220
UNIT TWO
Cervical Vertebrae
Seven
cervical vertebrae
comprise the bony axis of the
neck. These are the smallest of the vertebrae, but their bone
tissues are denser than those in any other region of the ver-
tebral column.
The transverse processes of the cervical vertebrae are
distinctive because they have
transverse foramina,
pas-
sageways for arteries leading to the brain. Also, the spinous
processes of the second through the sixth cervical vertebrae
are uniquely forked (biF
d). These processes provide attach-
ments for muscles.
The spinous process of the seventh vertebra is longer
and protrudes beyond the other cervical spines. It is called
the
vertebra prominens,
and because it can be felt through
the skin, it is a useful landmark for locating other vertebral
parts (see F
g. 7.32).
roughened upper and lower surfaces of the vertebral bodies.
These discs cushion and soften the forces caused by such
movements as walking and jumping, which might otherwise
fracture vertebrae or jar the brain. The bodies of adjacent
vertebrae are joined on their anterior surfaces by
anterior
longitudinal ligaments
and on their posterior surfaces by
posterior longitudinal ligaments.
Projecting posteriorly from each vertebral body are two
short stalks called
pedicles
(ped
ı˘-k
lz). They form the sides of
the
vertebral foramen.
Two plates called
laminae
(lam
ı˘-ne)
arise from the pedicles and fuse in the back to become a
spinous process.
The pedicles, laminae, and spinous process
together complete a bony
vertebral arch
around the vertebral
foramen, through which the spinal cord passes.
Between the pedicles and laminae of a typical vertebra
is a
transverse process,
which projects laterally and posteri-
orly. Various ligaments and muscles are attached to the dor-
sal spinous process and the transverse processes. Projecting
upward and downward from each vertebral arch are
superior
and
inferior articulating processes.
These processes bear car-
tilage-covered facets by which each vertebra is joined to the
one above and the one below.
On the lower surfaces of the vertebral pedicles are
notches that align with adjacent vertebrae to help form
openings called
intervertebral foramina
(in
ter-ver
te˘-bral
fo-ram
ı˘-nah). These openings provide passageways for spi-
nal nerves.
Body
Superior
articular
process
Spinous
process
Transverse
process
Inferior articular
process
Intervertebral
disc
Anterior
Posterior
Body
Pedicle
Vertebral foramen
Superior articular process
Facet for tubercle of rib
Transverse process
Lamina
Spinous process
Inferior articular
process
Intervertebral notch
Body
Pedicle
Superior
articular
process
Transverse
process
Facet for
tubercle of rib
Spinous
process
(a)
(c)
(b)
FIGURE 7.33
Typical thoracic vertebra. (
a
) Right lateral view. (
b
) Adjacent vertebrae join at their articular processes. (
c
) Superior view.
Gymnasts, high jumpers, pole vaulters, and other athletes who
hyperextend and rotate their vertebral columns and stress them with
impact sometimes fracture the portion of the vertebra between the
superior and inferior articulating processes (the pars interarticularis).
Such damage to the vertebra is called spondylolysis, and it is most
common at L5.
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