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In humans, the spleen is brownish in color and is located in the left upper quadrant of the abdomen.<ref name="Mebius"/><ref>{{cite book|author=Loscalzo, Joseph; Fauci, Anthony S.; Braunwald, Eugene; Dennis L. Kasper; Hauser, Stephen L; Longo, Dan L. |title=Harrison's principles of internal medicine |publisher=McGraw-Hill Medical |location= |year=2008 |pages= |isbn=978-0-07-146633-2 |oclc= |doi=|accessdate=}}</ref>
In humans, the spleen is brownish in color and is located in the left upper quadrant of the abdomen.<ref name="Mebius"/><ref>{{cite book|author=Loscalzo, Joseph; Fauci, Anthony S.; Braunwald, Eugene; Dennis L. Kasper; Hauser, Stephen L; Longo, Dan L. |title=Harrison's principles of internal medicine |publisher=McGraw-Hill Medical |location= |year=2008 |pages= |isbn=978-0-07-146633-2 |oclc= |doi=|accessdate=}}</ref>


==Anatomy==
==Structure==
<!--(Put anatomy here)-->

The spleen, in healthy adult humans, is approximately {{convert|27|cm}} to {{convert|14|cm}} in length. It usually weighs between {{convert|150|g}}<ref>[http://emedicine.medscape.com/article/206208-overview eMedicine > Splenomegaly] Author: David J Draper. Coauthor(s): Ronald A Sacher, Emmanuel N Dessypris, Lewis J Kaplan. Updated: Oct 4, 2009</ref> and {{convert|200|g}}.<ref name=spielmann>{{cite journal | last=Spielmann | first=Audrey L. | coauthors=David M. DeLong, Mark A. Kliewer | title=Sonographic Evaluation of Spleen Size in Tall Healthy Athletes | journal=American Journal of Roentgenology | volume=2005 | issue=184 | pages=45–49 | publisher=American Roentgen Ray Society | url=http://www.ajronline.org/cgi/content/abstract/184/1/45 | accessdate=2008-09-09 | pmid=15615949 | date=1 January 2005 | doi=10.2214/ajr.184.1.01840045}}</ref> An easy way to remember the anatomy of the spleen is the 1×3×5×7×9×11 rule. The spleen is 1" by 3" by 5", weighs approximately 7 oz, and lies between the 9th and 11th ribs on the left hand side.
The spleen, in healthy adult humans, is approximately {{convert|27|cm}} to {{convert|14|cm}} in length. It usually weighs between {{convert|150|g}}<ref>[http://emedicine.medscape.com/article/206208-overview eMedicine > Splenomegaly] Author: David J Draper. Coauthor(s): Ronald A Sacher, Emmanuel N Dessypris, Lewis J Kaplan. Updated: Oct 4, 2009</ref> and {{convert|200|g}}.<ref name=spielmann>{{cite journal | last=Spielmann | first=Audrey L. | coauthors=David M. DeLong, Mark A. Kliewer | title=Sonographic Evaluation of Spleen Size in Tall Healthy Athletes | journal=American Journal of Roentgenology | volume=2005 | issue=184 | pages=45–49 | publisher=American Roentgen Ray Society | url=http://www.ajronline.org/cgi/content/abstract/184/1/45 | accessdate=2008-09-09 | pmid=15615949 | date=1 January 2005 | doi=10.2214/ajr.184.1.01840045}}</ref> An easy way to remember the anatomy of the spleen is the 1×3×5×7×9×11 rule. The spleen is 1" by 3" by 5", weighs approximately 7 oz, and lies between the 9th and 11th ribs on the left hand side.


