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.
At the same time, if the person remains underwater, her body begins to accumulate carbon dioxide. This gas is what stimulates you to feel that need to breathe. Eventually, the victim involuntarily draws in breath. When water reaches the airway, the first response is to cough or swallow the water.