The eyebrow is an area of thick, delicate hairs above the eye that follows the shape of the lower margin of the brow ridges of some mammals. Their main function is to prevent sweat, water, and other debris from falling down into the eye socket, but they are also important to human communication and facial expression. It is not uncommon for people to modify their eyebrows by means of hair addition, removal and makeup.
#4 - Tragus
The tragus is a small pointed eminence of the external ear, situated in front of the concha, and projecting backward over the meatus.
#3 - Glabella
The glabella, in humans, is the skin between the eyebrows and above the nose. It also refers to the underlying bone which is slightly depressed, and joins the two superciliary ridges. It is a cephalometric landmark that is just superior to the nasion.
The skin of the glabella can be used to measure skin turgor in suspected cases of dehydrattion by gently pinching and lifting it. A dehydrated patient's glabella tends to remain extended rather than returning to its normal shape.
#2 - Plica Semilunaris
The plica semilunaris is a small fold of bulbar conjunctiva on the medial canthus of the eye. It functions during movement of the eye, to help maintain tear drainage via the lacrimal lake, and to permit greater rotation of the globe, for without the plica the conjunctiva would attach directly to the eyeball, restricting movement.
#1 - Uvula
The palatine uvula, usually referred to as simply the uvula is a conic projection from the posterior edge of the middle of the soft palate, composed of connective tissue containing a number of racemose glands, and some muscular fibers (musculus uvulae). It also contains a large number of serous glands that produce a lot of thin saliva.