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* In mice, the spleen stores half the body's [[monocyte]]s so that upon injury they can migrate to the injured tissue and transform into [[dendritic cell]]s and [[macrophage]]s and so assist [[wound healing]].<ref name="Swirski"/>
* In mice, the spleen stores half the body's [[monocyte]]s so that upon injury they can migrate to the injured tissue and transform into [[dendritic cell]]s and [[macrophage]]s and so assist [[wound healing]].<ref name="Swirski"/>


===Decreased function===
==Effects of removal==
{{See also|Asplenia}}
{{See also|Asplenia|Hyposplenia}}
Asplenia refers to a non-functioning spleen, which may be congenital or due to surgical removal
Surgical removal causes:<ref name="Jia"/>
Surgical removal causes:<ref name="Jia"/>


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A 28-year follow-up of 740 veterans of [[World War II]] who had their spleens removed on the battlefield found that those who had been [[splenectomy|splenectomize]]d showed a significant excess of mortality from [[pneumonia]] (6 rather than the expected 1.3) and a significant excess of mortality from [[ischemic heart disease]] (4.1 rather than the expected 3) but not from other conditions.<ref>{{Cite journal|pmid=69206|doi=10.1016/S0140-6736(77)90132-5|title=Splenectomy and Subsequent Mortality in Veterans of the 1939-45 War|year=1977|last1=Dennis Robinette|first1=C.|last2=Fraumeni|first2=Josephf.|journal=The Lancet|volume=310|issue=8029|pages=127–9}}</ref>
A 28-year follow-up of 740 veterans of [[World War II]] who had their spleens removed on the battlefield found that those who had been [[splenectomy|splenectomize]]d showed a significant excess of mortality from [[pneumonia]] (6 rather than the expected 1.3) and a significant excess of mortality from [[ischemic heart disease]] (4.1 rather than the expected 3) but not from other conditions.<ref>{{Cite journal|pmid=69206|doi=10.1016/S0140-6736(77)90132-5|title=Splenectomy and Subsequent Mortality in Veterans of the 1939-45 War|year=1977|last1=Dennis Robinette|first1=C.|last2=Fraumeni|first2=Josephf.|journal=The Lancet|volume=310|issue=8029|pages=127–9}}</ref>


==Clinical relevance==
==Disorders==
{{Main|Splenic disease}}
{{Main|Splenic disease}}
Disorders include [[splenomegaly]], where the spleen is enlarged for various reasons, such as [[cancer]], specifically [[blood]]-based [[leukemias]], and [[asplenia]], where the spleen is not present or functions abnormally.
Disorders include [[splenomegaly]], where the spleen is enlarged for various reasons, such as [[cancer]], specifically [[blood]]-based [[leukemias]], and [[asplenia]], where the spleen is not present or functions abnormally.
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[[trauma (medicine)|Traumas]], such as a [[motor vehicle accident]], can cause [[ruptured spleen|rupture of the spleen]], which is a situation requiring [[medical emergency|immediate medical attention]].
[[trauma (medicine)|Traumas]], such as a [[motor vehicle accident]], can cause [[ruptured spleen|rupture of the spleen]], which is a situation requiring [[medical emergency|immediate medical attention]].


==Society and culture==
==Etymology and cultural views==<!-- This section is linked from [[Gabriel Fauré]] -->
The word '''spleen''' comes from the [[Greek language|Greek]] {{lang|grc|σπλήν}} (''splḗn''), and is the idiomatic equivalent of the heart in English, i.e. to be good-spleened ({{lang|grc|εὔσπλαγχνος}}, ''eúsplankhnos'') means to be good-hearted or compassionate.<ref>Robertson's Word Pictures of the New Testament, commentary on 1 Peter 3:8</ref>
The word '''spleen''' comes from the [[Greek language|Greek]] {{lang|grc|σπλήν}} (''splḗn''), and is the idiomatic equivalent of the heart in English, i.e. to be good-spleened ({{lang|grc|εὔσπλαγχνος}}, ''eúsplankhnos'') means to be good-hearted or compassionate.<ref>Robertson's Word Pictures of the New Testament, commentary on 1 Peter 3:8</ref>


