Editing Plantar reflex (section)

==Interpretation==
[[File:Babinski-newborn.jpg|thumb|right|240px|Babinski's sign in a healthy newborn]]

The Babinski sign can indicate [[upper motor neuron lesion]] constituting damage to the [[corticospinal tract]]. Occasionally, a pathological plantar reflex  is the first and only indication of a serious disease process and a clearly abnormal plantar reflex often prompts detailed [[neurology|neurological]] investigations, including [[Computed tomography|CT scanning]] of the brain or [[Magnetic resonance imaging|MRI]] of the spine, as well as [[lumbar puncture]] for the study of [[cerebrospinal fluid]].

The phrase "negative Babinski sign" is sometimes used for the normal flexor plantar response.<ref name="Larner2006">{{cite book|last=Larner|first=A. J.|title=A Dictionary of Neurological Signs|url=https://books.google.com/books?id=lmk6vxPeE7sC&pg=PA50|year=2006|publisher=Springer|isbn=978-0-387-26214-7|pages=50–}}</ref>

===In infants===
{{main|Primitive reflexes}}
[[Infant]]s will usually show an extensor response. In one study of 256 healthy infants, the response to testing was extensor in 73.8%, flexor in 8.9%, and equivocal in 17.3%<ref>{{cite journal|last1=Gupta|first1=A|last2=Gupta|first2=Piyush|title=Neonatal plantar response revisited |journal=Journal of Paediatrics and Child Health|date=July 2003|volume=39|issue=5|pages=349–351|doi=10.1046/j.1440-1754.2003.00172.x|pmid=12887664|s2cid=19382928}}</ref> This extensor response occurs because the [[corticospinal tract|corticospinal pathways]] that run from the [[Human brain|brain]] down the [[spinal cord]] are not fully [[myelin]]ated at this age, so the reflex is not inhibited by the [[cerebral cortex]]. The extensor response usually disappears – giving way to the flexor response – by 12 months of age.<ref>{{cite web|title=Neonatal reflexes|url=http://www.healthofchildren.com/N-O/Neonatal-Reflexes.html|access-date=24 May 2017}}</ref> Its persistence beyond age 2–3 indicates a problem in the brain or spinal cord.<ref>{{cite web|title=Medline plus: Babinski reflex|url=https://medlineplus.gov/ency/article/003294.htm|access-date=24 May 2017}}</ref><ref>{{cite journal|last1=Neelon|first1=Francis A|last2=Harvey|first2=Elisabeth|title=The Babinski Sign|journal=N Engl J Med|volume=340|issue=3|pages=196|date=January 21, 1999|doi=10.1056/NEJM199901213400305|pmid=9895399}}</ref>

===Pathways===
* Afferent: [[Nociception]] detected in the S1 [[Dermatome (anatomy)|dermatome]] and travels up the [[tibial nerve]] to the [[sciatic nerve]] to roots of L5,S1 and synapse in the [[Anterior horn of lateral ventricle|anterior horn]] to elicit the motor response.
* Efferent: Motor response back through the L5,S1 roots to the sciatic nerve to its bifurcation.  Toe flexors are innervated by the tibial nerve. Toe extensors ([[Extensor hallucis longus muscle|extensor hallucis longus]], [[Extensor digitorum longus muscle|extensor digitorum longus)]] are innervated by the [[deep peroneal nerve]]. Loss of normal adult descending pyramidal control of the reflex arc to suppress extensor withdrawal results in the upgoing toes in the plantar reflex known as Babinski's sign.<ref>{{cite journal|last1=Futagi|first1=Y|last2=Suzuki|first2=Y|title=Neural mechanism and clinical significance of the plantar grasp reflex in infants.|journal=Pediatric Neurology|date=August 2010|volume=43|issue=2|pages=81–6|doi=10.1016/j.pediatrneurol.2010.04.002|pmid=20610116}}</ref>