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{{Infobox Vein |
{{Infobox vein
Name = {{PAGENAME}} |
| Name = Rectal venous plexus
| Latin = plexus venosus rectalis,<ref>{{Cite web |title=Anatonomina |url=http://www.terminologia-anatomica.org/en/Terms/Occurence/4822 |access-date=2023-07-08 |website=www.terminologia-anatomica.org}}</ref><br>plexus haemorrhoidalis
Latin = plexus venosus rectalis, plexus haemorrhoidalis |
| Image = Gray587.png
GraySubject = 173 |
| Caption = Scheme of the anastomosis of the veins of the [[rectum]].
GrayPage = 676 |
Image = Gray587.png |
| Image2 = Gray585.png
Caption = Scheme of the anastomosis of the veins of the [[rectum]]. |
| Caption2 = The veins of the right half of the male [[pelvis]].
⚫
| DrainsFrom =
Image2 = Gray585.png |
⚫
| Source =
Caption2 = The veins of the right half of the male [[pelvis]]. |
| DrainsTo = [[Superior rectal vein]],<br>[[Middle rectal vein|middle rectal vein(s)]],<br>[[inferior rectal veins]]
⚫
DrainsFrom = |
Source = |
| Artery =
DrainsTo = [[superior rectal vein]] |
⚫
Artery = |
MeshName = |
MeshNumber = |
DorlandsPre = p_24 |
DorlandsSuf = 12648664 |
}}
}}
The '''rectal venous plexus''' (or '''hemorrhoidal plexus'''<ref>{{Cite web |title=plexus venosus rectalis |url=https://medical-dictionary.thefreedictionary.com/plexus+venosus+rectalis |access-date=2023-07-08 |website=TheFreeDictionary.com}}</ref>) is the [[venous plexus]] surrounding the [[rectum]].<ref name=":224">{{Cite book |last=Standring |first=Susan |url=https://www.worldcat.org/oclc/1201341621 |title=Gray's Anatomy: The Anatomical Basis of Clinical Practice |year=2020 |isbn=978-0-7020-7707-4 |edition=42th |location=New York |pages=1198 |oclc=1201341621}}</ref> It consists of an internal and an external rectal plexus.<ref name=":0">{{Cite book |last=Moore |first=Keith L. |title=Clinically Oriented Anatomy |last2=Dalley |first2=Arthur F. |last3=Agur |first3=Anne M. R. |date= |publisher=Wolters Kluwer |year=2018 |isbn=978-1-4963-4721-3 |edition=8th |location=}}</ref>{{Rp|page=598}}'''<ref name=":022" />{{Rp|page=294}}''' It is drained by the superior, middle, and inferior rectal veins. It forms a [[Portosystemic anastomoses|portosystemic (portocaval) anastomosis]].<ref name=":224" /> This allows rectally administered medications to bypass [[First pass effect|first pass metabolism]].{{Citation needed|date=July 2023}}
The '''hemorrhoidal plexus''' (or '''rectal venous plexus''') surrounds the [[rectum]], and communicates in front with the [[vesical venous plexus]] in the male, and the [[uterovaginal plexus]] in the female.


Despite the inclusion of the term "rectal" into the name, the venous plexus is positionally, functionally, and clinically primarily related to the [[anal canal]].<ref name="Moore-20112">{{cite book |last1=Moore |first1=Keith L. |title=Essential Clinical Anatomy |last2=Dalley |first2=Arthur F. |last3=Agur |first3=Anne M. R. |publisher=Lippincott Williams & Wilkins |year=2017 |isbn=978-1496347213 |edition=6th |page= |pages=598}}</ref>
A free communication between the portal and systemic venous systems is established through the hemorrhoidal plexus.


==Parts==
==Anatomy==
The rectal venous plexus consists of an external rectal plexus<ref name=":0" />{{Rp|page=598}}'''<ref name=":022">{{Cite book |last=Sinnatamby |first=Chummy S. |title=Last's Anatomy |vauthors= |publisher= |year=2011 |isbn=978-0-7295-3752-0 |edition=12th |pages=}}</ref>{{Rp|page=294}}''' that is situated outside to the muscular wall,<ref name=":224" /><ref name=":0" />{{Rp|page=598}}'''<ref name=":022" />{{Rp|page=294}}''' and an internal rectal plexus<ref name=":0" />{{Rp|page=598}}'''<ref name=":022" />{{Rp|page=294}}''' that is situated in the [[submucosa]]<ref name=":022" />{{Rp|page=294}}/deep to the mucosa<ref name=":224" /><ref name=":0" />{{Rp|page=598}} of the rectum and proximal [[anal canal]]<ref name=":224" /> at the [[anorectal junction]].<ref name=":0" />{{Rp|page=598}}
It consists of two parts, an internal in the submucosa, and an external outside the muscular coat.