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The connection between ''spleen'' (the organ) and ''[[melancholy]]'' (the temperament) comes from the [[The four humours|humoral medicine]] of the [[ancient Greeks]]. One of the humours (body fluid) was the black [[Bile (biology)|bile]], secreted by the spleen organ and associated with melancholy. In contrast, the [[Talmud]] (tractate Berachoth 61b) refers to the spleen as the organ of [[laughter]] while possibly suggesting a link with the [[Humourism|humoral]] view of the organ. In eighteenth- and nineteenth-century England, women in bad humor were said to be afflicted by the spleen, or the vapours of the spleen. In modern English, "to vent one's spleen" means to vent one's [[anger]], e.g. by shouting, and can be applied to both males and females. Similarly, the English term "[[wikt:splenetic|splenetic]]" is used to describe a person in a foul mood.
The connection between ''spleen'' (the organ) and ''[[melancholy]]'' (the temperament) comes from the [[The four humours|humoral medicine]] of the [[ancient Greeks]]. One of the humours (body fluid) was the black [[Bile (biology)|bile]], secreted by the spleen organ and associated with melancholy. In contrast, the [[Talmud]] (tractate Berachoth 61b) refers to the spleen as the organ of [[laughter]] while possibly suggesting a link with the [[Humourism|humoral]] view of the organ. In eighteenth- and nineteenth-century England, women in bad humor were said to be afflicted by the spleen, or the vapours of the spleen. In modern English, "to vent one's spleen" means to vent one's [[anger]], e.g. by shouting, and can be applied to both males and females. Similarly, the English term "[[wikt:splenetic|splenetic]]" is used to describe a person in a foul mood.


==In animals==
==Variation among vertebrates==
In [[cartilaginous fish|cartilaginous]] and [[ray-finned fish]] it consists primarily of red pulp and is normally a somewhat elongated organ as it actually lies inside the [[serosa]]l lining of the [[intestine]]. In many [[amphibian]]s, especially [[frog]]s, it takes on the more rounded form and there is often a greater quantity of white pulp.<ref name=VB>{{cite book |author=Romer, Alfred Sherwood|author2=Parsons, Thomas S.|year=1977 |title=The Vertebrate Body |publisher=Holt-Saunders International |location= Philadelphia |pages= 410–411|isbn= 0-03-910284-X}}</ref>
In [[cartilaginous fish|cartilaginous]] and [[ray-finned fish]] it consists primarily of red pulp and is normally a somewhat elongated organ as it actually lies inside the [[serosa]]l lining of the [[intestine]]. In many [[amphibian]]s, especially [[frog]]s, it takes on the more rounded form and there is often a greater quantity of white pulp.<ref name=VB>{{cite book |author=Romer, Alfred Sherwood|author2=Parsons, Thomas S.|year=1977 |title=The Vertebrate Body |publisher=Holt-Saunders International |location= Philadelphia |pages= 410–411|isbn= 0-03-910284-X}}</ref>


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==See also==
==See also==
{{Anatomy-terms}}
* [[Marginal zone]]
* [[Marginal zone]]


==References==
==References==
{{Reflist|30em}}
{{Reflist|2}}


==External links==
==External links==

Revision as of 07:49, 22 December 2013

Spleen
Spleen
Laparoscopic view of a horse's spleen (the purple and grey mottled organ)
Details
PrecursorMesenchyme of dorsal mesogastrium
ArterySplenic artery
VeinSplenic vein
NerveSplenic plexus
Identifiers
LatinLien (Greek: Splen)
MeSHD013154
TA98A13.2.01.001
TA25159
FMA7196
Anatomical terminology

The spleen (from Greek σπλήνsplḗn[1]) is an organ found in virtually all vertebrate animals. Similar in structure to a large lymph node, it acts primarily as a blood filter. It is possible to remove the spleen without jeopardizing life. The spleen plays important roles in regard to red blood cells (also referred to as erythrocytes) and the immune system.[2] It removes old red blood cells and holds a reserve of blood, which can be valuable in case of hemorrhagic shock, and also recycles iron. As a part of the mononuclear phagocyte system, it metabolizes hemoglobin removed from senescent erythrocytes. The globin portion of hemoglobin is degraded to its constitutive amino acids, and the heme portion is metabolized to bilirubin, which is removed in the liver.[3] The spleen synthesizes antibodies in its white pulp and removes antibody-coated bacteria and antibody-coated blood cells by way of blood and lymph node circulation. A study published in 2009 using mice found that the spleen contains, in its reserve, half of the body's monocytes within the red pulp.[4] These monocytes, upon moving to injured tissue (such as the heart), turn into dendritic cells and macrophages while promoting tissue healing.[4][5][6] The spleen is a center of activity of the reticuloendothelial system and can be considered analogous to a large lymph node, as its absence causes a predisposition to certain infections.[7]

In humans, the spleen is brownish in color and is located in the left upper quadrant of the abdomen.[3][8]

Structure

The spleen, in healthy adult humans, is approximately 27 centimetres (11 in) to 14 centimetres (5.5 in) in length. It usually weighs between 150 grams (5.3 oz)[9] and 200 grams (7.1 oz).[10] An easy way to remember the anatomy of the spleen is the 1×3×5×7×9×11 rule. The spleen is 1" by 3" by 5", weighs approximately 7 oz, and lies between the 9th and 11th ribs on the left hand side.

