Axillary fossa1, to be specific. A grand name for a body part that doesn’t ordinarily get a lot of love: a.k.a. “the armpit”.
This is a detail from a photo I posted recently. I like how, when taken out of context, it starts to look like wind-sculpted rock.
(Sinful Sunday is a weekly meme featuring sensual and erotic photography. Click the icon at the top of this post to go to the homepage and check out the other links.)