Brunette Girl With Huge Breasts Wearing A White Underwear

The end of the breast, which includes the nipple, may either be flat (a 180° angle) or angled (angles lower than 180°). Breast ends are rarely angled sharper than 60°. Angling of the end of the breast is caused in part by the ligaments that suspend it, such that the breast ends often have a more obtuse angle when a woman is lying on her back. Breasts exist in a range of ratios between length and base diameter, usually ranging from ½ to 1.
Development
Girls develop breasts during puberty, as a result of changing sex hormones, chiefly estrogen, which also has been demonstrated to cause the development of woman-like, enlarged breasts in men, a condition called gynecomastia.