Posts Tagged ‘corpus spongiosum’

Urethral Stricture: What You Need to Know

December 29, 2018

Andrew Siegel MD  12/29/2018

A urethral stricture is scarring within the urethra (the channel that conducts urine out of the bladder), resulting in a narrowed diameter and obstructive lower urinary tract symptoms.  The urethra is one of the parts of the body that is a particularly bad place for scarring, since it is a highly functional structure that is put into use numerous times daily.

The Male Urethra


Attribution  of image above: OpenStax Anatomy and PhysiologyOpenStax [CC BY 4.0 (, via Wikimedia Commons


urethral stricture

Image above indicates the great variety of strictures in terms of length and depth


Urethral strictures, although occasionally present in females, are much more common in males. The male urethra begins at the neck of the urinary bladder and ends at the tip of the penis. The innermost portion of the urethral is enveloped by the prostate gland. Thereafter the urethra runs through the perineum (between scrotum and the anus) where it is enveloped by the corpus spongiosum–a thick, vascular, cushiony structure– and thereafter the urethra extends through the penis (also surrounded by the corpus spongiosum) where it ends at the urethral meatus (the slit-like opening).

Urethral scarring results in a narrowed or blocked passageway that can give rise to obstructive voiding including one or more of the following symptoms: slow, weak, hesitant, spraying and intermittent urinary stream, prolonged emptying, incomplete emptying or inability to empty, painful urination and blood in the urine.  It can also cause urinary infections, bladder stones and cause difficulties/pain with ejaculation.

Urethral strictures often result from trauma, infection or inflammation.  External trauma can be caused by either a straddle injury (when the perineum abruptly strikes a fence or bicycle top tube) or a crush injury. Internal injury is often due to passage of urethral instruments, indwelling urethral catheters, or transurethral surgery. Inflammatory processes such as urethritis and sexually transmitted diseases also can result in urethral stricture formation.

When a urethral stricture is suspected, a urinary flow rate and an ultrasound-guided determination of how much urine is left in the bladder after urinating are obtained. These painless and noninvasive procedures will precisely characterize the extent of compromised urinary flow as well as the ability to effectively empty the bladder. Most strictures cause poor flow rates and elevated bladder residuals. Urethroscopy is a procedure in which a narrow, flexible, lighted instrument is placed in the urethra in order to directly examine it, ascertaining the location, extent and length of the stricture.  At times, imaging studies of the urethra–retrograde urethrogram, voiding cysto-urethrogram, or urethral ultrasound are performed to gain further information.  With urethroscopy and imaging studies, the location, length, and depth of the scar and degree of extension into the spongy tissue that surrounds the urethra can be deduced.

Mild strictures can be managed with simple urethral dilation that may be curative. This involves the passage of sequentially larger dilating instruments through the stricture to open up the scar tissue. If a urethral stricture is short and involves only the urethra or superficial spongy tissues in the bulbar urethra (the portion that travels through the perineum), optical internal urethrotomy is often the treatment of choice. This is a procedure done under anesthesia that utilizes an endoscopic instrument to incise open the urethra. Typically, a catheter is left in the urethra for several days thereafter to maintain the opening that has been made.  This procedure can be performed on an outpatient basis.  It will not always be curative because scar tissue can and often does recur. Dilation and optical urethrotomy are best for relative short strictures located in the bulbar urethra with success rates in the 35-70% range, often with the need for a repeat procedure because of recurrent scarring.

A useful tool after dilation or optical urethrotomy is to teach the patient self-catheterization to maintain the urethral opening. If obstructive symptoms recur and studies demonstrate little or no improvement, an open surgical treatment called urethroplasty can be a consideration. It is rarely necessary as an initial therapeutic option, but is appropriate for longer and recurrent urethral strictures or those involving extensive scarring. Excision of the stricture with urethroplasty has a 90-95% success rate, although it is a much more involved procedure than dilation or optical urethrotomy. If the stricture is located in the penile urethra as opposed to the bulbar urethra, urethroplasty should be offered since strictures at this location are less likely to respond to dilation or optical urethrotomy. Lengthy strictures require graft material to repair, often buccal mucosa ( graft material harvested from inside the mouth).

