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Updated: Apr 24, 2026

A New Technique for Quantitative Analysis of Hair Loss in Mice Using Grayscale Analysis
Published on: March 9, 2015
Beyond goosebumps: does the arrector pili muscle have a role in hair loss?
Niloufar Torkamani1, Nicholas W Rufaut1, Leslie Jones1
1University of Melbourne, Melbourne, Victoria, Australia ; Epworth Hospital, Melbourne, Victoria, Australia.
Abstract:
The arrector pili muscle (APM) consists of a small band of smooth muscle that connects the hair follicle to the connective tissue of the basement membrane. The APM mediates thermoregulation by contracting to increase air-trapping, but was thought to be vestigial in humans. The APM attaches proximally to the hair follicle at the bulge, a known stem cell niche. Recent studies have been directed toward this muscle's possible role in maintaining the follicular integrity and stability. This review summarizes APM anatomy and physiology and then discusses the relationship between the follicular unit and the APM. The potential role of the APM in hair loss disorders is also described, and a model explaining APM changes in hair loss is proposed.
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