Tunica albuginea

The penis consists of three components, two dorsolateral corpora cavernosa and a ventral corpus spongiosum that surrounds the penile urethra and distally forms the glans penis. The corpora cavernosa consist of blood-filled sinusoidal or lacunar spaces, which are lined with endothelial cells, supported by trabecular smooth muscle, and surrounded by a thick fibrous sheath called the tunica albuginea. The caver-nosal arteries, which are branches of the penile artery, penetrate the tunica albuginea and supply blood flow to the penis. 

The left cauda epididymis is sampled and used for the assessment of sperm motility. Sperm counts are performed using the left testis following removal of the tunica albuginea. In the case of an abnormality of the left epididymis or testis, the right organs may be used for sperm analysis. 

Lymphadenopathy is most often not clinically manifested however, bright yellow plaques and a cholesterol ester content 100-fold higher than normal have been documented for both normal-size and enlarged lymph nodes in Tangier patients. Biopsies of bone marrow and the affected tissues have revealed many foam cells that are smaller than those observed in lipid storage diseases. In addition, these cells contain sudanophilic deposits which are not membrane-bound, as is the case for lysosomal storage diseases. Foam cells have also been found in otherwise normal skin, ureters, renal pelvises, tunica albuginea (white fibrous capsule) of testicles, mitral and tricuspid valves, and aorta, coronary, and pulmonary arteries. 

It is enclosed in a tough fibrous capsule called the tunica albuginea (Figure 2). Within the seminiferous tubules, germ cells develop into spermatozoa in a process called spermatogenesis. The Leydig cells located between tubules in the testis interstitium... 

Careful evaluation of the normal tunica albuginea and of its changes is essential in virtually all penile pathologies. Major problems exist, however, to accomplish this task because of a series of artifacts produced by the ultrasound beam, such as specular reflection artifacts, speckle and shadowing. 

Finally, acoustic shadowing is less evident in the compound image, concentrated behind the attenuating structures. As a consequence, in penile imaging visualization of the dorsal aspect of the tunica albuginea is improved (Fig. 1.5). 

The corpora are surrounded by tunica albuginea, a strong structure of heterogenous thickness and anatomy, the purpose of which is to both provide rigidity of the erectile bodies as well as to function in the venoocclusive mechanism. 

The tunica albuginea consists of two layers, the outer of which is oriented longitudinally and the inner layer consisting of circular fibers. The inner layer contains struts that course the cavernosal space and... 

The venous drainage from the three corpora (Fig. 2.2b,c) originates in tiny venules leading from the peripheral sinusoids immediately beneath the tunica albuginea. These venules travel in the trabeculae between the tunica and the peripheral sinusoids to form the subtunical venular plexus before exiting as the emissary veins. 

Outside the tunica albuginea the skin and subcutaneous tissue drain through multiple superficial... 

Hsu GL, Brock G, Martinez-Pineiro L et al (1994) Anatomy and strength of the tunica albuginea its relevance to penile prosthesis extrusion. J Urol 151 1205-1208 Kim ED, Blackburn D, McVary KT (1994) Post-radical prostatectomy penile blood flow assessment with color flow Doppler ultrasound. J Urol 152 2276-2279 Wessells H, Lue TF, McAninch JW (1996) Penile length in the flaccid and erect states guidelines for penile augmentation. J Urol 156 995-997... 

The Colles fascia is barely visible in normal patients. The tunica albuginea and the Buck s fascia are stuck together and appear as a thin echogenic line surrounding the corpora, which became thinner during erection. Two distinct layers become ap-... 

The penile septum appears as an echogenic structure with back attenuation dividing the corpora cavernosa that can hamper visualization of the tunica albuginea in the dorsal aspect of the penis (Fig. 5.2). 

Fig. 5.2. Normal grey-scale ultrasound anatomy. Axial scan on the dorsal aspect of the penis showing the paired corpora cavernosa (CC), the corpus spongiosum (CS) and the penile septum (open arrows). The tunica albuginea (arrowheads) appears as a thin echogenic line surrounding the penile bodies. The Buck s fascia is visualized near the corpus spongiosum (curved arrows) while in the remaining portions is stuck on the tunica albuginea. The penile septum appears as an echogenic structure with back attenuation...

Fig. 5.13a-c. Duplex Doppler interrogation of cavernosal-spongiosal communcations. a Within the corpus cavernosum the vessel has an arterial waveform, whereas b after the passage of the tunica albuginea a venous waveform is recorded, c Doppler interrogation during full erection (cavernosal phase 4) shows diastolic flow disappearance or positive diastolic flow with systolic peak inversion... 

Immediately after the passage of the tunica albuginea, venous waveforms are recorded in the same vessels or arterial flows with very low vascular resistances. 

In patients with venous occlusive erectile dysfunction the cavernosal flow is elevated and easily detected. The vessels show an increased diameter and can be followed for a long course in the center of the corpus cavernosum. The helicine arterioles are numerous and visible up to the tunica albuginea... 

Akkus E, Carrier S, Baba K et al (1997) Structural alterations in the tunica albuginea of the penis impact of Peyronie s disease, ageing and impotence. Br J Urol 79 47-53... 

Brock G, Hsu GL, Nunes L et al (1997) The anatomy of the tunica albuginea in the normal penis and Peyronie s disease. J Urol 157 276-281... 

Hirano D, Takimoto Y, Yamamoto T et al (1997) Electron microscopic study of the penile plaques and adjacent corpora cavernosa in Peyronie s disease. Int J Urol 4 274-278 lacono F, Barra S, De Rosa G et al (1993) Microstructural disorders of tunica albuginea in patients affected by Peyronie s disease with or without erection dysfunction. J Urol 150 1806-1809... 

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