BACKGROUND: There is general agreement that the proximal attachment site of the arrector pili (AP) muscle, via elastic tendons, is the bulge region, where follicular stem cells are situated. A variant of this insertion, in which the AP muscle surrounds the follicle circumference, has been described in human facial vellus hair follicles. OBJECTIVES: To investigate whether terminal hair follicles of the human scalp may also present this variant of proximal insertion of the AP muscle. METHODS: Histological and immunohistochemical methods were used. RESULTS: At the bulge level, bundles of the AP muscle were seen to encircle the entire hair follicle. CONCLUSIONS: Terminal follicles of the human scalp may also present this variant of proximal insertion of the AP muscle.
BACKGROUND: There is general agreement that the proximal attachment site of the arrector pili (AP) muscle, via elastic tendons, is the bulge region, where follicular stem cells are situated. A variant of this insertion, in which the AP muscle surrounds the follicle circumference, has been described in humanfacial vellus hair follicles. OBJECTIVES: To investigate whether terminal hair follicles of the humanscalp may also present this variant of proximal insertion of the AP muscle. METHODS: Histological and immunohistochemical methods were used. RESULTS: At the bulge level, bundles of the AP muscle were seen to encircle the entire hair follicle. CONCLUSIONS: Terminal follicles of the humanscalp may also present this variant of proximal insertion of the AP muscle.
Authors: Hironobu Fujiwara; Manuela Ferreira; Giacomo Donati; Denise K Marciano; James M Linton; Yuya Sato; Andrea Hartner; Kiyotoshi Sekiguchi; Louis F Reichardt; Fiona M Watt Journal: Cell Date: 2011-02-18 Impact factor: 41.582