Editing Polio (section)

==== Spinal polio ====
[[File:Polio spinal diagram-en.svg|thumb|left|The location of [[motor neuron]]s in the [[Anterior horn (spinal cord)|anterior horn cells]] of the [[spinal column]]]]

Spinal polio, the most common form of paralytic poliomyelitis, results from viral invasion of the motor neurons of the [[Anterior horn (spinal cord)|anterior horn cells]], or the [[ventral]] (front) [[grey matter]] section in the [[spinal column]], which are responsible for movement of the muscles, including those of the [[torso|trunk]], [[limb (anatomy)|limbs]], and the [[intercostal muscle]]s.<ref name= Henry1>{{cite book |vauthors=Frauenthal HW, Manning JV | title = Manual of infantile paralysis, with modern methods of treatment.| publisher = Philadelphia Davis | year = 1914| pages= [https://archive.org/details/amanualinfantil00fraugoog/page/n103 79]–101 |url= https://archive.org/details/amanualinfantil00fraugoog | oclc= 2078290}}</ref> Virus invasion causes inflammation of the nerve cells, leading to damage or destruction of motor neuron [[ganglion|ganglia]]. When spinal neurons die, [[Wallerian degeneration]] takes place, leading to weakness of those muscles formerly [[innervate]]d by the now-dead neurons.<ref>{{Cite web|url = http://phil.cdc.gov/phil/details.asp?pid=2760|title = A photomicrograph of the thoracic spinal cord depicting degenerative changes due to Polio Type III.|date = 18 March 2005|access-date = 24 January 2014|website = Public Health Image Library (PHIL)|publisher = Centers for Disease Control and Prevention| vauthors = Karp H |url-status = live|archive-url = https://web.archive.org/web/20140202193927/http://phil.cdc.gov/phil/details.asp?pid=2760|archive-date = 2 February 2014}}</ref> With the destruction of nerve cells, the muscles no longer receive signals from the brain or spinal cord; without nerve stimulation, the muscles [[atrophy]], becoming weak, floppy and poorly controlled, and finally completely paralyzed.<ref name=Henry1 /> Maximum paralysis progresses rapidly (two to four days), and usually involves fever and muscle pain. Deep [[tendon reflex]]es are also affected, and are typically absent or diminished; [[Sense|sensation]] (the ability to feel) in the paralyzed limbs, however, is not affected.<ref>{{cite web|url = https://www.cdc.gov/vaccines/pubs/surv-manual/chpt12-polio.html|title = Chapter 12: Poliomyelitis|date = 13 April 2013|access-date = 24 January 2014|website = Manual for the Surveillance of Vaccine-Preventable Diseases (5th Edition, 2012)|publisher = Centers for Disease Control and Prevention| vauthors = Wallace GS, Oberste SM |url-status = live|archive-url = https://web.archive.org/web/20140128113623/http://www.cdc.gov/vaccines/pubs/surv-manual/chpt12-polio.html|archive-date = 28 January 2014}}</ref>

The extent of spinal paralysis depends on the region of the cord affected, which may be [[neck|cervical]], [[human thorax|thoracic]], or [[lumbar]].<ref name=Guide>{{cite book |title=Professional Guide to Diseases (Professional Guide Series) |publisher=Lippincott Williams & Wilkins |location=Hagerstown, MD |year=2005 |pages=[https://archive.org/details/professionalguid0000unse_o7n1/page/243 243–45] |isbn=978-1-58255-370-2 |url=https://archive.org/details/professionalguid0000unse_o7n1/page/243 }}</ref> The virus may affect muscles on both sides of the body, but more often the paralysis is [[Asymmetry|asymmetrical]].<ref name=Baron /> Any [[Limb (anatomy)|limb]] or combination of limbs may be affected&nbsp;– one leg, one arm, or both legs and both arms.  Paralysis is often more severe [[Anatomical terms of location#Proximal distal|proximally]] (where the limb joins the body) than [[Anatomical terms of location#Proximal distalDistally|distally]] (the [[fingertip]]s and [[toe]]s).<ref name=Baron />