o_19gutb9tvriojp4s1o13fc1mena.pdf

yoga and the spine 21
Vertebral Structure
From the top of the cervical spine to the base
of the lumbar spine, individual vertebrae are
dramatically different in shape based on the
functional demands of the varying regions of
the spine (figure 2.10). There are, however,
common elements to all vertebral structure,
as illustrated by the schematic representation
in figure 2.11.
Weight-bearing activities in general, as well
as axial rotation (twisting movements), produce
symmetrical (axial) compressive forces that flatten
the nucleus into the annulus, which pushes
back, resulting in a decompressive reaction (see
figure 2.12). If the compressive force is high
enough, rather than rupture, the nucleus will
lose some of its moisture to the porous bone of
the vertebral body. When the weight is taken
Figure 2.9 The nucleus pulposus is tightly
bound by the annulus fibrosis, which contains
concentric rings of oblique fibers that
alternate their direction—similar to the
internal and external abdominal obliques.
off the spine, the hydrophilic nucleus draws the water back in, and the disc returns to its
original thickness. That is why humans are a bit taller right after getting out of bed.
C1
T10
C2
C3
T12
C7
L1
T1
L5
Figure 2.10 The changing shape of the vertebrae.