Bulb of vestibule

The bulb of the vestibule (bulbus vestibuli; vaginal bulb) is the homologue of the bulb of penis and adjoining part of the corpus cavernosum urethræ of the male, and consists of two elongated masses of erectile tissue, placed one on either side of the vaginal orifice and united to each other in front by a narrow median band termed the commissure of bulbs of vestibule (pars intermedia). 

Each lateral mass measures a little over 2.5 cm in length. Their posterior ends are expanded and are in contact with the greater vestibular glands; their anterior ends are tapered and joined to one another by the commissure of bulbs of vestibule (pars intermedia).; their deep surfaces are in contact with the inferior fascia of the urogenital diaphragm; superficially they are covered by the bulbospongious muscle.