In humans, the cerebral cortex is significantly larger than in other animals of similar size. Typically one to four millimeters thick with an approximate surface area of 2,000 square centimeters, the only way the sizable region of the brain can fit into the human skull is by folding extensively. The convolutions of the cerebral cortex are usually referred to in terms of sulci and gyri, which are respectively fissures and crests along the surface of the brain. The sulci and gyri exhibit patterns along the cerebral cortex and are the basis of the division of each hemisphere into six lobes. These lobes, which are usually identified as the frontal, parietal, temporal, occipital, central, and limbic lobes, are associated with various functions within the body.