The tunica vaginalis is a pouch of
serous membrane within the scrotum that lines the
testis and
epididymis (visceral layer of tunica vaginalis), and the inner surface of the scrotum (parietal layer of tunica vaginalis). It is the outermost of the three layers that constitute the capsule of the testis, with the
tunica albuginea of testis situated beneath it.
It is the remnant of a pouch of peritoneum which is pulled into the scrotum by the testis as it descends out of the abdominal cavity during foetal development.
Anatomy
Visceral layer
The visceral layer of tunica vaginalis of testis (lamina visceralis tunicae vaginalis testis) is the portion of the tunica vaginalis that covers the testis and
epididymis. It is the superficial-most of the three layers that constitute the capsule of the testis, with the
tunica albuginea of testis situated deep to it. Posteriorly, the visceral layer does not line the surface of the testis - instead, it passes onto the
epididymis where the latter attaches to the testis before continuing onto the inner surface of the scrotum as the parietal layer.
Parietal layer
The parietal layer of tunica vaginalis of testis (lamina parietalis tunicae vaginalis testis)
is the portion of the tunica vaginalis that lines the inner surface of the
scrotum.
It is supported by the
internal spermatic fascia.
Cavity of the tunica vaginalis

The cavity of the tunica vaginalis
(also: cavum of the tunica vaginalis,
or cavum vaginale) is the cavity between the visceral layer and the parietal layer of tunica vaginalis. It is normally occupied by a small amount of clear, lightly coloured
fluid
In physics, a fluid is a liquid, gas, or other material that may continuously motion, move and Deformation (physics), deform (''flow'') under an applied shear stress, or external force. They have zero shear modulus, or, in simpler terms, are M ...
.
The volume of the fluid in the cavity may
increase abnormally when lymphatic drainage is impeded (due to inflammation, neoplasm, or trauma).
Development
The tunica vaginalis is derived from the
vaginal process of the
peritoneum, which in the
fetus
A fetus or foetus (; : fetuses, foetuses, rarely feti or foeti) is the unborn offspring of a viviparous animal that develops from an embryo. Following the embryonic development, embryonic stage, the fetal stage of development takes place. Pren ...
precedes the descent of the
testes from the
abdomen
The abdomen (colloquially called the gut, belly, tummy, midriff, tucky, or stomach) is the front part of the torso between the thorax (chest) and pelvis in humans and in other vertebrates. The area occupied by the abdomen is called the abdominal ...
into the
scrotum.
The vaginal process between the
abdominal inguinal ring and the superior part of the testis is then obliterated, usually leaving a string-like or cord-like remnant adjacent to the
spermatic cord.
If the vaginal process fails to obliterate, the communication between the peritoneal cavity and scrotum persists after birth, predisposing the individual to
indirect inguinal hernia, and
hydrocele testis.
Diseases
*
Mesothelioma
*
Hydrocele
* Cartilaginous bodies
*
Hematocele
References
External links
Diagram at aspiruslibrary.org* - "Inguinal Region, Scrotum and Testes: Tunic"
*
* ()
Mammal male reproductive system
Scrotum
{{Portal bar, Anatomy