The Procerus is a small pyramidal slip of muscle deep to the superior orbital nerve, artery and vein. It helps to pull that part of the skin between the eyebrows downwards, which assists in flaring the nostrils. It can also contribute to an expression of anger. Procerus is supplied by temporal and lower zygomatic branches from the facial nerve (a supply from the buccal branch has been described). Its contraction can produce transverse wrinkles.