Answer
In the anteroposterior (AP) view, the first (most superior) coccygeal vertebra can be distinguished from the other coccygeal vertebrae by the presence of the bilateral coccygeal cornu posteriorly and the bilateral transverse processes laterally. (The transverse processes of the first coccygeal segment are much wider and much more prominent than are the transverse processes of the inferior coccygeal vertebrae.)
The apex of the coccyx is usually rounded, but a bifid appearance can sometimes be appreciated in the AP radiographic view. The apex is typically midline but may deviate laterally.
Did this answer your question?
Additional feedback? (Optional)
Thank you for your feedback!
Media Gallery
-
Lateral view of the pelvis and coccyx. The bracket shows the area of focus for radiographs that would provide a coned-down view of mainly the coccyx and distal sacrum. A more common lateral view would often also include larger bony structures, such as the lumbar spine and femur, all of which would make it difficult to optimize visualization of the small bones of the coccyx. In patients with coccyx pain, these coned-down, lateral views of the coccyx can provide important diagnostic information. Coned-down images obtained in the weight-bearing (seated) position can be compared with those obtained in a non–weight-bearing position (eg, side lying), thus allowing assessment for dynamic instability (eg, dislocations that occur only while seated).
-
Coccyx pain (coccydynia, or tailbone pain) is typically worse when the patient is sitting. Often, the pain is even worse when sitting leaning slightly backward, since this increases the weight bearing on the coccyx, as shown in this image. Dynamic radiographs of the coccyx involve obtaining coned-down (focused) views of the coccyx while the patient is seated (eg, in his or her most painful position). Often, this involves having the patient lean backward 0-40°, depending on the symptoms. Radiographs obtained in this position are compared with those obtained in a non–weight-bearing position (eg, side lying) to assess for instability or dislocations in the seated position.
-
Patients with a painful coccyx often find it more comfortable to sit leaning slightly forward, as shown in this image. This forward-leaning position minimizes any weight bearing on the coccyx itself and thus minimizes the exacerbation of coccyx pain. As shown, when a patient sits leaning forward, most of the weight bearing occurs bilaterally through the inferior ischial regions of the pelvis and the posterior thigh (femur) regions.
of
3
