Carotid artery dissection dissection is thought to be more commonly caused by severe violent trauma to the head and/or neck. An estimated 0.67% of patients admitted to the hospital after major motor vehicle accidents were found to have blunt carotid injury, including intimal dissections, pseudoaneurysms, thromboses, or fistulas. Of these, 76% had intimal dissections, pseudoaneurysms, or a combination of the two. The probable mechanism of injury for most internal carotid injuries is rapid deceleration, with resultant hyperextension and rotation of the neck, which stretches the internal carotid artery over the upper cervical vertebrae, producing an intimal tear. After such an injury, the patient
Composition of the human body viewed on an atomic and molecular scale as shown in this article. The estimated gross molecular contents of a typical 20-micrometre human cell is as follows: Body composition can also be expressed in terms of various types of material, such as: There are many species of bacteria and other microorganisms that live on or inside the healthy human body. In fact, 90% of the cells in (or on) a human body are microbes, by number (much less by mass or volume). Some of these symbionts are necessary for our health. Those that neither help nor harm humans are called commensal