Show June 19, 2003 -- This article is the 15th in our series of white papers on radiologic patient positioning techniques for x-ray examinations. If you'd like to comment on or contribute to this series, please e-mail .The standard radiographic examination for evaluating the lumbar spine includes the anteroposterior, lateral, and oblique projections, supplemented by coned-down lateral films of the lumbosacral junction (L5-S1). The anteroposterior (AP) view is usually sufficient for evaluating traumatic conditions involving vertebral bodies and transverse processes, and the intervertebral disk spaces are also well demonstrated, except for the lowest (L5-S1). The spinous processes and articular facets however are not well demonstrated on this projection. On the lateral projection of the lumbar spine, the vertebral bodies are seen in profile and the superior and inferior end plates are well demonstrated. Fractures of spinous processes are adequately evaluated on this projection, as are abnormalities involving the intervertebral disc spaces, including L5-S1. Oblique views are particularly effective in demonstrating the facet joints (articular facets). Examination of motion in the lumbar spine may provide useful information. To accomplish this, lateral radiographs may be obtained during flexion and extension, and frontal radiographs may be obtained during lateral bending of the spine. AP (or PA) projection of the lumbar-lumbosacral spine The frontal radiograph of the lumbar spine can be obtained in the posteroanterior (PA) or AP projection with the patient erect or recumbent. Although the AP projection is more commonly used, there are some advantages to the PA projection. Because the patient is in a prone position in the PA projection, the natural lumbar curvature is placed in such a way that the intervertebral disk spaces are parallel to the diverging beam of radiation, thus allowing better visualization of the intervertebral disc spaces. Moreover, the PA projection is more comfortable for patients who have back pain. An additional advantage is lower radiation dose for females (25%-30% less for a PA projection compared with AP projection). A disadvantage of the PA projection for a patient with a large abdomen is the increased object to image distance (OID) of the lumbar vertebra, which results in radiographic distortion. Technical factors
Positioning for the AP projection of the lumbar-lumbosacral spine
Evaluation criteria
Lateral projection of the lumbar-lumbosacral spine Technical factors
Positioning for lateral projection of the lumbar-lumbosacral spine
Evaluation criteria
Oblique projection of the lumbar-lumbosacral spine As in the cervical spine, an oblique projection of the lumbar spine can be obtained from either the patient’s anterior or posterior aspect, although the PA oblique projection is preferable. Oblique radiographs allow evaluation of the posterior elements of the lumbar spine (lamina, pedicle, the facet joints, and intervertebral foramina) although some regard the oblique projections as unnecessary. The L5 intervertebral foramina (right and left) are not usually well visualized on the lateral projection because of their oblique direction. Consequently, oblique projections are used for these foramina. When oblique projections are indicated, they are generally performed after the AP projection and in the same body position (recumbent or upright). For comparison, radiographs are generally obtained from both sides (right and left oblique). Technical factors
Positioning for oblique projections of the lumbar-lumbosacral spine
Evaluation criteria
AuntMinnie.com contributing writer June 19, 2003 Related Reading Radiographic positioning techniques for the cervical spine, March 26, 2003 Boning up on humerus, clavicle, and AC joint positioning, February 18, 2003 Getting the most from shoulder positioning, December 24, 2002 The bends and flexures of forearm and elbow x-ray positioning, November 21, 2002 The twists and turns of hand and wrist x-ray positioning, October 15, 2002 Copyright © 2003 AuntMinnie.com Which position of the lumbar spine best demonstrates the zygapophyseal joints?The left posterior oblique position of the lumbar spine best demonstrates the zygapophyseal joints.
Where is the zygapophyseal joint located?Applied anatomy
Zygapophyseal joints are the only synovial joints in the spine, with hyaline cartilage overlying subchondral bone, a synovial membrane and a joint capsule; they comprise the postero-lateral articulation between vertebral levels (Figure 1).
What projection shows cervical zygapophyseal joints?Accurate radiographic demonstration of these foramina requires a 15-degree longitudinal angulation of the central ray and a 45-degree medial rotation of the patient (or a 45-degree medial angulation of the central ray). A lateral projection is necessary to show the cervical zygapophyseal joints.
Which of the following projections will best demonstrate the zygapophyseal joints of the cervical spine?The PA projection (Judd method) is intended to demonstrate the zygapophyseal joint between C1 and C2. The posterior cervical oblique projections demonstrate the intervertebral foramina and pedicles on the side closest to the image receptor.
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