===Internal plexus===
===Internal rectal plexus===
The internal plexus presents a series of dilated pouches which are arranged in a circle around the tube, immediately above the anal orifice, and are connected by transverse branches.
The internal plexus presents a series of dilated pouches which are arranged in a circle around the tube, immediately above the anal orifice, and are connected by transverse branches.{{Citation needed|date=July 2023}}


The internal plexus (sources differ) forms'''<ref name=":0" />{{Rp|page=641}}'''/is continuous distally/inferiorly with'''<ref name=":022" />{{Rp|page=294}}''' the [[Hemorrhoid|hemorrhoids]] (the vascular cushions of the [[anal canal]]).'''<ref name=":022" />{{Rp|page=294}}<ref name=":0" />{{Rp|page=641}}'''
This internal plexus is also known in some medical communities as the Irving plexus.


===External plexus===
==== Venous drainage ====
* The lower part of the external plexus is drained by the [[inferior rectal veins]] into the [[internal pudendal vein]]
According to the 42nd edition of ''[[Gray's Anatomy]]'' (2020), the internal rectal plexus is drained mostly by the [[superior rectal vein]] (→[[inferior mesenteric vein]]→[[splenic vein]]→[[portal vein|hepatic portal vein]]).<ref name=":224" />


According to the 8th edition of ''Clinically Oriented Anatomy'' (2017), the internal rectal plexus is drains mostly into the [[superior rectal vein]] superior/proximal to the [[pectinate line]], and into the [[inferior rectal veins]] (→[[internal pudendal vein]]→[[internal iliac vein]]→[[common iliac vein]]→[[inferior vena cava]]) around the margin of the [[external anal sphincter]] inferior/distal to the pectinate line.<ref name=":0" />{{Rp|page=641}}
* The middle part of the external plexus is drained by the [[middle rectal vein]] which joins the [[internal iliac vein]].


===External rectal plexus===
* The upper part of the external plexus is drained by the [[superior rectal vein]] which forms the commencement of the [[inferior mesenteric vein]], a tributary of the [[portal vein]].


==== Venous drainage ====
==Support==
* The proximal/superior part mostly drains into the [[superior rectal vein]] (→[[inferior mesenteric vein]]→[[splenic vein]]→[[portal vein|hepatic portal vein]])<ref name=":224" />
⚫
The veins of the hemorrhoidal plexus are contained in very loose, connective tissue, so that they get less support from surrounding structures than most other veins, and are less capable of resisting increased [[blood-pressure]].
* The middle part drains into [[middle rectal vein|middle rectal vein(s)]] (→[[internal iliac vein]]→[[common iliac vein]]→[[inferior vena cava]])<ref name=":224" />
* The distal/inferior part drains into [[inferior rectal veins]] (→[[internal pudendal vein]]→[[internal iliac vein]]→[[common iliac vein]]→[[inferior vena cava]])<ref name=":224" />


=== Structure ===
⚫
The veins of the hemorrhoidal plexus are contained in very loose connective tissue, so that they get less support from surrounding structures than most other veins, and are less capable of resisting increased [[blood-pressure]].{{Citation needed|date=July 2023}}

=== Anastomoses ===
The rectal venous plexus represents a [[Portosystemic anastomoses|portosystemic (portocaval) anastomosis]].<ref name=":224" />'''<ref name=":022" />'''{{Rp|page=315}} The transition from drainage into the portal system to drainage into the inferior caval system occurs in the region of the [[anal columns]].'''<ref name=":022" />'''{{Rp|page=315}}

It communicates anteriorly with the [[Uterine venous plexus|uterine]] and [[vaginal venous plexus]] in the female, and with the [[vesical venous plexus]] in the male.<ref name=":224" />

== Clinical significance ==
The internal rectal plexus may prolapse into the anal canal to form pathological '''internal haemerrhoids'''; these are often strangulated by the contraction of the anal sphincter, causing ulceration and bleeding.'''<ref name=":0" />{{Rp|page=645}}'''

The external rectal plexus may be affected by [[Blood clot|blood clots (thrombi)]], resulting in '''external haemerrhoids'''.'''<ref name=":0" />{{Rp|page=645}}'''

== References ==
{{Gray's}}
{{Gray's}}
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{{Reflist}}{{Veins}}
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{{circulatory-stub}}
{{Portal bar|Anatomy}}
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{{Veins}}
{{Authority control}}


[[Category:Veins of the torso]]
[[Category:Veins of the torso]]
[[Category:Rectum]]
[[Category:Rectum]]



