Biology:Retractor muscle of the penis
In some animals, the male penis possesses a muscle enabling retraction into the prepuce.
In particular animals
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]
References
- ↑ Bassett, E. Gertrude. "Observations on the retractor clitoridis and retractor penis muscles of mammals with special reference to the ewe." Journal of anatomy 95.Pt 1 (1961): 61.
- ↑ Rue III, Leonard Lee (2004-11-01). The Deer of North America. Globe Pequot. p. 312. ISBN 9781592284658. https://books.google.com/books?id=ni6Hbqm04vIC&pg=PA312. Retrieved 2 March 2013.
- ↑
"Genus summary for Tandonia". AnimalBase, last modified 23 May 2010, accessed 26 August 2010.
- ↑ 4.0 4.1 Sarkar, A. (2003). Sexual Behaviour In Animals. Discovery Publishing House. ISBN 978-81-7141-746-9.
- ↑ "The Stallion: Breeding Soundness Examination & Reproductive Anatomy". University of Wisconsin-Madison. Archived from the original on 2007-07-16. https://web.archive.org/web/20070716140038/http://www.wisc.edu/ansci_repro/101equinelab/reproduction/stallion_exam.html. Retrieved 7 July 2007.
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