bulbospongiosus muscle


bul·bo·spon·gi·o·sus mus·cle

(bŭl'bō-spŏn-jē-ō'sŭs mŭs'ĕl) Perineal muscle; in male: origin, perineal membrane fascia on the dorsum of bulb of penis; insertion, central tendon of perineum and median raphe on free surface of the bulb; action, voluntarily constricts bulbous urethra when attempting to expel last drops after urination, or spasmodically with, and following, ejaculation to expel semen. In female: origin, dorsum of the clitoris, the corpus cavernosum, and the perineal membrane; insertion, central tendon of the perineum; action, acts as a weak sphincter of the vagina; nerve supply, pudendal (deep perineal branch).
Synonym(s): bulbocavernosus muscle, musculus bulbocavernosus, musculus bulbospongiosus, musculus ejaculator seminis, musculus sphincter vaginae, sphincter vaginae.