Posts Tagged ‘penile roots’

No Erections Without A Solid Base

May 27, 2017

Andrew Siegel MD  5/27/2017  Happy Memorial Day Weekend!

A flagpole needs a solid base of support in order to stand tall and not be felled by the elements.  One that is poorly mounted will falter as soon as the wind picks up or other adverse circumstances surface.  This is analogous to a tree and its root system with no tree able to stand tall and bear the elements without a deep and powerful root system.  In both cases, the hidden, behind-the-scenes support system is equally important to the exposed product.


Flagpole base


Exposed roots of a mango tree, by Aaron Escobar [CC BY 2.0 (, via Wikimedia Commons

…And so it is with the penis. Like the flagpole and the tree that require a solid base of support, the penis also necessitates a sturdy foundation in order to be able to morph into a “proud soldier,” tall and erect in posture.  This foundation also enables the ability to maintain this rigid stability despite exposure to the “elements”– the substantial torquing and buckling forces the penis is subjected to at the time of sexual activity.

* Thank you to Paul Nelson–friend, colleague and president of the Erectile Dysfunction Foundation and launcher of–who came up with the clever  flagpole analogy.

What You See is Not What You Get

Half the penis is exposed and half is hidden.  The visible portion of the penis (pendulous penis) is the external half.  The internal half (infrapubic penis) lies under the surface and is known as the penile roots or in medical speak, the crura. Like the roots of a tree or the base of a flagpole responsible for foundational support, the roots of the penis stabilize and support the erect penis so that it stays rigid and skyward-angling with excellent “posture.”  Without functioning penile roots, the penis would remain limp, would dangle in accordance with gravity and have slouching posture at best.


Illustration above by Christine Vecchione from “Male Pelvic Fitness: Optimizing Sexual & Urinary Health”

The penile roots are enveloped by two pelvic floor muscles, the BC (bulbocavernosus) and the IC (ischiocavernosus).  These rigidity muscles compress the roots of the penis, causing backflow of pressurized blood into the penis.  In a sexual situation, these muscles engage and contract, forcing blood within the roots of the penis into the external penis.  Not only is pressurized blood pushed into the external penis promoting rigidity, but also the contractions of these muscles causes the clamping of venous outflow—a tourniquet-like effect—that results in penile high blood pressure and full-fledged rigidity.  These muscles are also responsible for ejaculation—rhythmically compressing the urethra (urinary channel that runs through the penis) at the time of climax to cause the expulsion of semen.

Factoid: It is the BC and IC muscles that are responsible for the ability to lift one’s erect penis up and down (wag the penis) as they are contracted and relaxed.

00001Illustration above by Christine Vecchione from “Male Pelvic Fitness: Optimizing Sexual & Urinary Health”

The BC and the IC muscles together with the transverse perineal muscles and the levator muscles are collectively known as the pelvic floor muscles, a muscular hammock located between scrotum and anus  (“inner taint”). Although unseen and behind-the-scenes, hidden from view, these often unrecognized and misunderstood muscles have vital functions in addition to erection and ejaculation, including urinary and bowel control. As part of the core group of muscles, they affect posture, the lower back and the hips.

Take home message: The pelvic floor muscles are the rigidity muscles, necessary for transforming the stimulated penis that becomes plump into a rock-hard penis. When these muscles are not functioning optimally, one loses the potential for full rigidity.

Factoid: An erection—defined in hydraulic terms—is when the penile blood inflow is maximized while outflow is minimized, resulting in an inflated and rigid penis. The pressure in the penis at the time of an erection is sky-high (greater than 200 millimeters), the only organ in the body where high blood pressure is both acceptable and necessary for healthy functioning. This explains why blood pressure pills are the most common medications associated with erectile dysfunction.

Bottom Line: Neither flagpole, tree nor penis can be firmly supported without a solid foundation.  The penile roots and the pelvic floor muscles that surround them are the foundation.  Not only do these muscles support the deep roots of the penis, but they are also responsible for the high penile blood pressures responsible for erectile rigidity and are the motor power underlying ejaculation.  The IC muscle should be known as the “erector muscle” and the BC muscle the “ejaculator muscle.” Although not muscles of glamour, they are certainly muscles of “amour.”

Straddling the gamut of being vital for what may be considered the most pleasurable and refined of human pursuits—sex—they are equally integral to what may be considered the basest of human activities—bowel and bladder function.  These hidden muscles deserve serious respect and are capable of being intensified by training in order to improve and often prevent sexual, urinary and bowel issues. Why not consider exercising your erector and ejaculator muscles, as you do for so many other muscle groups in the body?

Wishing you the best of health,

2014-04-23 20:16:29

A new blog is posted every week. To receive the blogs in the in box of your email go to the following link and click on “email subscription”:

Dr. Andrew Siegel is a practicing physician and urological surgeon board-certified in urology as well as in female pelvic medicine and reconstructive surgery.  Dr. Siegel serves as Assistant Clinical Professor of Surgery at the Rutgers-New Jersey Medical School and is a Castle Connolly Top Doctor New York Metro Area, Inside Jersey Top Doctor and Inside Jersey Top Doctor for Women’s Health. His mission is to “bridge the gap” between the public and the medical community that is in such dire need of bridging.