Like the thymus, the spleen possesses only efferent lymphatic vessels. The spleen is part of the lymphatic system. Both the short gastric arteries and the splenic artery supply it with blood.[11]

The germinal centers are supplied by arterioles called penicilliary radicles.[12]

The spleen is unique in respect to its development within the gut. While most of the gut viscera are endodermally derived (with the exception of the neural-crest derived suprarenal gland), the spleen is derived from mesenchymal tissue.[13] Specifically, the spleen forms within, and from, the dorsal mesentery. However, it still shares the same blood supply—the celiac trunk—as the foregut organs.

Function

Micrograph of splenic tissue showing the red pulp (red), white pulp (blue) and a thickened inflamed capusule (mostly pink - top of image). H&E stain.
Area Function Composition
red pulp Mechanical filtration of red blood cells. In mice: Reserve of monocytes[4]
white pulp Active immune response through humoral and cell-mediated pathways. Composed of nodules, called Malpighian corpuscles. These are composed of:

Other functions of the spleen are less prominent, especially in the healthy adult:

  • Production of opsonins, properdin, and tuftsin.
  • Creation of red blood cells. While the bone marrow is the primary site of hematopoiesis in the adult, the spleen has important hematopoietic functions up until the fifth month of gestation. After birth, erythropoietic functions cease, except in some hematologic disorders. As a major lymphoid organ and a central player in the reticuloendothelial system, the spleen retains the ability to produce lymphocytes and, as such, remains an hematopoietic organ.
  • Storage of red blood cells, lymphocytes and other formed elements. In horses, roughly 30% of the red blood cells are stored there. The red blood cells can be released when needed.[14] In humans, up to a cup (236.5 ml) of red blood cells can be held in the spleen and released in cases of hypovolemia.[15] It can store platelets in case of an emergency. Up to a quarter of lymphocytes can be stored in the spleen at any one time.
  • In mice, the spleen stores half the body's monocytes so that upon injury they can migrate to the injured tissue and transform into dendritic cells and macrophages and so assist wound healing.[4]

Decreased function

Asplenia refers to a non-functioning spleen, which may be congenital or due to surgical removal Surgical removal causes:[5]

  • modest increases in circulating white blood cells and platelets,
  • diminished responsiveness to some vaccines,
  • increased susceptibility to infection by bacteria and protozoa; in particular, there is an increased risk of sepsis from polysaccharide encapsulated bacteria. Encapsulated bacteria inhibit binding of complement or prevent complement assembled on the capsule from interacting with macrophage receptors. Natural antibodies are required for phagocytosis, which are immunoglobulins that facilitate phagocytosis either directly or by complement deposition on the capsule. They are produced by IgM memory B cells in the marginal zone of the spleen.[16][17] Splenectomy greatly diminishes the frequency of memory B cells.[18]

A 28-year follow-up of 740 veterans of World War II who had their spleens removed on the battlefield found that those who had been splenectomized showed a significant excess of mortality from pneumonia (6 rather than the expected 1.3) and a significant excess of mortality from ischemic heart disease (4.1 rather than the expected 3) but not from other conditions.[19]

Clinical relevance

Disorders include splenomegaly, where the spleen is enlarged for various reasons, such as cancer, specifically blood-based leukemias, and asplenia, where the spleen is not present or functions abnormally.

Traumas, such as a motor vehicle accident, can cause rupture of the spleen, which is a situation requiring immediate medical attention.

Society and culture

The word spleen comes from the Greek σπλήν (splḗn), and is the idiomatic equivalent of the heart in English, i.e. to be good-spleened (εὔσπλαγχνος, eúsplankhnos) means to be good-hearted or compassionate.[20]

In English the word spleen was customary during the period of the 18th century. Authors like Richard Blackmore or George Cheyne employed it to characterise the hypochondriacal and hysterical affections.[21][22] William Shakespeare, in Julius Caesar uses the spleen to describe Cassius' irritable nature.

