Variations of Hair Follicle Size and Distribution in Different Body Sites

The study evaluated hair follicle characteristics across seven body sites and found significant variations. The forehead had the highest hair follicle density and follicular orifices, while the calf region had the largest follicular orifices. Both the forehead and calf had the highest infundibular volumes, suggesting a substantial follicular reservoir, comparable to the stratum corneum. The forearm had the lowest values for all parameters. These findings challenged previous beliefs about skin appendage distribution and highlighted the need for region-specific approaches in studying skin penetration of topical treatments.