Axis (anatomy) The condition, where the dens is separated from the body of the axis, is called os odontoideum, and may cause nerve and circulation compression syndrome. On its anterior surface is an oval or nearly circular facet for articulation with that on the anterior arch of the atlas. On the back of the neck, and frequently extending on to its lateral surfaces, is a shallow groove for the transverse atlantal ligament which retains the process in position. The apex is pointed, and gives attachment to the apical odontoid ligament; below the apex the process is somewhat enlarged, and presents on either
Cold and heat adaptations in humans Stress from extreme external temperature can cause the human body to shut down. Hypothermia can set in when the core temperature drops to 35 °C (95 °F). Hyperthermia can set in when the core body temperature rises above 37.5-38.3 °C (99.5-100.9 °F). These temperatures commonly result in mortality. Humans have adapted to living in climates where hypothermia and hyperthermia are common primarily through culture and technology, such as the use of clothing and shelter. Modern humans emerged from Africa approximately 40,000 years ago during a period of unstable climate, leading to a variety of new traits among the population. Evidence