Air embolism and veins is greater than atmospheric pressure, an air embolus does not often happen when a blood vessel is injured. In the veins above the heart, such as in the head and neck, the venous pressure may be less than atmospheric and an injury may let air in. This is one reason why surgeons must be particularly careful when operating on the brain, and why the head of the bed is tilted down when inserting or removing a central venous catheter from the jugular or subclavian veins. When air enters the veins, it travels to the right side of the
American Academy of Otolaryngology–Head and Neck Surgery before adding "Head and Neck Surgery" to its name, yielding the American Academy of Otolaryngology–Head and Neck Surgery in 1980. In 1981, the American Council of Otolaryngology (ACO), which had formed in the 1960s for purposes outside the scope of the original educational organization (such as lobbying), merged with the American Academy of Otolaryngology–Head and Neck Surgery. American Academy of Otolaryngology–Head and Neck Surgery The American Academy of Otolaryngology–Head and Neck Surgery (AAO-HNS) is one of the largest of the world's many professional associations for medical specialists, with nearly 12,000 specialists in the area of otolaryngology (otorhinolaryngology) - caring for