Endoscopic image of the human foetus in vivo, after 8 weeks, showing the face in profile: The large dark spot (right) is the retina of the eye (the eyes are widely spaced at this time), while on the left are the basic structures of the nose and mouth. The endoscope, a series of lenses and a fibre-optic light source, is inserted through the cervix (the neck of the womb) and manipulated until a "window" into the amniotic sac is found (ie an area where the wall is thinner).