Lumbar Vertebrae, Sacrum
and Coccyx
Chapter 8
Lumbar AP
Facility Identification
Correct Marker Placement
No Preventable Artifacts
Correct Film Size (14 x 17 lw)
Lumbar AP
Density
– Controlled by mAs
– Overall the density is not too dark or too light
Contrast
– Optimal kVp 75-85
– Bony trabecular patters and cortical outlines
are well visualized
– Vertebral bodies, pedicles, spinous processes,
laminae, and pars interarticulari are
demonstrated
Lumbar AP
True AP with no rotation
– The spinous processes are in the midline
of the vertebral body
– The distance from the spinous process
to each side of the vertebral body is
equal
– The sacrum and coccyx should be
centered within the inlet pelvis and
aligned with the symphysis
Lumbar AP
Detecting rotation
– If the spinous processes are closer to
one side of the vertebral body than the
other
– The side that the spinous process and
lateral border of the vertebral body
forms the greatest distance is the side
rotated toward
– Rotation can be either at the top
(shoulders) or bottom (hips) or both
Lumbar AP
The Intervertebral disk spaces are
open and the vertebral bodies are
demonstrated without distortion (flex
knees)
No foreshortening (hips or shoulders
higher than the other)
– The top and bottom of vertebral bodies
are demonstrated if foreshortening is
present
Lumbar AP
Align long axis of lumbar spine with
film
Center L-4-5 to center of film
Lumbar Posterior Oblique
Facility Identification
Correct Marker Placement
No Preventable Artifacts
Correct Film Size (14 x 17 lw or 11 x
14 lw)
Lumbar Posterior Oblique
Density
– Controlled by mAs
– Overall the density is not too dark or too light
Contrast
– Optimal kVp 75-85
– Bony trabecular patters and cortical outlines
are well visualized
– Vertebral bodies, pedicles, spinous processes,
laminae, and pars interarticulari are
demonstrated
Lumbar Posterior Oblique
Accurately rotated lumbar
– Scotty dogs are visualized
Ear – superior articular process
Eye – pedicle (near the center of the body)
Neck – pars interarticularis
Feet – inferior articular process
Body - lamina
Lumbar Posterior Oblique
Degree of obliquity
– Obliques too much
The “nose” of the Scotty dog is distorted
(too short) and zygapophseal joint is closed
– Not obliqued enough
The “eye” or pedicle of the Scotty dog
appears too close to the lateral border of the
spine
Lumbar Posterior Oblique
The long axis of the lumbar vertebral
column is aligned with the long axis
of the collimated field
The 3rd vertebra is in the center of
the collimated field with T12 and 1st
sacral segments visualized
Lumbar Lateral
Facility Identification
Correct Marker Placement
No Preventable Artifacts
Correct Film Size (14 x 17 lw)
Lumbar Lateral
Density
– Controlled by mAs
– Overall the density is not too dark or too light
Contrast
– Optimal kVp 75-85
– Bony trabecular patters and cortical outlines
are well visualized
– Vertebral bodies, pedicles, spinous processes,
laminae, and pars interarticulari are
demonstrated
Lumbar Lateral
The lumbar vertebra are
demonstrated in a true lateral
position
The intervetebral foramina are
clearly visualized
The spinous process are in profile
The right and left pedicles and the
posterior surfaces of each vertebral
body are superimposed
Lumbar Lateral
Detecting rotation
– Evaluate the superimposition of the
right and left posterior surfaces of the
vertebral bodies
Lumbar Lateral
To detect anterior or posterior
rotation
– Locate 12th rib
– Find magnified posterior rib
– If magnified rib is anterior the patient is
rotated then patient is rotated toward
the anterior surface toward the film
– If magnified rib is posterior the patient
is rotated then the posterior surface is
rotated closest to the film.
Lumbar Lateral
The intervetebral disk spaces are
open
Vertebral bodies are demonstrated
without distortion
– Align the vertebral column parallel to
the table top
Lumbar L5 – S1 Spot
Facility Identification
Correct Marker Placement
No Preventable Artifacts
Correct Film Size (8 x 10 lw)
Lumbar L5 – S1 Spot
Density
– Controlled by mAs
– Overall the density is not too dark or too
light
Contrast
– Optimal kVp 75-85
– Bony trabecular patters and cortical
outlines are well visualized
Lumbar L5 – S1 Spot
True positioning
– The 5th lumbar vertebra and sacrum are
visualized
– The intervetebral foramina are clearly
visualized
– Right and left pedicles are superimposed
– Greater sciatic notches and pelvic wings
are superimposed
Lumbar L5 – S1 Spot
Sacrum AP
Facility Identification
Correct Marker Placement
No Preventable Artifacts
Correct Film Size (10 x 12 lw)
Sacrum AP
The ischial spines are equally
demonstrated and are aligned with
the pelvic brim
Medial sacral crest and coccyx are
aligned with the symphysis
Sacrum AP
Detecting rotation
– Sacrum will rotate toward the side that
is up
– May also use pelvis criteria for detecting
rotation
Sacrum AP
The 1-5 sacral segments are not
foreshortened
– The sacral foramina are equally spaced
– The symphysis does not superimpose
any portion of the sacrum
Sacrum Lateral
Facility Identification
Correct Marker Placement
No Preventable Artifacts
Correct Film Size (10 x 12 lw)
Sacrum Lateral
Density
– Controlled by mAs
– Overall the density is not too dark or too
light
Contrast
– Optimal kVp 75-85
– Bony trabecular patters and cortical
outlines are well visualized
Sacrum Lateral
The median sacral crest is
demonstrated in profile
The greater sciatic and pelvic wings
are nearly superimposed
L5 – S1 disk space is open
Sacrum Lateral
The long axis of the sacrum is
aligned with the film
The 3rd sacral segment is in the
center of the film
Coccyx AP
Facility Identification
Correct Marker Placement
No Preventable Artifacts
Correct Film Size (8 x 10 lw)
Coccyx AP
Density
– Controlled by mAs
– Overall the density is not too dark or too
light
Contrast
– Optimal kVp 75-85
– Bony trabecular patters and cortical
outlines are well visualized
Coccyx AP
The coccyx is aligned with the
symphysis and is at equal distances
from the lateral walls of the pelvic
inlet
Coccyx AP
Detecting rotation
– The coccyx will move in the same
direction (toward) as the side that is up
Coccyx AP
The coccyx is in the center of the
film
The symphysis, pelvic brim and 5th
sacral segment are included on the
film
Coccyx Lateral
Facility Identification
Correct Marker Placement
No Preventable Artifacts
Correct Film Size (8 x 10 lw)
Coccyx Lateral
Density
– Controlled by mAs
– Overall the density is not too dark or too
light
Contrast
– Optimal kVp 75-85
– Bony trabecular patters and cortical
outlines are well visualized
Coccyx Lateral
The median sacral crest is
demonstrated in profile
The greater sciatic notches are
nearly superimposed
Coccyx lateral
Determining rotation
– It is most common for the patient to be
rotated anteriorly toward the table top if
they do not have a sponge between the
knees
Coccyx lateral
The first coccygeal vertebra is in the
center of the film
S5 – the third coccygeal vertebra on
film
Inferior median sacral crest are also
on film
THE END