At times the stricture is confined to the part of the urethra located at the tip of the penis where it is known as a urethral meatal stricture.  This situation can be rectified with dilation or a minor procedure called a meatotomy/meatoplasty.

Wishing you the best of health,

2014-04-23 20:16:29

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Dr. Andrew Siegel is a physician and urological surgeon who is board-certified in urology as well as in female pelvic medicine and reconstructive surgery.  He is an 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.

Dr. Siegel has authored the following books that are available on Amazon, iBooks, Nook and Kobo:

MALE PELVIC FITNESS: Optimizing Sexual & Urinary Health

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

PROMISCUOUS EATING: Understanding and Ending Our Self-Destructive Relationship with Food

MPF cover 9.54.08 AM

These books are written for educated and discerning men and women who care about health, well-being, fitness and nutrition and enjoy feeling confident and strong.

Dr. Siegel is co-creator of the male pelvic floor exercise instructional DVD (female version is in the works): PelvicRx

New video on female pelvic floor exercises:  Learn about your pelvic floor


Penile Erection Geometry

June 7, 2014




(Illustration credited to Dr. Henry Gray, Gray’s Anatomy of the Human Body, 20th edition, original publication 1918, public domain)

Blog # 156

A flaccid penis is soft like a marshmallow and dangles limply from its attachment to the pubic bone. With stimulation, the penis fills, firms, and increases in length and girth, as tumescence turns to rigidity. Not only does the penis undergo a metamorphosis into a rigid erection, but it also starts angling up towards the heavens—majestically pointing towards the sky, a marvel of human hydraulic engineering in defiance of the laws of gravity. At its extreme, the erect penis can touch the abdominal wall. A young man’s erection can easily support the weight of a towel.

Who Knew? Birthday and New Year’s Eve party blowouts—those party toys that when blown unfurl and extend outwards—are a useful means of thinking about erections. In the flaccid state, the erectile cylinders are very similar to the party blowout when it is not being blown into; in the erect state, the erectile cylinders are comparable to the party blowout when it is being blown into.  In the flaccid state, there is an acute bend at the junction of the external and internal penis. With a rigid erection, this acute angle is lost and the external penis develops an obtuse angle relative to the internal penis.

Analogous to penile size, there is a great amount of variability in the angle of the erect penis relative to the body (the pubo-penile angle). Like belly buttons that can be “outies” or “innies,” erections can be “uppies” or “outies,” depending on a number of factors. “Flagpoles” can be vertical, horizontal, or any angle in between.

Who Knew? In summer camp there was always that smart aleck camper who cited a complex equation of the physics of erection intensity, involving the “angle of the dangle,” “the heat of the meat,” “the direction of the erection,” “the dimension of the extension,” “the torque of the pork,” etc. Who knew that there was actually validity to some of these factors in determining the angle of erection!

The pubo-penile angle is determined by the following factors: the tension in the suspensory ligaments of the penis; the attachments of the penis to the pelvic bones; the size of the penis; the extent of the erection; and the tone and strength of the ischiocavernosus (IC) and bulbocavernosus (BC) muscles.

The suspensory ligaments support and maintain the erect penis in an upright position, essentially anchoring the base of the penis to the pubic bone. The tighter the ligaments are, the greater the potential upward angulation of the erect penis.

Who Knew? In an effort to increase penile length, some surgeons perform a procedure in which the suspensory ligaments of the penis are cut. What this actually does is to expose some of the internal penis, allowing more of the penis to hang outside the body. The price one pays for this sleight of hand is that one’s erection will no longer point majestically to the heavens. Essentially, one gains a bit of flaccid length and loses angle—robbing your Peter to pay Paul, literally!

As the suspensory ligaments provide support and anchorage of the external penis from above, so the attachments of the erectile cylinders to the pelvic bones provide support and anchorage of the internal penis from below. Every individual has different anatomy, and the variations in pelvic anatomy and support can engender variations in erectile angulation. In general, the more firm and secure the attachments are from below, the greater the potential foundation of support and the greater the potential upward angulation of the erect penis.

