Aspiration means the withdrawal of ﬂuid or gases from the natural cavities of the body or from cavities produced by disease. It may be performed for curative purposes; alternatively, a small amount of ﬂuid may be drawn oﬀ for diagnosis of its nature or origin. An instrument called an aspirator is used to remove blood and ﬂuid from a surgical-operation site – for example, the abdomen or the mouth (in dentistry).
PLEURISY with eﬀusion is a condition requiring aspiration, and a litre or more of ﬂuid may be drawn oﬀ by an aspirator or a large syringe and needle. Chronic abscesses and tuberculous joints may call for its use, the operation being done with a small syringe and hollow needle. PERICARDITIS with eﬀusion is another condition in which aspiration is sometimes performed. The spinal canal is aspirated by the operation of LUMBAR PUNCTURE. In children the ventricles of the brain are sometimes similarly relieved from excess of ﬂuid by piercing the fontanelle (soft spot) on the infant’s head. (See HYDROCEPHALUS.)