[434] And how does a bhikkhu dwell contemplating the body in the body (kāyānupassī) internally and externally (ajjhattabahiddhā)?
Here a bhikkhu reviews the body internally and externally — upward from the soles of the feet, downward from the tips of the head-hair, enclosed by skin, as full of many kinds of impurity: "There are in the body head-hairs, body-hairs, nails, teeth, skin, flesh, sinews, bones, bone-marrow, kidneys, heart, liver, pleura, spleen, lungs, intestines, mesentery, contents of the stomach, feces, bile, phlegm, pus, blood, sweat, fat, tears, grease, saliva, snot, synovial fluid, and urine."
Thus a bhikkhu dwells contemplating the body in the body internally and externally, ardent (ātāpī), clearly comprehending (sampajāno), and mindful (satimā), having removed covetousness and grief regarding the world (abhijjhā-domanassa).
English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.