[alt def] The hollow thick-walled muscular organ in the female pelvis. It consists of the fundus (the body) which is the site of embryo implantation and fetal development. Beyond the isthmus at the perineal end of fundus, is cervix uteri (the neck) opening into vagina. Beyond the isthmi at the upper abdominal end of fundus, are the fallopian tubes. [MeSH]