Editing Carpal tunnel syndrome (section)

== Signs ==
Severe CTS is associated with measurable loss of sensibility.  Diminished threshold sensibility (the ability to distinguish different amounts of pressure) can be measured using Semmes-Weinstein monofilament testing.<ref>{{cite journal | vauthors = Szabo RM, Gelberman RH, Dimick MP | title = Sensibility testing in patients with carpal tunnel syndrome | journal = The Journal of Bone and Joint Surgery. American Volume | volume = 66 | issue = 1 | pages = 60–64 | date = January 1984 | pmid = 6690444 | doi = 10.2106/00004623-198466010-00009 }}</ref> Diminished discriminant sensibility can be measured by testing two-point discrimination: the number of millimeters two points of contact need to be separated before you can distinguish them.<ref>{{cite journal | vauthors = Elfar JC, Yaseen Z, Stern PJ, Kiefhaber TR | title = Individual finger sensibility in carpal tunnel syndrome | journal = The Journal of Hand Surgery | volume = 35 | issue = 11 | pages = 1807–1812 | date = November 2010 | pmid = 21050964 | pmc = 4410266 | doi = 10.1016/j.jhsa.2010.08.013 }}</ref>

A person with idiopathic carpal tunnel syndrome will not have any sensory loss over the [[thenar eminence]] (bulge of muscles in the palm of hand and at the base of the thumb). This is because the palmar branch of the median nerve, which innervates that area of the palm, separates from the median nerve and passes over the carpal tunnel.<ref>{{Cite book | vauthors = Netter F |title=Atlas of Human Anatomy |publisher=Saunders Elsevier |year=2011 |isbn=978-0-8089-2423-4 |edition=5th |location=Philadelphia, PA |page=447}}</ref>

Severe CTS is also associated with weakness and [[atrophy]] of the muscles at the base of the thumb.  The ability to palmarly abduct the thumb may be lost. CTS can be detected on examination using one of several maneuvers to provoke paresthesia (a sensation of tingling or "pins and needles" in the median nerve distribution).  These so-called provocative signs include:
* [[Phalen's maneuver]]. Performed by fully flexing the wrist, then holding this position and awaiting symptoms.<ref name="Harrison">{{Cite book |title=Harrison's Principles of Internal Medicine |vauthors=Cush JJ, Lipsky PE |publisher=McGraw-Hill Professional |year=2004 |isbn=978-0-07-140235-4 |edition=16th |page=2035 |chapter=Approach to articular and musculoskeletal disorders}}</ref> A positive test is one that results in paresthesia in the median nerve distribution within sixty seconds.
* [[Tinel's sign]] is performed by lightly tapping the median nerve just proximal to [[Flexor retinaculum of the hand|flexor retinaculum]] to elicit paresthesia.<ref name="Padua2016" />
* [[Durkan's test]], ''carpal compression test'', or applying firm pressure to the palm over the nerve for up to 30 seconds to elicit paresthesia.<ref name="Gonzalez_1997">{{cite journal | vauthors = González del Pino J, Delgado-Martínez AD, González González I, Lovic A | title = Value of the carpal compression test in the diagnosis of carpal tunnel syndrome | journal = Journal of Hand Surgery | volume = 22 | issue = 1 | pages = 38–41 | date = February 1997 | pmid = 9061521 | doi = 10.1016/S0266-7681(97)80012-5 | s2cid = 25924364 }}</ref><ref name="Durkan_1991">{{cite journal | vauthors = Durkan JA | title = A new diagnostic test for carpal tunnel syndrome | journal = The Journal of Bone and Joint Surgery. American Volume | volume = 73 | issue = 4 | pages = 535–538 | date = April 1991 | pmid = 1796937 | doi = 10.2106/00004623-199173040-00009 | s2cid = 11545887 }}</ref>
* [[Hand elevation test]] The hand elevation test is performed by lifting both hands above the head. Paresthesia in the median nerve distribution within 2 minutes is considered positive.

Diagnostic performance characteristics such as sensitivity and specificity are reported, but difficult to interpret because of the lack of a consensus reference standard for CTS.