The normal adult spleen lies immediately under the diaphragm in the left upper quadrant of the abdomen. It ranges in length from 6 to 13 cm and in weight from 75 to 120 g. The spleen is not normally palpable except in slender young adults. When the spleen can be felt below the left costal margin, at rest or on inspiration, splenic enlargement should be assumed and the explanation sought. Although the normal-size, or even the abnormally small, spleen can be involved in pathologic processes, with the exception of rubs associated with splenic infarcts, physical examination is generally not helpful in identifying the problem. Nevertheless, the enlarged and palpable spleen is an important clue to the presence of a variety of illnesses.
