Can someone explain why transplanted hair in the crown grows slower?

[PeloDinero]

I've heard this rule many times and seen plenty of anecdotal data to support it (including myself as I'm 6 months out and still have lots of hairs just now poking through) but I don't have a good grasp as why, physiologically, this is true. I've heard it's because blood flow to the crown is less but is this really true? Any other scientific reasons why crown hair grows in slower compared to hairline hair? Any feedback from the surgeons on the board would be greatly appreciated too. Thanks!

[Speegs]

I think it's two fold in that blood supply is not as ample in the crown as it is in the hairline region and the illusion of density is a more difficult task in the crown than in the frontal scalp, it often takes a great deal of grafts to create a density that can match the rest of the scalp.

 

Crown hair transplantation is a skill unto itself, not everyone does it well.

[gillenator]

I have also heard of the blood supply issue but don't know if I totally agree with it. To date, it's a phenomenon that is still a mystery IMHO...:rolleyes:

[mattj]

Blood supply is as good a reason as any I've heard, but I think it is definitely one of those mysteries.