L1 through L5
L1 through L5 is a reference to the five (L1, L2, L3,
L4, L5) vertebrae (bones that form an opening in
which the spinal cord passes) that are near an area of
the body known as the loin. The letter "L" stands for
"lumbus," which is Greek for "loin." The loin is the part
of the back between the lowest pair of ribs of the
thorax (chest) and the top of the pelvis. The pelvis is a
massive bone made of hip bones on each side and the
front, while the back part is made of the sacrum (a
triangular bone) and coccyx (a beak shaped bone). L1
refers to the 1st lumbar bone, L2 to the 2nd lumbar
bone, L3 to the 3rd lumbar bone, and so on, until L5,
which is the last lumbar bone.
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These numeric levels are often mentioned on imaging studies of the spine such as
computerzed axial tomography (CT) scans or magnetic resonance imaging (MRI). CT
scanning is an advanced imaging technique that uses x-rays and computer technology to
produces clear and detailed picture of the body area being examined. MRI scans produce
extremely detailed pictures of the inside of the body by using very powerful magnets and
computer technology. Other designations for other levels of the vertebrae include a) C1
through C7, where C stands for the cervical (neck) area; b) T1 through T12, where T
stands for the thoracic (chest) area, and c) S1 through S5, where S stands for the sacral
(sacrum) area. The lumbar vertebrae are located above the sacral vertebrae and below
the thoracic vertebrae.
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