Now that we've seen the internal aspects of the female reproductive system, we'll move on to look at the external genital structures.
The female genital and urinary openings are concealed, and protected by the labia majora, which we're seeing here from directly below. To see more, we'll separate the labia majora, and hold them apart with sutures. Between the labia majora are these two smaller folds, the labia minora.
Concealed just in front of the point where the labia minora meet is the head of the clitoris, which is the female analog of the penis. We'll see more of it shortly.
The labia minora surround the entrance to this space, the vestibule of the vagina. In front, the urethra opens into the vestibule at the external urethral meatus. Opening into the vestibule from above, is the vagina.
To see the erectile and muscular structures of the female perineum we'll look at a dissection in which all the skin and subcutaneous fat of the perineum have been removed.
The ischio-pubic rami are here, the ischial tuberosities are here. The pubic symphysis is here. Here are the dry bones seen from the same angle, with the pubic symphysis, the ischial tuberosities, and the ischio-pubic rami.
On each side the adductor muscles of the thigh, arise from the edges of the ischio-pubic rami. Here are the edges of the labia minora.
Within each of the labia minora there's a thin almost tubular sheet of muscle, the bulbo-spongiousus muscle. The most posterior fibers of bulbo-spongiosus meet with the most anterior fibers of the external anal sphincter muscle at a meeting point of muscles known as the perineal body.
The bulbo-spongious muscles are attached to the underside of this transverse partition the perineal membrane, which we'll see shortly. In addition, on each side a slender muscle runs parallel to the ischio-pubic ramus: it's the ischio-cavernosus muscle. The two bulbo-spongiosus muscles surround a mass of erectile tissue, the bulb of the vestibule. To see it we'll remove the bulbo-spongiosus muscles.
Here's the bulb of the vestibule. It's in two halves, which are joined together here, as we'll see. Buried within the ischio-cavernosus muscles, which we've also removed here, are two separate erectile bodies, the crura of the clitoris, which we'll see shortly.
To see all of the bulb of the vestibule, we'll remove the lining of the vestibule here. All this is the bulb of the vestibule. Its mid-line portion lies between the clitoris and the external urethral meatus. Directly behind the bulb on each side is the greater vestibular gland, which produces a watery secrection that lubricates the vaginal opening.
The perineal membrane lies directly above the bulb of the vestibule: we'll remove the bulb to see it. Here's the perineal membrane: it's a flat partition of fibromuscular tissue that bridges the space between the ischio-pubic rami.
The vestibule of the vagina, and the urethra pass though the perineal membrane. The posterior margin of the pubic symphysis is here, just in front of the urethra. Back here, above and behind the perineal membrane, we're looking into the ischio-rectal fossae, from which the fat has been removed.
This is the underside of the levator ani muscle. To see it better we'll remove the perineal membrane. Here's the right side of the levator ani, here's the left side. The levator ani is the principal component of the pelvic diaphragm, the sling of muscle that holds up the rectum, and also the vagina.