3D Tour of the Pelvic Floor
Channel: About Medicine
Date: 2019-02-06

Pelvic floor anatomy in 3D (as it should be).

So what is the pelvic floor?

The pelvic floor is a collection of muscles and connective tissue, which sits at the bottom of the pelvic cavity. It provides structural support for the pelvic organs and assists in a number of functions, including defecation, sexual activity and childbirth.

You can view this model here: https://www.aboutmedicine.com.au/perineum


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Video Script

Here we see the pelvic cavity, otherwise known as the true pelvis.

It’s oblique superior border is the pelvic inlet.

At the bottom of the pelvic cavity is a bunch of muscles, some of which are collectively known as the pelvic floor.

We’ll be going through these pelvic floor muscles in this video.

Their main functions are:

- to support the abdominal and pelvic viscera
- to maintain continence of urine and faeces
- to assist voiding, defecation, sexual activity, and childbirth

The most significant contributors are the levator ani, which consists of three muscles: the pubococcygeus, puborectalis, and iliococcygeus. If we remove the pelvic bones now, they’re shaped like a bowl, or a hammock if you like.

They collectively insert on the anococcygeal raphe, a fibrous ridge in the midline, posterior to the rectum.

We then have coccygeus posteriorly to them.

When these muscles contract together, such as when you’re doing your Kegels, they tighten inward, and the outlets of the pelvic organs are constricted. Which is the rectum here, the vagina here as this is a female model, and the bladder here.

Lateral to levator ani are the ischiorectal fossae, which are spaces with fat and other tissue in, acting as a sort of cushion for these dome-shaped muscles, allowing space for the dome to expand into if necessary. 

A big bowel evacuation is one example.

We then have the perineal membrane, connective tissue running between the ischiopubic rami on either side.

Deep to that is the external urethral sphincter &... deep transverse perineal muscles, and superficial to that, so closer to the skin, we have the remaining pelvic floor muscles.

Bulbospongiosus takes on this shape in females, and round the back we have the superficial transverse perineal muscles. You may have noticed this guy, that’s the perineal body, which acts as an insertion point for the latter muscles we just mentioned, among other things.

Last but not least is the anal sphincter muscles, which also has fibres joining the perineal body and anococcygeal raphe. 


One of the more common pathologies associated with the pelvic floor is vaginal prolapse. 

This occurs when the pelvic floor muscles loosen and weaken, associated with disruption of the connective tissue supports around them. 

This U-shaped space in the levator ani we call the urogenital diaphragm. 

If its inadequately supported, the vagina can move down towards or through this diaphragm, which can cause persistent discomfort for that person. 

The vagina will extend through here because the pelvic muscles aren’t holding it in.