Who Knew? The internal, concealed penis that is attached to the pelvic bones can be thought of as the roots of a tree. Similarly, the external penis can be considered in terms of the trunk of a tree. Without a solid root system—the foundation—no tree can assume a tall and erect stature. But with a solid foundation, the penis, like the tree, has the support to point high to the heavens.

Penile size is generally inversely proportional to the potential for upward angulation. Largely due to the force of gravity, there is a tendency for less upward angulation with longer and heavier penises.

Conceptually easy to understand, if flaccid is considered a 0% erection and full rigidity is 100%, the greater the magnitude and extent of the erection, the greater the upward angulation.

There are two particularly important pelvic floor muscles called the bulbocavernosus (BC) and ischiocavernosus (IC) muscles. These muscles are crucial to male sexual function. There are a total of 3 erectile cylinders that form the bulk of the tissue of the penis. The solitary erectile cylinder known as the “corpus spongiosum” (“spongy body”) runs from the perineum (the area between the scrotum and anus)” through the length of the penis to the “glans,” the head of the penis. Its innermost, protuberant portion is known as the “bulb.” The corpus spongiosum contains the urethra (urinary channel) and during sexual stimulation, the corpus spongiosum and the glans become swollen and plump. The BC is the muscle that covers the penile “bulb.” The “corpora cavernosa” (“cave-like bodies”) are the paired erectile cylinders are responsible for rigid erections. The IC refers to the muscle that covers the inner, deep aspects of the corpora cavernosa.

Bulbocavernosus and ischiocavernosus muscle strength can factor strongly into erectile angulation. A voluntary contraction of the BC and IC muscles will cause the erect penis to deflect in an upwards direction. As the BC and IC muscles are flexed, one can easily observe movement of the external penis towards the heavens as the increased blood filling of the erectile cylinders nudges the external penis up. The better the tone and conditioning the BC and IC muscles, the greater the potential upward angulation of the erect penis.

We must accept what nature has given us regarding our suspensory ligaments, our attachments of the penis to the pelvic bones, and the size of our penises. However, the factors that we can modify are the extent of our erections and the strength of our IC and BC muscles. So if we want to maximize our pubo-penile angle, PFM exercises become of paramount importance

An erection needs to be hard enough to penetrate, but flexible enough to be able to negotiate the various “acrobatic” requirements of different sexual positions. So, although an erection that points to the heavens is a wonderful phenomenon, one that is so angled to the extent that it is inflexible will not help one’s performance in the bedroom.

Who Knew? The vagina is shaped like a banana, with its innermost and deepest part angling downwards toward the sacral bones. In order to accommodate female anatomy and position, a penis needs to be both rigid and flexible at the same time—“flexible rigidity,” to use an oxymoronic phrase. If one has a highly angled, inflexible erection, sexual positions such as the reverse cowgirl or woman on top leaning backwards can be painful and can potentially inflict damage to the penis, as well as prove uncomfortable for the woman.


Andrew Siegel, MD


The aforementioned is largely excerpted from my new book: Male Pelvic Fitness: Optimizing Sexual and Urinary Health; available in e-book (Kindle, iBooks, Nook) and coming soon in paperback.


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Priapism: Too Much of A Good Thing

December 20, 2012

Andrew Siegel. MD    Blog # 87



A rock-hard erection is a good thing—it is nature in action.  This remarkable change in physical state of our genitals enables us to have sexual intercourse and reproduce.  It is truly an ingenious design and feat of mechanical engineering.  However, when the system fails and an erection does not regress, it is not such a good thing—and in fact can negatively impact our sexual future.  This condition is known as priapism—an unwanted, persistent, painful erection that is not on the basis of sexual stimulation.  The word priapism is derived from the Greek and Roman mythological God of fertility named Priapus.  He is commonly portrayed in classical artwork as having disproportionally large genitals.

Although priapism is an uncommon medical disorder, it is important because of its major potential complications in terms of sexual destiny.  The potential risk when priapism occurs is mechanical damage to the penis. Although priapism is predominantly a male problem, it has been known to involve the female clitoris, the structure that is analogous to the male penis. However, clitoral priapism is an extraordinarily rare occurrence.

