biology

Pelvic floor

Pelvic floor is a biology topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Pelvic floor rather than just read about it. In short: The pelvic floor or pelvic diaphragm is an anatomical location in the human body which has an important role in urinary and anal continence, sexual function, and support of the pelvic organs. The pelvic floor includes muscles, both skeletal and smooth, ligaments, and fascia and separates between the pelvic cavity from above, and the perineum from below.

Key takeaways

Pelvic floor belongs to biology; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Pelvic floor to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Pelvic floor from memory before moving on to harder problems.

Reference excerpt

The pelvic floor or pelvic diaphragm is an anatomical location in the human body which has an important role in urinary and anal continence, sexual function, and support of the pelvic organs. The pelvic floor includes muscles, both skeletal and smooth, ligaments, and fascia and separates between the pelvic cavity from above, and the perineum from below. It is formed by the levator ani muscle and coccygeus muscle, and associated connective tissue. The pelvic floor has two hiatuses (gaps): (anteriorly) the urogenital hiatus through which the urethra and vagina pass, and (posteriorly) the rectal hiatus through which the anal canal passes.

Structure

Definition Some sources do not consider "pelvic floor" and "pelvic diaphragm" to be identical, with the "diaphragm" consisting of only the levator ani and coccygeus, while the "floor" also includes the perineal membrane and deep perineal pouch. However, other sources include the fascia as part of the diaphragm. In practice, the two terms are often used interchangeably.

Relations The pelvic cavity of the true pelvis has the pelvic floor as its inferior boundary (and the pelvic brim as its superior boundary). The perineum has the pelvic floor as its superior boundary. Posteriorly, the pelvic floor extends into the anal triangle.

Function It is important in providing support for pelvic viscera (organs), e.g. the bladder, intestines, the uterus (in females), and in maintenance of continence as part of the urinary and anal sphincters. It facilitates birth by resisting the descent of the presenting part, causing the fetus to rotate forward to navigate through the pelvic girdle. It helps maintain optimal intra-abdominal pressure.

Clinical significance

The pelvic floor is subject to clinically relevant changes that can result in:

Anterior vaginal wall prolapse Cystocele (bladder into vagina) Urethrocele (urethra into vagina) Cystourethrocele (both bladder and urethra) Posterior vaginal wall prolapse Enterocele (small intestine into vagina) Rectocele (rectum into vagina) Apical vaginal prolapse Uterine prolapse (uterus into vagina) Vaginal vault prolapse (roof of vagina) - after hysterectomy Pelvic floor dysfunction can result after treatment for gynecological cancers. Damage to the pelvic floor not only contributes to urinary incontinence but can also lead to pelvic organ prolapse. Pelvic organ prolapse occurs in women when pelvic organs (e.g. the vagina, bladder, rectum, or uterus) protrude into or outside of the vagina. The causes of pelvic organ prolapse are not unlike those that also contribute to urinary incontinence. These include inappropriate (asymmetrical, excessive, insufficient) muscle tone and asymmetries caused by trauma to the pelvis. Age, pregnancy, family history, and hormonal status all contribute to the development of pelvic organ prolapse. The vagina is suspended by attachments to the perineum, pelvic side wall and sacrum via attachments that include collagen, elastin, and smooth muscle. Surgery can be performed to repair pelvic floor muscles. The pelvic floor muscles can be strengthened with Kegel exercises. Disorders of the posterior pelvic floor include rectal prolapse, rectocele, perineal hernia, and several functional disorders, including anismus. Constipation due to any of these disorders is called "functional constipation" and is identifiable by clinical diagnostic criteria.

Pelvic floor exercise (PFE), also known as Kegel exercises, may improve the tone and function of the pelvic floor muscles, which is of particular benefit for women (and less commonly men) who experience stress urinary incontinence. However, compliance with PFE programs often is poor, PFE generally is ineffective for urinary incontinence unless performed with biofeedback and trained supervision, and in severe cases it may have no benefit. Pelvic floor muscle tone may be estimated using a perineometer, which measures the pressure within the vagina. Medication may also be used to improve continence. In severe cases, surgery may be used to repair or even to reconstruct the pelvic floor. One surgery which interrupts pelvic floor musculature in males is a radical prostatectomy. With the removal of the prostate, many males experience urinary incontinence post operation; pelvic floor exercises may be used to counteract this pre and post operation. Pre-operative pelvic floor exercising significantly decreases the prevalence of urinary incontinence post radical prostatectomy. Prostatitis and prostatectomies are two contributors to erectile dysfunction; following a radical prostatectomy studies show that erectile dysfunction is improved by pelvic floor muscle training under the supervision of physical therapists certified in pelvic floor rehabilitation. Perineology or pelviperineology is a specialty dealing with the functional troubles of the three axes (urological, gynecological and coloproctological) of the pelvic floor.

Additional images

See also Coccyx (tailbone) Female genital prolapse Pelvic floor dysfunction Perineology Perineal hernia Pubococcygeus muscle Vaginal support structures Vesicovaginal fistula

References This article incorporates text in the public domain from page 420 of the 20th edition of Gray's Anatomy (1918)

External links Overview at nih.gov

Illustrations

Pelvic floor: Different positions to perform pelvic floor exercises — Different positions to perform pelvic floor exercises

Worked examples

Example 1 — a first encounter with Pelvic floor

Start with the simplest possible case. Write down what Pelvic floor claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Pelvic floor before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Pelvic floor ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Pelvic floor

In research: Pelvic floor appears in biology research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Pelvic floor in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Pelvic floor is common in secondary-school and first-year university syllabi. It links to neighbouring topics Muscles of the torso, Sexual anatomy, Women's health, so understanding it makes those chapters shorter.
In everyday life: Look for Pelvic floor outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Pelvic floor in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Pelvic floor means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Pelvic floor out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Pelvic floor in simple terms?

Why does Pelvic floor matter?

Because it connects several biology ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Pelvic floor?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Pelvic floor.