erector pili muscle

erector pili (arrector pili) muscle

A tiny muscle capable of changing the angle of a hair follicle so as to cause hair to ‘stand on end’. Each follicle has one of these muscles which function under extremes of emotion.
References in periodicals archive ?
The etiology is unclear; speculation has centered on origin from the smooth muscle in the walls of blood vessels, in the erector pili muscles of hair follicles, or in aberrant undifferentiated mesenchyme.
3] This low incidence is attributed to the scarcity of smooth muscle in the head and neck, which is limited to erector pili muscles, vessel walls, and the esophagus.