Peyronie’s Disease – Special Interest Anatomy of the Penis and Related Areas
The penis is the male organ of reproduction and urinary elimination, located on the mid-line of thet lower abdomen at the level of the pubic bone, above the scrotum. It develops in the male embryo from a small mass of tissue that also forms the clitoris in the female embryo. If you want to get the most from your Peyronie’s treatment it is necessary to understand the anatomy of the penis.
The penis is actually made of three separate cylinders (two on top and one on bottom) of a special type of erectile tissue that are capable of filling with blood and becoming rigid. Each of the three cylinders is covered with a thin layer of thin but tough connective tissue, as well as being bound together as a group with that same type of thin tissue. The two top cylinders are called the “corpora cavernosa” because of the thousands of tiny caverns, or open spaces in the tissue that fill with blood during erection. The bottom cylinder is called the “corpora spongiosum” because it is composed of soft and spongy tissue; it has the “urethra” or urinary passage tube running through it from the bladder, and ends at the tip of the penis. As the corpora spongiosum nears the end of the penis, it flares out to form the “glans” or head of the penis that looks like a mushroom or cap on top of the two corpora cavernosa.
If you are interested in learning about Peyronie’s disease, then you must understand the special connective tissue layers below the skin surface of the penis. A particular tissue that is so important in any discussion of PD is a very thin membrane, called the tunica albuginea. It is made of connective tissue and it covers or wraps around the two corpora cavernosa cylinder bodies. Under the microscope it is possible to see that the tunica albuginea is not a solid structure but it is a laminated, or multilayer structure like pages of a book or layers of an onion. The tunica albuginea not only covers the penis structure once with this laminated tissue, it covers it twice. The first deep layer, shaped like a tube, encloses each of the two corpora cavernosa. Since the corpora cavernosa are located closely side-by-side, where the two cylinders touch along the mid-line the inner layer forms a band of tissue called a septum. The second layer of the tunica albuginea, also shaped like a tube but twice as large, goes around the pair of the corpora cavernosa. (Think of it this way: the two corpora cavernosa are like two hot dogs, side by side; each hot dog has a casing or cover on it; the two hot dogs and their casings are held together with another layer of casing to bind them together in a pair. Where the two hot dogs and casings touch each other, the two casings fuse to make the septum; the septum fuses also to the second casing layer to make a very strong and secure structure.)
Back to the penis : The septum of the deep inner layer attaches along the mid-line to the top and bottom section of the superficial outer layer, creating a structure that is almost like an I-beam. In addition, there is another or third layer of connective tissue around the two corpora cavernosa that is even more superficial than the tunica albuginea. It is another tubular layer of tissue, called Buck’s fascia, that gives the penis added rigidity when the corpora cavernosa fill with blood during erection. There are no nerve endings in the tunica albuginea, but there are nerve endings in Buck’s fascia. Any pain associated with PD comes from stretching or inflammation of Buck’s fascia, not the tunica albuginea.
The blood supply to the penis, by way of the internal pudendal artery, is abundant. Good blood circulation is required for the corpora cavernosa and corpora spongiosum to produce an erection. However, not all parts of the penis have or need a good supply of blood. As is typical of most connective tissue in the body, the tunica albuginea does not have a good blood supply – it doesn’t need it for the most part, although this poor blood supply works against it. When injured, the poor blood flow to the tunica albuginea causes it to heal slowly or poorly in some cases. The limited blood supply to the tunica is an important aspect of the anatomy of the penis that affects the outcome of Peyronie’s disease.
Therefore, keeping the blood flow to the penis as full as possible is vital to the health of this tissue and improves chances for its recovery after injury; lack of blood flow favors scar development. It is perhaps no coincidence that a study showed that out of 76 cases of PD 36% had arterial disease and 59% had obstructed venous drainage in the blood circulation to the penis.(1) Other research has also shown a mixture of circulation problems with the arteries and veins of men with PD.(2,3)
For these very important reasons, PDI treatment recommendations strongly emphasize therapy that will increase blood circulation to and from the penis. No where else have we found any authority to draw attention to, or correlate, this important anatomical or therapeutic factor.
Please refer to Figure 1, below, for details of normal penis anatomy, as well as detail of a scar (plaque) in the tunica albuginea that is shown to be distorting the penis.
Peyronie’s disease as it relates to male anatomy
…and This is How It Works… With a better understanding of the anatomy of the male organ of reproduction, it should be easier to understand how the male anatomy “comes to attention” when erect. If you wish to understand how this complicated, but fascinating, process of erection occurs, click on How an Erection Happens.
