Editing Nerve (section)

==Clinical significance==
[[Image:Prostatic adenocarcinoma with perineural invasion.JPG|thumb|right|[[Micrograph]] demonstrating [[perineural invasion]] of [[prostate cancer]]. [[H&E stain]].]]
[[Neurology|Neurologists]] usually diagnose disorders of nerves by a [[physical examination]], including the testing of [[reflex]]es, [[walking]] and other directed movements, [[muscle weakness]], [[proprioception]], and the sense of [[Somatosensory system|touch]]. This initial exam can be followed with tests such as [[nerve conduction study]], [[electromyography]] (EMG), and [[computed tomography]] (CT).<ref name="Weinberg">{{cite book |author=Weinberg |title=Normal computed tomography of the brain |page=109}}{{full citation needed|date=September 2022}}</ref>

Nerves can be damaged by physical injury as well as conditions like [[carpal tunnel syndrome]] (CTS) and [[repetitive strain injury]]. [[Autoimmune disease]]s such as [[Guillain–Barré syndrome]], [[neurodegenerative disease]]s, [[polyneuropathy]], infection, [[neuritis]], [[diabetes]], or failure of the blood vessels surrounding the nerve all cause [[Nerve injury|nerve damage]], which can vary in severity. A [[pinched nerve]] occurs when pressure is placed on a nerve, usually from swelling due to an injury, or pregnancy and can result in [[pain]], weakness, numbness or paralysis, an example being CTS. Symptoms can be felt in areas far from the actual site of damage, a phenomenon called [[referred pain]]. Referred pain can happen when the damage causes altered signalling to other areas.

[[Cancer]] can spread by invading the spaces around nerves. This is particularly common in [[head and neck cancer]], [[prostate cancer]] and [[colorectal cancer]]. [[Multiple sclerosis]] is a disease associated with extensive nerve damage. It occurs when the [[macrophage]]s of an individual's own immune system damage the myelin sheaths that insulate the axon of the nerve.