Stretching the Tunica

Gentlemen and Pirates,

This is what we’re up against. The info below of particular interest to our strange clan of tunica stretchers concerns

1. Tunica tensile strength. (I assume safe tunica stretching is about stretching the tunica beyond its maximum at erection over a period of time, allowing recovery and then doing it again…and not tearing it! Read last sentence. Ouch.)
2. Elastin as a component of tunica.
3. Flaccid to erect volume ratios.
4. Varying thickness and tensile strength of tunica in different parts of penis; Perhaps some angles of erect bends are more effective than others.
5. Even pressure throughout corpora cavernosa.

The tunica albuginea consists of layers of collagen which can accommodate a considerable degree of intracavernosal pressure prior to rupture. To function effectively, these fascial layers must provide the penis with a wall container capable of withstanding a high degree of rigidity and axial strength when erect, yet be supple when flaccid. The tunica must be able to elongate symmetrically and increase in girth with tumescence, assuring a straight erection. The tensile strength of the tunica is approximately 1200 - 1500 mmHg making this fascia one of the most strong in the body. Approximately 5% of the tunica is elastin which enables the penis to develop elongation. The average volume increase of the erect penis from the flaccid volume is 3-fold with a range from 1.7 - 5 fold. The mechanical properties of the tunica which allow for maximum volume changes of the erect penis are called tunica dispensability. Regions of the tunica with focal poor dispensability cause the erect penis to bend. This focal tunical abnormality in dispensability
is called Peyronie’s disease.

The substance of the corpora cavernosa (erectile tissue) consists of numerous sinusoids (lacunar spaces) among interwoven trabeculae of smooth muscles and supporting connective tissue. The corpora cavernosa sinusoids are widely communicative and larger in the center of the corpora, having a Swiss-cheese appearance. This fact enables the blood within the penis to transfer easily from the top to the bottom of the corpora. This also enable the penis
to have a common intracavernosal pressure and a common penile rigidity. The sinusoids are smaller in the periphery and have a grape-like appearance. Peripheral sinusoids have a greater individual surface area than central sinusoids. These characteristics aid in the passive process of corporal veno-occlusion by sub-tunical venule compression against the tunica albuginea. All lacunar spaces are lined with endothelial cells, thought previously to have only a slippery surface preventing blood clotting. Recent research has revealed that endothelial cells have secretory function and synthesize factors involved in the regulation of corporal smooth muscle tone.

http://www.ncbi .nlm.nih.gov/en … 1&dopt=Abstract

In 7 male cadavers the anatomical structure, thickness and tensile strength of the tunica albuginea of the penis, measured at specific locations, were determined. The tunica is composed of inner circular and outer longitudinal layers made up of collagen bundles. The outer layer appears to determine, to a large extent, the variation in thickness and strength of the tunica. The ventral groove (found between the 5 and 7 o’clock positions), which houses the corpus
spongiosum, lacks outer bundles and appears vulnerable to perforation. The thickness of the tunica measured at the 7, 9 and 11 o’clock positions was 0.8 +/- 0.1 mm, 1.2 +/- 0.2 mm and 2.2 +/- 0.4 mm, respectively. Differences in the thickness of the tunica at specific locations were statistically significant (all p < or = 0.018). Symmetrical measurements were nearly identical in a mirror image arrangement (3, 5 and 1 at the 9, 7 and 11 o’clock positions, respectively). The stress on the tunica at penetration (breaking point pressure) measured at the 7, 9 and 11 o’clock positions was 1.6 +/- 0.2 x 10(7) N/m.2, 3.0 +/- 0.3 x 10(7) N/m2 and 4.5 +/- 0.5 x 10(7) N/m.2, respectively. The strength and thickness of the tunica correlated in a statistically significant manner with location (r = 0.911 and p = 0.0001). The most vulnerable area is on the ventral aspect (which lacks the longitudinally directed outer layer bundles), where most prostheses tend to extrude. This finding supports our belief that prosthesis extrusion often has an anatomical basis and is not merely a phenomenon caused by infection or compression.

Upward erect bends would then direct the pressure on the ventral side where the tunica is at its weakest. So I guess you can have a thicker dick curved upwards.

Methinks additional girth in conjunction with a graceful upward curve could look quite fetching. And have practical applications for the g-spot.

Interesting post mass, good links also

Great post and links. Now for an attempt at maths, so please correct me if I am wrong.

They talk of failure at 1.6 +/- 0.2 x 10(7) N/m.2. This means failure at approx 1,600,000 kg/metre squared

Take a flaccid tunica circumference of 100mm with a thickness of 1mm. It has a cross section area of 0.0001metre square (0.1x0.001). This means it can handle hanging 160kg (0.0001x1,600,000) before failure. This doesn’t take into account the load taken by the other structures, just the tunica. Bib has hung up to 60lb which is 27kg.

Most plastics have a tensile strength of approx 30,000,000N/m.2 so it is 2 times stronger than the tunica, most steel is about 25 times stronger, at 400Mpa.

Feel free to verify or find fault in my figures.

So what does this tell me? I should rig up a 18 wheeler to my BIB hanger?

I think all of these are fine, but we are forgetting the force over time factor.

And they talk of the tunica “failing” or hangling X amount of lbs before failing. Forgive me, but I don’t want my tunica “failing” That can only mean something bad in this context, perhaps rupturing or ripping.

It is hard to tell what these numbers refer to unless you are familiar with the standards of the biomechanical material testing. A figure of 1200 mmHg I can only imagine refers to an internal pressure. Doing a conversion to US units, this means you don’t want to apply anywhere near 23 lbs of force onto a dick area of one square inch.

I don’t know what sort of tensile strength they are refering to in the other tests though. Your conversion is roughly correct by the way.

I tried calculating from the 1500mmHg first and found it would fail at about 20kg!

From the first link: The glans is devoid of tunica albuginea.

Perhaps any serious enlargement program should include glans-specific exercises. It’ll probably be the first part to show gains-might contribute to length gains as well. The first place I noticed glans enlargement was the corona (the pink ridge around the head where it joins the shaft)

I’d like to see this discussion move towards application so we can all get a grip on how to use this information. Since the information is excellent.

Based on this link:

The elasticity and the tensile strength of tunica albuginea of the corpora cavernosa - PubMed

It seems that the 1500mg Hg is internal pressure, based on a burst (herniation) test.

To put that in perspective, it is 29 PSI(G) .

What it does tell us is that the tunica is incredibly strong.

It is also interesting to note that a basketball is inflated to between 7 and 9 PSI.

I found one science fair project on the web that stated a basketball would only hold about 20 PSI (that leads one to believe that rupture occurred past a 20 PSI inflation pressure).

I did some research too and and I’ve found that tunica can be divided in two part:

Internal, with circonférential fibers
External, with longitudinal fibers.
This two part ar’nt attached.

Collagen can be extended permanently without fracture if it’s heated at 45°celcius and with light stretchs.
(Think about slowcooking)

Add a link to those researches Rizlo, please.

http://books.go ogle.fr/books?i … page&q=&f=false