[[pt:Plexo venoso retal]]
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{{circulatory-stub}}
[[ur:بالائی باسوری وریدی ضفیرہ]]

Latest revision as of 15:44, 8 May 2024

Rectal venous plexus
Scheme of the anastomosis of the veins of the rectum.
The veins of the right half of the male pelvis.
Details
Drains toSuperior rectal vein,
middle rectal vein(s),
inferior rectal veins
Identifiers
Latinplexus venosus rectalis,[1]
plexus haemorrhoidalis
TA98A12.3.10.010
TA25031
FMA18933
Anatomical terminology

The rectal venous plexus (or hemorrhoidal plexus[2]) is the venous plexus surrounding the rectum.[3] It consists of an internal and an external rectal plexus.[4]: 598 [5]: 294  It is drained by the superior, middle, and inferior rectal veins. It forms a portosystemic (portocaval) anastomosis.[3] This allows rectally administered medications to bypass first pass metabolism.[citation needed]

Despite the inclusion of the term "rectal" into the name, the venous plexus is positionally, functionally, and clinically primarily related to the anal canal.[6]

Anatomy[edit]

The rectal venous plexus consists of an external rectal plexus[4]: 598 [5]: 294  that is situated outside to the muscular wall,[3][4]: 598 [5]: 294  and an internal rectal plexus[4]: 598 [5]: 294  that is situated in the submucosa[5]: 294 /deep to the mucosa[3][4]: 598  of the rectum and proximal anal canal[3] at the anorectal junction.[4]: 598 

Internal rectal plexus[edit]

The internal plexus presents a series of dilated pouches which are arranged in a circle around the tube, immediately above the anal orifice, and are connected by transverse branches.[citation needed]

The internal plexus (sources differ) forms[4]: 641 /is continuous distally/inferiorly with[5]: 294  the hemorrhoids (the vascular cushions of the anal canal).[5]: 294 [4]: 641 

Venous drainage[edit]

According to the 42nd edition of Gray's Anatomy (2020), the internal rectal plexus is drained mostly by the superior rectal vein (→inferior mesenteric vein→splenic vein→hepatic portal vein).[3]

According to the 8th edition of Clinically Oriented Anatomy (2017), the internal rectal plexus is drains mostly into the superior rectal vein superior/proximal to the pectinate line, and into the inferior rectal veins (→internal pudendal vein→internal iliac vein→common iliac vein→inferior vena cava) around the margin of the external anal sphincter inferior/distal to the pectinate line.[4]: 641 

External rectal plexus[edit]

Venous drainage[edit]

Structure[edit]

The veins of the hemorrhoidal plexus are contained in very loose connective tissue, so that they get less support from surrounding structures than most other veins, and are less capable of resisting increased blood-pressure.[citation needed]

Anastomoses[edit]

The rectal venous plexus represents a portosystemic (portocaval) anastomosis.[3][5]: 315  The transition from drainage into the portal system to drainage into the inferior caval system occurs in the region of the anal columns.[5]: 315 

It communicates anteriorly with the uterine and vaginal venous plexus in the female, and with the vesical venous plexus in the male.[3]

Clinical significance[edit]

The internal rectal plexus may prolapse into the anal canal to form pathological internal haemerrhoids; these are often strangulated by the contraction of the anal sphincter, causing ulceration and bleeding.[4]: 645 

The external rectal plexus may be affected by blood clots (thrombi), resulting in external haemerrhoids.[4]: 645 

References[edit]

Public domain This article incorporates text in the public domain from page 676 of the 20th edition of Gray's Anatomy (1918)

  1. ^ "Anatonomina". www.terminologia-anatomica.org. Retrieved 2023-07-08.
  2. ^ "plexus venosus rectalis". TheFreeDictionary.com. Retrieved 2023-07-08.
  3. ^ a b c d e f g h i j k Standring, Susan (2020). Gray's Anatomy: The Anatomical Basis of Clinical Practice (42th ed.). New York. p. 1198. ISBN 978-0-7020-7707-4. OCLC 1201341621.{{cite book}}: CS1 maint: location missing publisher (link)
  4. ^ a b c d e f g h i j k Moore, Keith L.; Dalley, Arthur F.; Agur, Anne M. R. (2018). Clinically Oriented Anatomy (8th ed.). Wolters Kluwer. ISBN 978-1-4963-4721-3.
  5. ^ a b c d e f g h i Sinnatamby, Chummy S. (2011). Last's Anatomy (12th ed.). ISBN 978-0-7295-3752-0.
  6. ^ Moore, Keith L.; Dalley, Arthur F.; Agur, Anne M. R. (2017). Essential Clinical Anatomy (6th ed.). Lippincott Williams & Wilkins. p. 598. ISBN 978-1496347213.


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