lumbar vertebrae the five vertebrae between the thoracic vertebrae and the sacrum. vertebra magÂ´na the sacrum. odontoid vertebra the second cervical vertebra, or axis. vertebra plaÂ´na a condition of spondylitis in which the body of the vertebra is reduced to a sclerotic disk.
Generally, in the early stages of drowning, very little water enters the lungs: a small amount of water entering the trachea causes a muscular spasm that seals the airway and prevents the passage of both air and water until unconsciousness occurs.
Chokes is due to movement of many nitrogen bubbles from the venous system to the lungs. Although a small number of bubbles will be trapped and exhaled, a large number can overwhelm the lung circulation, and lead to respiratory distress. Symptoms can occur up to 12 hours after the dive and may persist for 12-48 hours.