Sekhmet was the fierce goddess of the Memphite area, forming a powerful trio with her husband, the creator-god Ptah, and their son, Nerfertum. Sekhmet was goddess of the sun and war: she symbolised the scorching heat of the sun, and brought plague and pestilence. She was seen as the fiercest of warriors, and was the protector of the pharaohs. It was said that the desert was caused by her breath alone, and she was rendered as a lion because this big cat was the bravest hunter known to the Egyptians. Perhaps this amulet, therefore, was used to evoke power and strength.
To find out more about Ancient Egyptian amulets please see our relevant blog post: Egyptian Amulets and their Meanings: Ancient Egyptian Gods.