Fundus is a term used to describe the interior surface of an organ, usually the stomach or uterus. It can also refer to the bottom of a structure, such as the eye or the heart. The fundus of the stomach is the uppermost portion of the organ. It is the area where food and liquid are stored before being pushed further down the digestive tract. The fundus is a muscular organ made up of four layers: mucosa, submucosa, muscularis, and serosa. The fundus of the uterus is the area located at the top of the organ. It is important for maintaining a pregnancy and helps to keep the developing fetus in place. It is also the area where the placenta attaches to the uterus. The fundus is made up of two layers: the endometrium and the myometrium. The fundus of the eye is located at the bottom of the eyeball. It is made up of three layers: the choroid, the retina, and the sclera. The fundus helps to provide nourishment to the retina, which is responsible for sensing light and sending visual signals to the brain.