Sebaceous gland the hair shaft. The structure consisting of hair, hair follicle, arrector pili muscles, and sebaceous gland is an epidermal invagination known as a "pilosebaceous unit". Sebaceous glands are also found in hairless areas (glabrous skin) of the eyelids, nose, penis, labia minora, the inner mucosal membrane of the cheek, and nipples. Some sebaceous glands have unique names. Sebaceous glands on the lip and mucosa of the cheek, and on the genitalia, are known as Fordyce spots, and glands on the eyelids are known as meibomian glands. Sebaceous glands of the breast are also known as Montgomery's glands. Sebaceous glands are
Human head cartoons as having bigger heads as a way of notionally indicating that they have a "larger brain". Additionally, in science fiction, an extraterrestrial having a big head is often symbolic of high intelligence. Despite this depiction, advances in neurobiology have shown that the functional diversity of the brain means that a difference in overall brain size is only slightly to moderately correlated to differences in overall intelligence between two humans. The head is a source for many metaphors and metonymies in human language, including referring to things typically near the human head ( "the head of the bed"), things physically