Rexed laminae
{{Short description|Layers of grey matter in the spinal cord}}
Image:Medulla spinalis - Substantia grisea - English.svg
Image:Spinalcord trirev rexedlamina.svg
{{wiktionary|Rexed lamina}}
The Rexed laminae (singular: Rexed lamina) comprise a system of ten layers of grey matter (I–X), identified in the early 1950s by Bror Rexed to label portions of the grey columns of the spinal cord.{{cite journal | vauthors = Rexed B | title = The cytoarchitectonic organization of the spinal cord in the cat | journal = The Journal of Comparative Neurology | volume = 96 | issue = 3 | pages = 414–95 | date = June 1952 | pmid = 14946260 | doi = 10.1002/cne.900960303 | s2cid = 42584106 }}{{cite journal | vauthors = Rexed B | title = A cytoarchitectonic atlas of the spinal cord in the cat | journal = The Journal of Comparative Neurology | volume = 100 | issue = 2 | pages = 297–379 | date = April 1954 | pmid = 13163236 | doi = 10.1002/cne.901000205 | s2cid = 40517545 }}
Similar to Brodmann areas, they are defined by their cellular structure rather than by their location, but the location still remains reasonably consistent.{{citation needed|date=July 2015}}
Laminae
- Posterior grey column: I–VI
- Lamina I: marginal nucleus of spinal cord or posteromarginal nucleus
- Lamina II: substantia gelatinosa of Rolando
- Laminae III and IV: nucleus proprius
- Lamina V: Neck of the dorsal horn. Neurons within lamina V are mainly involved in processing sensory afferent stimuli from cutaneous, muscle and joint mechanical nociceptors as well as visceral nociceptors. This layer is home to wide dynamic range tract neurons, interneurons and propriospinal neurons. Viscerosomatic pain signal convergence often occurs in this lamina due to the presence of wide dynamic range tract neurons resulting in pain referral.{{cite book|last1=Darby|first1=Susan A. | last2 = Cramer | first2 = Gregory D. | name-list-style = vanc |title=Clinical Anatomy of the Spine, Spinal Cord and ANS|date=2013|publisher=Mosby|location=Saint Louis, MO, USA|isbn=978-0323079549|pages=341–413}}
- Lamina VI: Base of the dorsal horn. No nociceptive input occurs here, instead this lamina receives input from large-diameter fibres innervating muscles and joints and from muscle spindles which are sensitive to innocuous joint movement and muscle stretch to feed forward this information to the cerebellum where it can modulate muscle tone accordingly.{{cite book|last1=Kandel|first1=Eric R. | last2 =Schwartz | first2 = James H. | name-list-style = vanc |title=Principles of Neural Science|date=2013|publisher=McGraw-Hill Group|location=New York City, NY, USA|isbn=978-0-07-139011-8|pages=535|edition=5th }}
- Lateral grey column: VII and X
- Lamina VII: intermediomedial nucleus, intermediolateral nucleus, posterior thoracic nucleus in the thoracic and upper lumbar region{{cite book | last = Blumenfeld | first = Hal | name-list-style = vanc | year = 2010 | title = Neuroanatomy through Clinical Cases | location = Sunderland, MA | publisher = Sinauer Associates }}
- Lamina X: an area of grey matter – the grey commissure surrounding the central canal. This region also serves to connect the anterior and posterior grey columns.{{cite book |last1=Carpenter |first1=Malcolm B. |title=Core text of neuroanatomy |date=1985 |publisher=Williams & Wilkins |location=Baltimore |isbn=0683014552 |pages=61–68 |edition=3rd.}} Rexed never described this as lamina X but as area X.{{cite book |last1=Haines |first1=Duane |title=Fundamental neuroscience for basic and clinical applications |date=2018 |publisher=Elsevier |location=Philadelphia, PA |isbn=9780323396325 |page=141 |edition=Fifth}}
- Anterior grey column: VIII–IX
- Lamina VIII: motor interneurons
- Lamina IX: hypaxial (body wall muscles), lateral (in limb regions) and medial (back muscles) motor neurons, also phrenic and spinal accessory nuclei at cervical levels, and Onuf's nucleus in the sacral region