What is the ruling on a woman wearing short sleeves that expose the elbow, and what is the legal standard for this, especially in front of mahrams?

A woman is permitted to show her head, forearms, and feet in front of her mahram relatives and other women. It is understood from this that it is permissible to show the elbow. However, if a dress is so short that it reveals the upper arm or the side, it is not permissible to wear it in front of mahram relatives.