Heart

Posterior view of the base of the heart (top); and posteroinferior view, i.e. the heart viewed from below and behind (bottom). The average adult heart is about the size of a clenched fist and weighs about eleven ounces; its shape approximates an upside-down pear.

© 2005 Netter Illustrations used with permission of Icon Learning Systems, a division of MediMedia USA, Inc. All rights reserved.