You can help expand this article with text translated from
the corresponding article in German. (March 2013) Click [show] for important translation instructions.
|
In some animals, the male penis possesses a muscle enabling retraction into the prepuce.
The retractor penis muscle occurs in marsupials and carnivorans, but it is absent in humans. [1] A stag's penis forms an S-shaped curve when it is not erect, and is retracted into its preputial sheath by the retractor penis muscle. [2]
In Tandonia, the retractor penis inserts at the boundary between the penis and epiphallus. [3]
In stallions, the retractor penis muscle is relatively underdeveloped. [4] The retractor muscle contracts to retract the penis into the sheath and relaxes to allow the penis to extend from the sheath. [5]
In bulls, protrusion is not affected much by erection, but more by relaxation of the retractor penis muscle and straightening of the sigmoid flexure. [4]