The Four Children of Horus
In the pyramid texts we find a group of four gods with whom the deceased is closely connected in the “other world”; these are the four “children of Horus” whose names are given in the following order:–Hapi, Tua-mautef, Amset and Qebhsennuf. The deceased is called their “father.” His two arms were identified with Hapi and Tuamautef, and his two legs with Amset and Qebhsennuf; and when he entered into the Sekhet-Aaru they accompanied him as guides, and went in with him two on each side. They took away all hunger and thirst from him, they gave him life in heaven and protected it when given, and they brought to him from the Lake of Khemta the boat of the Eye of Khnemu. In one passage they are called the “four Khu‘s of Horus”, and originally they represented the four pillars which supported the sky or Horus. Each was supposed to be lord of one of the quarters of the world, and finally became the god of one of the cardinal points. Hapi represented the north, Tuamautef the east, Amset the south, and Qebhsennuf the west.
In the XVIIIth dynasty the Egyptians originated the custom of embalming the intestines of the body separately, and they placed them in four jars, each of which was devoted to the protection of one of the children of Horus, i.e., to the care of one of the gods of the four cardinal points. The god of the north protected the small visceræ, the god of the east the heart and lungs, the god of the south the stomach and large intestines, and the god of the west the liver and gall-bladder. With these four gods four goddesses were associated, viz., Nephthys, Neith, Isis, and Selk or Serq.
(Source: Egyptian Book of the Dead http://www.sacred-texts.com/egy/ebod/ebod09.htm)