Tunica albuginea

Tunica albuginea: The whitish membrane within the penis that surrounds the spongy chambers (corpora cavernosa) in the penis and which helps to trap the blood in the corpora cavernosa, thereby sustaining erection of the penis. The term comes straight from the Latin tunica (covering or coat) + albuginea (white) = a covering that is white, like the white (albumen) of an egg.