A hinge assembly (10) for interconnecting a main body and a cover of a portable electronic device includes a hinge housing (20), and a first hinge apparatus (30) and a second hinge apparatus (40) rotatably contained in the housing and being perpendicular to each other. The first hinge apparatus includes a cam (36) rotatably attached to the housing and fixed to the main body, and other elements housed in the housing and fixed relative thereto. The second hinge apparatus includes a boom (43), a support (41) rotatably attached to the boom and fixed to the housing, and a pair of wings (433) extending from the boom and fixed to the cover. The cover is opened relative to the main body by being rotated about an X-axis of the first hinge apparatus. The cover is then rotated relative to the housing about a Y-axis of the second hinge apparatus.