Plica semilunaris

9. Februar 2017 - Eye, Ophthalmology

The semilunaris plica is a small fold of the conjunctiva on the inner edge of the eye. It works during eye movement, helping to keep the tear drainage through the lacrimal sac , and allowing greater rotation of the eyeball, because without the conjunctiva escrow join directly to the eyeball, restricting movement. 1 is a vestigial remnant of the nictitating membrane (the „third eyelid“) which is drawn through the eye of protection, and is present in other animals such as birds , reptiles and fish , but is rare in mammals, in which are found mainly in the monotremes and the marsupials . 2 Your muscles are also vestigial partners. 3 No is fixed, therefore eye movements are not restricted by it. We only know of one species of primates , the calabar Arctocebus , which has this body fully functioning as nictitans. 4

With allergies eye, the eye wattle and semilunaris plica can become inflamed and itching may occur due to the release of histamine in tissue and in the tear film .

External links

  • + + conjunctival semilunar fold in the Dictionary of eMedicine


  1. Back to top↑ Dartt, Darlene A. (2006). „The Conjunctiva-Structure and Function“ . Duane’s Foundations of Clinical Ophthalmology 2 . Philadelphia: Lippincott Williams & Wilkins. Chapter 2 . Retrieved on November 8, 2012 .
  2. Back to top↑ Owen, R. 1866-1868. Comparative Anatomy and Physiology of Vertebrates . London.
  3. Back to top↑ Darwin, Charles (1871). The Descent of Man, and Selection in Relation to Sex . John Murray: London.
  4. Back to top↑ Montagna, W .; Machida, H .; Perkins, MS (1966). «The skin of primates XXXIII .: The skin of the angwantibo». American Journal of Physical Anthropology 25 (3): 277-290. doi : 10.1002 / ajpa.1330250307 . PMID  5971502 .