Erection mechanics

The penis consists of three cylinders: the solitary corpus spongiosum which contains the urethra (the channel that conducts urine out from the bladder), and the paired erectile cylinders called the corpora cavernosa (erectile bodies), which are anchored internally to the pubic bone and extend to the head of the penis. These erectile cylinders communicate with each other and are enclosed in a fibrous sheath.  The erectile cylinders contain spongy tissue that is endowed with a very rich blood supply. Under the circumstances of erotic or tactile stimulation, the sinuses of the corpora become engorged with blood, resulting in an erection. This seemingly simple process is actually a highly complex event requiring integrated functioning of the brain, nerves, blood vessels, and hormones.


Priapism can occur at any age, ranging from the pediatric to the geriatric population.  When it occurs in children, it is most commonly on the basis of sickle cell disease.  Although many cases of priapism in both adults and children have no clear-cut underlying cause, possibilities include leukemia; use of certain medications; dialysis; neurological infections; herniated discs; spinal cord stenosis; anesthesia; genitourinary cancer; and penile or perineal trauma.   Certain medications—particularly the vasoactive agents injected into the penis as a treatment for erectile dysfunction that has not responded to the commonly used oral medications including Viagra, Levitra and Cialis—are commonly implicated in causing priapism.

Broadly speaking, priapism can be divided into two types, ischemic priapism and non-ischemic priapism.  Ischemia refers to compromised blood flow.  Ischemic priapism is also called veno-occlusive or low-flow priapism and is marked by minimal fresh blood flow within the erectile cylinders the penis—the blood content is old, clotted blood.  It is similar to other compartment syndromes in the body in which there is high-pressure in a closed space with metabolic changes and tissue damage. Ischemic priapism is painful because of the lack of oxygenated (fresh) blood flow to the genital tissues as well as the increased pressure within the erectile cylinders from the erection. Ischemic priapism can ultimately cause tissue necrosis (cellular death of the erectile tissue) and fibrosis (scarring), damaging the erectile tissue such that erectile dysfunction will result.   Generally, if an episode of ischemic priapism persists for more than 4 hours, functional damage to the erectile tissue of the penis will occur.

Non-ischemic priapism is usually on the basis of trauma to the penis or the perineum, the anatomical section of the body located between the scrotum and the anal area. A typical scenario for non-ischemic priapism is a straddle injury resulting from the perineum striking a blunt object such as the top tube of a bicycle or a fence. Non-ischemic priapism is generally not painful.  As a result of the trauma to the blood vessels, an abnormal connection occurs between the artery to the erectile cylinders and the spongy tissue within the erectile cylinders.  This abnormal connection promotes increased blood flow and unregulated blood filling of the erectile cylinders. Non-ischemic priapism is also called arterial or high-flow priapism.

One important diagnostic study is putting a needle into the erectile cylinder of the penis and aspirating (drawing out) blood and submitting it for blood gas testing. In ischemic priapism, the blood is usually dark and sludgy and very low in oxygen content as opposed to patients with non-ischemic priapism who have bright red blood that is well oxygenated. Color duplex ultrasound is another diagnostic method for distinguishing between ischemic and non-ischemic priapism.

Ischemic priapism is treated by decompressing the erectile cylinders to counteract the ischemia and manage the pain.  Initial treatment is evacuating blood from the erectile cylinders and irrigating them to try to release the clotted blood, along with injection of a vasoconstrictor agent (medication that constricts blood vessels), while monitoring blood pressure and cardiac rhythm, since these vasoconstrictors can elevate blood pressure and pulse.  If the ischemic priapism has occurred over an extended duration, it is unlikely to resolve with such local treatment and surgical shunting will likely be necessary.  A surgical shunt is a means of trying to facilitate blood drainage from the erectile cylinders to another anatomical structure.

Management of non-ischemic priapism initially is simply observation. If it fails to resolve, the next step is selective arterial embolization (blocking the abnormal connection by injecting a clotting substance into the injured blood vessel), a procedure done in interventional radiology.

Bottom Line:  As the television commercials state, if you have an erection that lasts more than four hours, call your doctor.  An erection that is prolonged to this duration is truly a medical emergency and could be your last if you do not get help… pronto!

Andrew Siegel, M.D.

Author of Promiscuous Eating: Understanding and Ending Our Self-Destructive Relationship with Food:

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