Must I observe you? must I stand and crouch
Under your testy humour? By the gods
You shall digest the venom of your spleen,
Though it do split you; for, from this day forth,
I'll use you for my mirth, yea, for my laughter,
When you are waspish.[23]

In French, "splénétique" refers to a state of pensive sadness or melancholy. It has been popularized by the poet Charles Baudelaire (1821–1867) but was already used before in particular to the Romantic literature (19th century). The word for the organ is "rate".

In Turkish, the slang phrase "dalağını sikeyim (fuck your spleen)" is widely used to express anger or disappointment.

The connection between spleen (the organ) and melancholy (the temperament) comes from the humoral medicine of the ancient Greeks. One of the humours (body fluid) was the black bile, secreted by the spleen organ and associated with melancholy. In contrast, the Talmud (tractate Berachoth 61b) refers to the spleen as the organ of laughter while possibly suggesting a link with the humoral view of the organ. In eighteenth- and nineteenth-century England, women in bad humor were said to be afflicted by the spleen, or the vapours of the spleen. In modern English, "to vent one's spleen" means to vent one's anger, e.g. by shouting, and can be applied to both males and females. Similarly, the English term "splenetic" is used to describe a person in a foul mood.

In animals

In cartilaginous and ray-finned fish it consists primarily of red pulp and is normally a somewhat elongated organ as it actually lies inside the serosal lining of the intestine. In many amphibians, especially frogs, it takes on the more rounded form and there is often a greater quantity of white pulp.[24]

In reptiles, birds, and mammals, white pulp is always relatively plentiful, and in the latter two groups, the spleen is typically rounded, although it adjusts its shape somewhat to the arrangement of the surrounding organs. In the great majority of vertebrates, the spleen continues to produce red blood cells throughout life; it is only in mammals that this function is lost in adults. Many mammals have tiny spleen-like structures known as haemal nodes throughout the body that are presumed to have the same function as the spleen.[24] The spleens of aquatic mammals differ in some ways from those of fully land-dwelling mammals. In general, they are bluish in colour. In cetaceans and manatees they tend to be quite small, but in deep diving pinnipeds, they can be quite massive, due to their function of storing red blood cells.

The only vertebrates lacking a spleen are the lampreys and hagfishes. Even in these animals, there is a diffuse layer of haematopoeitic tissue within the gut wall, which has a similar structure to red pulp and is presumed to be homologous with the spleen of higher vertebrates.[24]

