For a long time, we did not realize that hair follicles grew as units rather than single strands. From a distance, hair follicles may appear to grow as singular strands, but actually, most individuals have follicular units with multiple hair follicles. Understanding the anatomy of the individual groups is essential to the safe dissection of the grafts with minimal damage or trauma to the hairs, as well as, the assurance of the production of natural three hair follicular groups. Natural follicular groups consisting of three or more hairs assist with the grafting and coverage of the top of the scalp and internal frontal areas.
Now, we will discuss the three different types of natural three hair follicular groups. Type one consists of three hairs lined up in a row. Type two contains two hairs exiting the same follicular canal, with one hair exiting lateral to this in a separate follicular canal, and type three consists of three hairs exiting from the same follicular canal. Dr. Cole named the third type a T-pee formation because it resembles an Indian's T-pee. These three types were discovered and named by John P. Cole, MD in 1998.
Follicular units not only contain these three hair follicular groups, but they also consist of nerves, blood vessels, and the erector pilorum muscle, all of which is surrounded by collagen. Removing the unit intact is essential to performing a successful hair transplant. Using follicular units allows for a more natural looking hair transplant. While the grafts must be placed in the proper path and dispersed accurately, this technique alone helps avoid the pluggy look.
A key benefit of using follicular units is that they keep the recipient sites as minute as possible and allow hair restoration surgeons to maximize the number of grafts transplanted per session. When using follicular units in hair restoration, the larger units are commonly used to cover the top of the head to add fullness, whereas, the smaller follicular units are used to create a natural hairline and temples.