Cervical Vertebrae
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The cervical vertebrae is the first set of vertebral
bones of the spine, located inferior to the skull.
The cervical vertebrae consists of 7 vertebral bones,
denoted as C1, C2, C3, C4, C5, C6, and C7.
These bones “stack” up each other, starting with C1
and ending with C7.
The primary function of the cervical vertebrae is
protection of the spinal cord and support of the body.
These vertebrae can flex and extend to allow for
movement.
Furthermore, the cervical vertebrae are generally smaller
than the other vertebrae.
Small anatomical differences do exist between each of the
cervical vertebra, but for the most part they are similar. C1
is unique in that it contains the joint between the spine and
the skull, since it is the first bone of the vertebral column.
Thoracic Vertebrae
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The thoracic vertebrae is the set of vertebrates
following the cervical vertebrae and is the middle
segment of the spine.
The thoracic vertebrae consists of 12 vertebral bones,
denoted as T1, T2, T3, T4, T5, T6, T7, T8, T9, T10,
T11, and T12, these bones increase in size and width
from T1 to T12.
Furthermore, the thoracic vertebrae are of intermediate
size, larger than the cervical vertebrae and smaller than
the lumbar vertebrae.
The thoracic vertebrae houses the spinal cord and
protects the spinal cord. During movement, the thoracic
vertebrae can flex and move.
Lumbar Vertebrae
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The lumbar vertebrae is the third curve of the spine
and follows the thoracic vertebrae.
The lumbar vertebrae consists of 5 vertebral bones,
denoted as L1, L2, L3, L4, and L5.
These are the largest vertebral bones and each
individual bone increases in size from L1 through L5,
like the cervical and thoracic vertebrae.
The function of the lumbar vertebrae is the protection of
the spinal cord. Additionally, the lumbar vertebrae allows
for much of human body motion and supports much of the
human body’s weight.
Sacral Vertebrae
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The sacral vertebrae is the fourth and final curve of
the vertebral column, located at the base of the spine
following the lumbar vertebrae.
The sacral vertebrae consists of one bone, known as
the sacrum.
Initially, in children, the sacrum is made up of 5
separate bones.
However, as the body ages, the 5 bones fuse to
collectively form the sacrum.
For this reason, the sacrum is divided into 5 regions,
the S1, S2, S3, S4, and S5.
The sacrum is a triangularly shaped bone located
between the hip bones.
The function of the sacrum is protection and support of the
body. Interestingly, the 5 separate bones of the sacrum
begin to fuse during the late teen years and are usually
completely fused by the age of 25 or 26.
Coccygeal Vertebrae
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The final portion of the spine or vertebral column is
the coccyx.
The coccyx, also known as the tailbone, is composed
of 3 or 5 bones fused together.
Although for the most part the bones are fused
together to form a single coccyx, and the coccyx is
referred to as one bone in anatomical texts, in some
adults the coccyx consists of separate, unfused
bones. However, this is most likely not the norm.
Since human’s do not contain a tail, the coccyx or tailbone
is sometimes referred to as a vestigial structure. However
the coccyx has many functions in the human body, such
as providing protection, support while sitting, and serving
as the location of many attachment sites for ligaments and
muscles.
A overview of the Spinal Column.