Histologic Study of the Tunica Albuginea of the Penis and Mode of Cavernosus Muscles' Insertion in It

Abstract

The tunica albuginea (TA) is the outer covering of the corpora cavernosa (CCs) and corpus spongiosum (CS) of the penile shaft. The different histoanatomical patterns of the TA, as well as the mode of attachment of the ischio-/bulbo-cavernosus muscles (ICM, BCM) to the TA, were studied, aiming at elucidating their role in the mechanism of erection. Twenty-eight cadaveric specimens (18 adults, 10 neonatal deaths) were studied morphologically and histologically after staining with hematoxylin and eosin and Verhoeff-van Gieson stains. The TA consisted in 20 specimens of 2 layers: inner circular and outer longitudinal, in 6 specimens of 3 layers: inner circular, longitudinal and outer circular, and in 2 of only one longitudinal layer. The CS TA was formed of one layer of longitudinal fibers. The mode of cavernosus muscles insertion into the TA revealed 3 patterns. The conjoint BCM and ICM formed a fibrous belt over the CCs in 18 specimens, a muscular belt in 6 and no belt in 4. The functional role of the variations in the TA morphological structure is not exactly known. We hypothesize that the 3-layered TA gives more penile rigidity than the double and single layers. Considering the type of cavernosus muscles insertion into the TA, it appears that the fibrous belt exerts more CC compression than the other 2 types of insertion.

Role of Tunica Albuginea in Erection: Is It a Dynamic or a Static Role?

“…of erection was proposed [1,4,5,9,11,14,17,19]. The results of the study seem to support the suggestion that the TA does not play an essential role in the erectile mechanism.…”

“…It consists of collagen fibers impregnated with elastic fibers. It has various histologic patterns [11,17], the most common (71.4%) being the Margot Yehia assisted in preparing the manuscript.…”

Electrophysiologic Activity of the Tunica Albuginea and Corpora Cavernosa: Possible Role of Tunica Albuginea in the Erectile Mechanism

“…The second commonest (with an incidence of 21.4%) is the three‐layered pattern with an additional outer circular layer. The single‐layered TA is formed of circular fibers and occurs in only 7.2% [3]. Intracavernosal pillars arise from the inner layer and radiate into the corpora cavernosa (CC).…”

“…It consists of collagen fibers impregnated with elastic fibers [1,2]. It has various histologic patterns, the commonest being the two-layered TA (with an incidence of 71.4%), which consists of an inner circular and an outer longitudinal layer [2,3]. The second commonest (with an incidence of 21.4%) is the threelayered pattern with an additional outer circular layer.…”

“…The TA of the corpus spongiosum consists of only one layer of circular fibers [5]. The TA does not contain smooth muscle fibers [1][2][3][4][5].…”