Soft Tissue of the Pelvis
“Soft tissue” is a general anatomy term that refers to a broad group of supporting and connecting tissues of the skeleton that are not hard: skin, muscle, tendon, ligament and fascia (a thin delicate membrane of connective tissue found throughout the body that surrounds and covers internal organs, muscles and related soft tissue structures, almost like Saran plastic wrap ) . In particular, this discussion is most concerned with the soft tissue directly or indirectly associated with the penis. These soft tissues are the various layers of muscles, tendons, ligaments and fascia of the lower pelvic floor, inguinal or groin region and the lower abdominal wall around the pubic bone especially. Please refer to Figure 2, below, for a general idea of these different tissues, and their relationship to the male genital organ. What makes these soft tissues so important to PD is their influence on the blood supply and the lymphatic drainage (see below) to the genital area.
Lymphatic Drainage of the Pelvis
Simply, the lymph system is the sewer system of the body. It consists of a large network of lymph vessels (much like veins), that carry a clear fluid called lymph (much like plasma). Along the pathway of these lymph vessels, from place to place, there are small bean-shaped bodies of tissue (called lymph nodes) that serve as filters. Refer to figure 3, below, to see how all of this is connected. These are the same type of lymph nodes that become tender and swollen under your jaw when you have a sore throat.
Lymph nodes are distributed throughout the body, including the groin and deep in the lower pelvis where you cannot touch them. The purpose of the lymph system is to remove infection, cellular debris and toxins from every part of the body. The final destination of the lymph fluid in the lymph vessels is to enter into the liver for final disposal and elimination via the gall bladder. Every part of the body needs a full and uninterrupted movement of lymph fluid in both directions, in and out. If there is poor movement or flow of lymph, then toxins accumulate and fluid starts to collect, like a backed-up sewer.
The lymph fluid is moved along in the lymph vessels by gravity and by internal massage and pressure from those tissues that lay along side the lymph vessels. Spasm, contraction and shortening of various soft tissues can constrict the lymph vessels and cause backing up and stagnation of lymph – again much like a backed up sewer. For any tissue, organ or area of the body to be healthy – the penis included – a good lymph circulation must service it, just like your house needs a good sewer system. With poor lymph circulation, tissue becomes easily diseased and does not heal well. Figure 3, below, illustrates the abundant lymphatic supply to the lower pelvis and genital region.
To view graphic pictures of Peyronie’s disease, click on Peyronie’s pictures
Summary of special discussion of Peyronie’s disease anatomy
The tunica albuginea normally has a limited blood flow, and therefore poor oxygen supply because it is more like a tendon in nature; tendons generally don’t need and don’t have a huge blood supply. This is critical in understanding how the scar develops in the tunica in first place and how treatment should proceed. Like all parts of the body, if the blood supply and lymphatic drainage of the lower pelvis and penis are not correct, trouble can start. PDI treatment suggestions take these things into account.
Various therapies are suggested in this website that improve the oxygen content and oxygen carrying capacity of the blood, improve blood supply and lymphatic drainage, increase nutrient support to the soft tissue structures of the genital area, and improve the capacity of the body to heal and repair damaged tissue. This is the connection of the anatomy and the therapy that is offered for your review. In the 14-part “Treatment Options” section you will find many different therapies that attempt to support and benefit the blood and lymphatic supply to and from the lower pelvis. With a better understanding of the structure and complexity of this area of your body, you should be able to participate in your treatment plan with a far better appreciation of your problem and your purpose in following your treatment plan.
You now know the penis is made of several unique tissues, and these are directly affected in Peyronie’s disease. Recall that specialized tissue of the penis has spaces like “caves” and one area is like a “sponge”, both of which fill with blood to create an erection. Even though the cavernosa and the spongiosum have a huge blood supply, right next to them is the tunica albuginea with a poor blood supply. Throughout this website we will refer over and over again to the tunica albuginea, the corpora cavernosa, the corpora spongiosum, lymphatic flow, and connective tissue. Understanding this anatomy will help you to later understand the unique therapies we suggest for Peyronie’s disease. Now you know.
1. Levine LA, Coogan CL: Penile vascular assessment using color duplex sonography in men with Peyronie’s disease. J Urol, 155: 1270-1273, 1996. 2. Lopez JA, Jarow JP: Penile vascular evaluation of men with Peyronie’s disease. J Urol, 149: 53-55, 199 3. Burford CE, Glen JE, Burford EH: Fibrous cavernositis: further observation with report of 31 additional cases. J Urol, 49: 350-356, 1943.