But in some you don’t see this at all.
Actually, this tendon, is a small muscle known as the Palmaris longus muscle. This is present as an vestigial organ in the middle of the wrist. But as always, this does not have a purpose at all.
In fact it is now present in just 10-15% of the population. So besides being an attraction, this tendon has no use at all. If you have this tendon present you are among the gene pool which has this trait. Rest are members of the evolution club! But an honest opinion, it does look cool, sadly I don’t have it. LOL