Editing Lymph node (section)

=== Location ===
{{See also|List of lymph nodes of the human body}}
Lymph nodes are present throughout the body, are more concentrated near and within the trunk, and are divided into groups.<ref name="Grays2016" /> There are about 450 lymph nodes in the adult.<ref name="Grays2016" /> Some lymph nodes can be felt when enlarged (and occasionally when not), such as the [[axillary lymph nodes]] under the arm, the [[cervical lymph nodes]] of the head and neck and the [[inguinal lymph nodes]] near the groin crease. Most lymph nodes lie within the trunk adjacent to other major structures in the body - such as the [[paraaortic lymph nodes]] and the [[tracheobronchial lymph nodes]]. The lymphatic drainage patterns are different from person to person and even asymmetrical on each side of the same body.<ref>{{Cite web|last=Themes|first=U. F. O.|date=2018-01-06|title=Lymphatic Anatomy and Clinical Implications|url=https://entokey.com/lymphatic-anatomy-and-clinical-implications/|access-date=2020-09-21|website=Ento Key|language=en-US}}</ref><ref>{{Cite journal |last1=Pan |first1=Wei-Ren |last2=Wang |first2=De-Guang |date=2013 |title=Historical review of lymphatic studies in the head and neck |url=https://www.woundsinternational.com/uploads/resources/content_11242.pdf |journal=Journal of Lymphoedema |language=en |publisher=WoundsGroup |volume=8 |access-date=21 September 2020 |archive-date=30 July 2021 |archive-url=https://web.archive.org/web/20210730072220/https://www.woundsinternational.com/uploads/resources/content_11242.pdf |url-status=dead }}</ref>

There are no lymph nodes in the [[central nervous system]], which is separated from the body by the [[blood–brain barrier]]. Lymph from the [[meningeal lymphatic vessels]] in the CNS drains to the [[deep cervical lymph node]]s.<ref name="Dupont">{{cite journal | vauthors = Dupont G, Schmidt C, Yilmaz E, Oskouian RJ, Macchi V, de Caro R, Tubbs RS | title = Our current understanding of the lymphatics of the brain and spinal cord | journal = Clinical Anatomy | volume = 32 | issue = 1 | pages = 117–121 | date = January 2019 | pmid = 30362622 | doi = 10.1002/ca.23308 | s2cid = 53102520 | doi-access =  }}</ref> However, the CNS does innervate lymph node by [[Sympathetic nervous system|sympathetic nerves]].  These regulate [[Lymphocyte|lymphocyte proliferation and migration]], [[Antibody|antibody secretion]], [[Blood|blood perfusion]], and [[Cytokine|inflammatory cytokine production]].<ref name="z657">{{cite journal |last1=Cleypool |first1=Cindy G. J. |last2=Mackaaij |first2=Claire |last3=Lotgerink Bruinenberg |first3=Dyonne |last4=Schurink |first4=Bernadette |last5=Bleys |first5=Ronald L. A. W. |date=2021 |title=Sympathetic nerve distribution in human lymph nodes |journal=Journal of Anatomy |publisher=Wiley |volume=239 |issue=2 |pages=282–289 |doi=10.1111/joa.13422 |issn=0021-8782 |doi-access=free|pmid=33677834 |pmc=8273593 }}</ref>