Note the calcification present lateral to the facet structure at the C3/4 and C4/5 levels. This is consistent with conduit vessel calcification and in this location, is related to advanced atherosclerosis in the carotid arteries. Atherosclerosis of the carotid artery often occurs at its bifurcation (bulb) at the C4 to C5 level. This degree of atherosclerosis is quite severe. It is best seen on the AP lower cervical spine radiograph but occasionally it could be seen anterior to the vertebral bodies at the C4 level on the lateral film. This type of atherosclerotic calcification is “hard” plaquing which is visualized on radiography but there can also be “soft” plaquing which cannot be seen without further imaging. This can narrow the artery even further and both can lead to reduced blood flow to the brain stem. Patient’s with atherosclerosis of the carotid arteries should have a diagnostic ultrasound to determine the degree of stenosis of the patient’s blood flow. If the reduction of blood flow reaches approximately 70% or above most vascular surgeons would consider surgical intervention to reduce the plaque. The usual surgical procedure performed is an endarterectomy removing the plaque which is usually quite successful in restoring adequate blood flow. This degree of atherosclerotic plaque within the carotids can predispose the patient to a possible stroke. High-velocity, low-amplitude manipulation in a patient with this degree of atherosclerosis is not recommended, particularly before ultrasound is performed. Any extension rotation manipulation of an area with this degree of atherosclerosis should be avoided. If cervical manipulation is performed, it should be done in the supine, flexed position