l-spine

routine frontal lumbar spine images are typically performed with the patient in which of the following positions?
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routine frontal lumbar spine images are typically performed with the patient in which of the following positions?
Supine on table with knees flexed
Typically, for a frontal image of the lumbar spine the patient is positioned supine on the table. The knees are flexed for this procedure. Erect imaging of the spine may be used for certain orthopedic procedures to determine the effect of gravity on the spine.
Which of the following would be benefits of flexing the knees when performing an AP lumbosacral spine x-ray?
1. Flexing the knees straightens the curve of the spine and places it closer to the image receptor (IR)
2. Flexing the knees results in more consistent brightness levels across the length of the spine
3. Flexing the knees makes the patient more comfortable reducing the chance of motion
1 and 3
The lumbar spine has a natural convex curve, which can cause shape distortion of the vertebrae. Bending the knees straightens this curve bringing the spine more parallel with the IR, and also places the spine closer to the image receptor, reducing magnification that might occur due to the distance between the spine and the receptor. This position is also more comfortable for the patient, so it is easier to maintain and there is a reduced chance of motion.
Why is the lateral lumbar spine radiograph taken with the patient holding the breath in expiration?
it reduces the superimposition of the costophrenic angles and the first lumbar vertebra.
Suspended respiration is required to prevent motion on the image, and the preference is for suspended expiration. Expiration will elevate the diaphragm, eliminating superimposition of the costophrenic angles and the 1st lumbar vertebra. Suspended inspiration could result in the upper vertebrae lying within lung shadows, creating a much darker shade of gray for those structures.
When performing a right posterior oblique (RPO) lumbar spine radiograph, the body should be rotated so that the mid-sagittal plane (MSP) forms what degree of angulation with the image receptor (IR)?
45 degrees
Oblique lumbar spine images are typically obtained in order to evaluate the zygapophyseal joints. These joints are oriented at a 45 degree angle to the MSP. Optimal positioning is demonstrated when the vertebrae have the appearance of a "scotty dog".
Where should the central ray enter for a right posterior oblique (RPO) of the lumbosacral spine?
2 inches medial to the left ASIS and 1.5 inches superior to the level of the iliac crest
Centering at the iliac crest ensures the entire lumbosacral spine is included on the radiograph. In order for the central ray to pass through the spine, the central ray should enter approximately 2 inches medial to the elevated (left) ASIS and 1.5" superior to the iliac crest.
When performing a lateral lumbar spine on a patient with a wide pelvis and a narrow waist, which of the following should be done?
A sponge should be placed under the waist to ensure the entire spine is parallel to the image receptor.
When patients have wide hips and narrow waists the lumbar spine tends to sag at the waist, resulting in shape distortion of the vertebrae. In order to prevent this sagging and to place the spine parallel with the image receptor, a sponge should be placed under the patient's waist.
Which of the following statements is TRUE regarding positioning for a lateral lumbar spine?
The central ray enters at the midcoronal plane
Correct centering for a lateral lumbosacral spine should demonstrate the central ray entering the midcoronal plane at the level of the iliac crest. If the lateral is for demonstration of the lumbar spine only, the central ray will enter the midcoronal plane approximately 1.5 inches superior to the level of the iliac crests.
What is the correct central ray orientation for a localized lateral of the L5/S1 vertebrae?
5-8 degrees caudad
Most patients are built so that the hips are wider than the shoulders, so angling the central ray 5-8 degrees caudad compensates for the natural angle created by the width of a patient's hips. Five degrees is typically recommended for a male patient, and eight degrees is recommended for a female patient. The angle may vary depending on the width of the patient's hips and the angle at the L5-S1 joint.
When radiographing the lumbar spine in the oblique position, the vertebral anatomy resembles a "scotty dog". The eye of the scotty dog represents which of the following?
Pedicle
The oblique lumbar spine anatomy typically has the appearance of a "scotty dog" when the patient is positioned correctly. The eye of the dog corresponds to the pedicle of the vertebra; the ear corresponds to the superior articular process; the front leg corresponds to the inferior articular process; the nose corresponds to the transverse process; the neck corresponds to the pars interarticularis.
Which of the following conditions would be indicated by the appearance of a collar on the scotty dog on an oblique lumbar spine radiograph?
Spondylolysis
Spondylolysis is a condition in which there is a cleft in the pars interarticularis of a lumbar or cervical vertebra. The pars interarticularis corresponds to the neck of the scotty dog. A cleft or fracture is represented as a lucent line through the pars interarticularis.
Which of the following represents correct evaluation criteria for an AP lumbosacral spine radiograph? 1. The pedicles are equidistant to the spinous processes 2. Spinous processes are centered to the vertebral bodies 3. The vertebral laminae are superimposed1 and 2 When evaluating an AP lumbar spine radiograph, rotation can be determined by the appearance of the spinous processes and the pedicles. The spinous processes should be centered to the vertebral bodies and the pedicles should be equidistant to the spinous processes. When the knees are bent, the spine will be parallel to the image receptor and the intervertebral joint spaces clearly seen.The outer portion of an intervertebral disk the:Annulus fibrosus Vertebral bodies are separated from each other by intervertebral disks. The central portion of each disk, or nucleus pulposus, is soft and spongy. The outer portion of each disk is denser, composed of fibrocartilage and is referred to as the annulus fibrosus.For the lateral projection of the L5-S1 joint, the central ray is directed:1 to 1 ½ inches inferior to the iliac crest and 2 inches posterior to the ASIS. The joint space between the 5th lumbar vertebra and the sacrum is a common site for pathology, especially spondylolisthesis. This is a condition where one vertebra slips anteriorly in relation to the vertebral body below. To properly demonstrate the L5/S1 joint space, the central ray should enter the patient approximately 2 inches posterior to the ASIS and 1 ½ inches inferior to the iliac crest.On this image of the lumbar spine, letter A refers to the:Intervertebral foramen Letter A is pointing to the intervertebral foramen between L2 and L3. Intervertebral foramina are formed by the inferior pedicle borders of one vertebra and the superior borders of the pedicle of the vertebra below. These openings permit transmission of spinal nerves and vascular structures.On this image of the lumbar spine, letter D refers to the:Pedicle On this lateral image of the lumbar spine, letter A is pointing to the intervertebral foramen between L2 and L3; letter B is the spinous process of L2, letter C is pointing to the superimposed laminae of L3, and letter D is pointing to the superimposed pedicles of L4.