An almond-shaped space between the lines of attachment of the labia minora. The clitoris is situated at the superior angle; the inferior boundary is the fourchette. The vestibule is approx. 4 to 5 cm long and 2 cm in greatest width when the labia minora are separated. Four major structures open into the vestibule: the urethra anteriorly, the vagina into the midportion, and the two secretory ducts of the glands of Bartholin laterally. The mucous membrane is stratified squamous epithelium.