The human foetus at about the 4th month of development, showing the head & upper limbs & the umbilical cord which connects the foetus (at the navel) to the placenta, a large organ embedded in the uterine wall that interfaces the foetal & maternal circulations, exchanging nourishment & waste products. Growth at this time is rapid: the head is still relatively large with a bulging forehead, the outer ear is formed, as are the nose & mouth; the eyes have migrated from the sides of the head, although the eyelids have not yet fully developed. Forearms, wrists, hands & fingers are well differentiated, developing at a faster rate than the lower limbs.