Gallery

See also

References

  1. ^ σπλήν, Henry George Liddell, Robert Scott, A Greek-English Lexicon, on Perseus Digital Library
  2. ^ Spleen, Internet Encyclopedia of Science
  3. ^ a b Mebius, RE; Kraal, G (2005). "Structure and function of the spleen". Nature reviews. Immunology. 5 (8): 606–16. doi:10.1038/nri1669. PMID 16056254.
  4. ^ a b c d Swirski, FK; Nahrendorf, M; Etzrodt, M; Wildgruber, M; Cortez-Retamozo, V; Panizzi, P; Figueiredo, JL; Kohler, RH; Chudnovskiy, A; Waterman, P; Aikawa, E; Mempel, TR; Libby, P; Weissleder, R; Pittet, MJ (2009). "Identification of splenic reservoir monocytes and their deployment to inflammatory sites". Science. 325 (5940): 612–6. doi:10.1126/science.1175202. PMC 2803111. PMID 19644120.
  5. ^ a b Jia, T; Pamer, EG (2009). "Immunology. Dispensable but not irrelevant". Science. 325 (5940): 549–50. doi:10.1126/science.1178329. PMC 2917045. PMID 19644100.
  6. ^ Finally, the Spleen Gets Some Respect By NATALIE ANGIER, The New York Times, August 3, 2009
  7. ^ Brender, MD, Erin (2005-11-23). "Spleen Patient Page" (PDF). Journal of the American Medical Association. 294 (20). American Medical Association: 2660. doi:10.1001/jama.294.20.2660. PMID 16304080. Retrieved 2008-03-20. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  8. ^ Loscalzo, Joseph; Fauci, Anthony S.; Braunwald, Eugene; Dennis L. Kasper; Hauser, Stephen L; Longo, Dan L. (2008). Harrison's principles of internal medicine. McGraw-Hill Medical. ISBN 978-0-07-146633-2.{{cite book}}: CS1 maint: multiple names: authors list (link)
  9. ^ eMedicine > Splenomegaly Author: David J Draper. Coauthor(s): Ronald A Sacher, Emmanuel N Dessypris, Lewis J Kaplan. Updated: Oct 4, 2009
  10. ^ Spielmann, Audrey L. (1 January 2005). "Sonographic Evaluation of Spleen Size in Tall Healthy Athletes". American Journal of Roentgenology. 2005 (184). American Roentgen Ray Society: 45–49. doi:10.2214/ajr.184.1.01840045. PMID 15615949. Retrieved 2008-09-09. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  11. ^ Blackbourne, Lorne H (2008-04-01). Surgical recall. Lippincott Williams & Wilkins. p. 259. ISBN 978-0-7817-7076-7.
  12. ^ "Penicilliary radicles". Medical-dictionary.thefreedictionary.com. Retrieved 2011-04-03.
  13. ^ Vellguth, Swantje (1985). "The development of the human spleen". Cell and Tissue Research. 242 (3). Springer Berlin / Heidelberg: 579–592. doi:10.1007/BF00225424. Retrieved 2009-02-14. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  14. ^ Carey, Bjorn (May 5, 2006). "Horse science: What makes a Derby winner - Spleen acts as a 'natural blood doper,' scientist says". MSNBC.com. Retrieved 2006-05-09.
  15. ^ "Spleen: Information, Surgery and Functions". Childrens Hospital of Pittsburgh - Chp.edu. 2010-11-17. Retrieved 2011-04-03.
  16. ^ Di Sabatino, A (2011 Jul 2). "Post-splenectomy and hyposplenic states". Lancet. 378 (9785): 86–97. doi:10.1016/S0140-6736(10)61493-6. PMID 21474172. {{cite journal}}: Check date values in: |date= (help); Unknown parameter |coauthors= ignored (|author= suggested) (help)
  17. ^ Carsetti, R (2004 Feb). "Peripheral development of B cells in mouse and man". Immunological reviews. 197: 179–91. doi:10.1111/j.0105-2896.2004.0109.x. PMID 14962195. {{cite journal}}: Check date values in: |date= (help); Unknown parameter |coauthors= ignored (|author= suggested) (help)
  18. ^ Kruetzmann, S (2003 Apr 7). "Human immunoglobulin M memory B cells controlling Streptococcus pneumoniae infections are generated in the spleen". The Journal of experimental medicine. 197 (7): 939–45. doi:10.1084/jem.20022020. PMC 2193885. PMID 12682112. {{cite journal}}: Check date values in: |date= (help); Unknown parameter |coauthors= ignored (|author= suggested) (help)
  19. ^ Dennis Robinette, C.; Fraumeni, Josephf. (1977). "Splenectomy and Subsequent Mortality in Veterans of the 1939-45 War". The Lancet. 310 (8029): 127–9. doi:10.1016/S0140-6736(77)90132-5. PMID 69206.
  20. ^ Robertson's Word Pictures of the New Testament, commentary on 1 Peter 3:8
  21. ^ Cheyne, George: The English Malady; or, A Treatise of Nervous Diseases of All Kinds, as Spleen, Vapours, Lowness of Spirits, Hypochondriacal and Hysterical Distempers with the Author's own Case at large, Dublin, 1733. Facsimile ed., ed. Eric T. Carlson, M.D., 1976, Scholars' Facsimiles & Reprints, ISBN 978-0-8201-1281-7;
  22. ^ Blackmore, Richard: Treatise of the spleen and vapors. London, 1725
  23. ^ Julius Caesar by William Shakespeare Act 4:1
  24. ^ a b c Romer, Alfred Sherwood; Parsons, Thomas S. (1977). The Vertebrate Body. Philadelphia: Holt-Saunders International. pp. 410–411. ISBN 0-03-910284-X.

External links

Template:Animal anatomy