Prayer is invalidated by exposing a large part of the private parts, which is estimated at a quarter; thus, a quarter of the member and above is considered a lot, whether it is from the major private parts: which are the front and the back, or from the minor private parts: which are anything other than the front and the back. The head is a member, and the falling hair is another member, the male organ is one member, and the female organs are another member, and each of the woman's ears is a member on its own, and her breast in the case of fullness is considered part of the chest, and when it grows, it is considered a member on its own. The knee with the thigh is a member according to what is preferred, and the woman's ankle with her leg is a member, and what is between a man's navel and his pubis around the entire body is a member on its own, the abdomen is a member, the thigh is a member, and the leg is a member. If a quarter of any of these members is uncovered, it prevents the validity of the prayer; if it is less than a quarter, it is considered little and does not prevent the validity of the prayer due to necessity, as clothing usually has a little tear. The scattered exposure of the private parts is gathered like scattered impurity; if a sixth of her hair is uncovered, a sixth of her abdomen, and a sixth of her thigh, they are gathered, and if it reaches a quarter of any of these members, it becomes a barrier; otherwise, it does not. Refer to: Maraqi al-Falah p. 210-211, Al-Wiqayah and its explanation by Sadr al-Shari'ah 1: 143, Radd al-Muhtar 1: 408, Badā'i al-Sanā'i 1: 117, and Al-Hadiyyah al-'Alaiyyah p. 72.