Author of MALE PELVIC FITNESS: Optimizing Sexual & Urinary Health

Author of THE KEGEL FIX: Recharging Female Pelvic, Sexual and Urinary Health

Co-creator of the PelvicRx male pelvic floor exercise program:







Getting in Touch with Your Inner Penis

August 5, 2014


Andrew Siegel MD Blog # 166




When I use the term “inner penis,” I am not referring in a new age meditative kind of way to the unexpressed, indiscernible, and unacknowledged spiritual-mental-emotional drive underpinning male sexuality (although that is a good topic for another day). Nah, not at all… I am referring to the physical, not metaphysical, literal inner part of the penis. Did you have any clue that one half of the penis is actually internal while the other half is external, that is, what you see? So, with this newfound knowledge, if you are ever in a situation where someone infers that your penile stature is less than imposing, you can confidently state that you are well hung, but internally!

Why do we have an inner penis at all? It seems to be such a waste of human flesh, doesn’t it? Well, it is not a waste and is actually very clever engineering—we have an inner penis for the same reason a house has a foundation and a tree has roots. Without solid foundational support, we would never be able to support a rigid erection, angling proudly up towards the heavens. If the purpose of the penis was only to conduct urine and there was no need for erectile rigidity, there would be no need for such support. However, in order to defy gravity and stand tall and proud at the appropriate times, the penis must have strong roots. If a house had a weak foundation, it could easily blow down in a storm and if a tree has a poor root system, a gust of wind could level it, and so robust penile foundational support is a necessity for supporting a rigid erection and allowing it to survive in the “stormy turbulence” it may encounter with sexual activity, a virtual tornado (hopefully) if you will.

Let’s briefly study the anatomy of the penis: The pendulous penis (hanging like a pendulum) is the external and visible portion of the penis, which, again, represents only about half of the penile length. The penile shaft extends from the base of the penis (where the penis attaches to the body in the pubic region) to the glans (the head of the penis, derived from the Latin word for acorn). The infrapubic penis (“below” the pubic bone) is the inner, hidden, deeper aspect of the penis that extends down the pubic bones on each side. The crura are the deep penile roots, which are secured to the bones and provide the internal support necessary for an erection.

The bulk of the tissue of the penile shaft is composed of three erection chambers that contain spongy, vascular erectile tissue: the paired corpora cavernosa (cave-like bodies) and the single corpus spongiosum (spongy body). Although they are individual cylinders, the corpora cavernosa are interconnected and communicate. The corpora cavernosa run parallel down the shaft of the pendulous penis, and diverge at the level of the inner component of the penis, forming the crura that are anchored to the pelvic bones. The urethra (channel that conducts urine and semen) is enveloped by the corpus spongiosum, which begins in the perineum (area between the scrotum and anus), where it expands to form the bulb and extends to and forms the glans penis. It lies in the groove between the corpora cavernosa.

If you imagine your body to represent the penis, your legs are your crura, your torso is the external penis, and your head is the glans. In order for your torso and head to stand tall and erect, you need your legs planted firmly in the earth; otherwise, your torso would crumble to the ground.

Important and intimately connected allies of your inner penis are the pelvic floor muscles, which work with the erection chambers of the penis. The two important pelvic floor muscles involved with sexual function are the bulbocavernosus (BC) and ischiocavernosus (IC) muscles. The BC surrounds the inner, deeper portion of the urethra and covers and compresses the bulb of the penis. It is really a compressor muscle, so I call it the urethral compressor. In its relaxed state, it acts as an internal strut that helps anchor the deepest, internal aspect of the penis. When the muscle is contracted actively after urination, it compresses the urethra to expel the last few drops of urine that remain in the deep urethra. During sex, it helps support the tumescent (swollen) corpus spongiosum and glans. At the time of climax, this muscle is responsible for the expulsion of semen by virtue of its strong rhythmic contractions, allowing ejaculation to occur and contributing to orgasm. The classic 1909 textbook Gray’s Anatomy aptly labeled the BC muscle as “ejaculator urine.”

The paired IC muscles cover and compress each corpus cavernosum of the penis. They, too, are really compressor muscles, so I call them the corporal compressors. In their relaxed state, they act as internal struts that help anchor the deepest aspect of the corpora—the crura—to the perineum. The IC stabilize the erect penis and compress the corpora, decreasing the return of blood to help maintain penile rigidity and sky-high blood pressures in the penis. At the time of climax, they contract rhythmically and are responsible for maximal erectile rigidity at the time of ejaculation. The 1909 Gray’s Anatomy aptly labeled the IC “erector penis.”

I like to think of the BC and IC muscles together as the levator penis since when contracted, they cause an upward deflection of the erect penis. You have the capacity to “point” your penis by virtue of your BC and IC muscles.



So there it is…you are now in touch with your inner penis and knowledge is power. Your inner penis and your pelvic floor muscles that compress it at the time of an erection are essential for optimal erectile rigidity and performance. Keep your pelvic floor muscles fit with targeted pelvic floor muscle exercises and your inner and outer penis will be grateful.

Wishing you the best of health,

Andrew Siegel, M.D.

2014-04-23 20:16:29


A new blog is posted every week. To receive the blogs in the in box of your email go to the following link and click on “email subscription”:

Author of: Male Pelvic Fitness: Optimizing Sexual and Urinary Health; available in e-book (Kindle, iBooks, Nook, Kobo) and paperback:

Private Gym website where pelvic floor instructional DVD and resistance training equipment are now available: