle back |
T9 |
Stomach,spleen, pancreas, adrenal glands, gall bladder,
reproductive organs, liver, small intestine |
T10 |
Stomach,spleen, pancreas, small intestine, reproductive
organs, appendix, large intestine and leg |
T11 |
Kidneys, reproductive organs, legs, small & large
intestine, bladder, adrenal gland, ileoceacal valve |
T12 |
Kidneys, reproductive organs, legs, small & large
intestine, bladder, upper & lower back, ileoceacal
valve |
L1 |
Abdomen, reproductive organs, legs & feet, large
intestine, bladder |
L2 |
Abdomen, reproductive organs, legs & feet, large
intestine, bladder, appendix |
L3 |
Reproductive organs, legs & feet, large intestine,
bladder, prostate |
L4 |
Buttocks, legs & feet, prostate, muscles of the
lower back |
L5 |
Buttocks, legs & feet, toes, prostate |
Sacral Plexus |
Buttocks, legs & feet bladder, prostate, reproductive
organs, bladder, rectum and anus |
Coccygeal Plexus |
Rectum and anus |
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