The most significant structural properties of the skin of the brows and glabella are (a) one half or more of the follicles produce vellus hairs; (b) all follicles are so richly vascularized and innervated that they are comparable to the vibrissae follicles of nonhuman primates; (c) many acetylcholinesterase-positive nerves penetrate the epidermis, pilary canal, and perhaps the outer root sheath of follicles; (d) the follicles in the brows, but not in the glabella are free of arrectores pilorum muscles; (e) eccrine sweat glands are few or absent; (f) the dermis, like that of the skin anywhere on the head normally contains great quantities of elastic tissue, even in the young.