Wrist drop
357765
222311209
2008-06-28T17:31:31Z
Theskyrider99
7389310
/* Causes */
{{Infobox_Disease |
Name = {{PAGENAME}} |
Image = Gray818.png |
Caption = The [[suprascapular nerve|suprascapular]], [[axillary nerve|axillary]], and radial nerves. |
Width = 150 |
DiseasesDB = |
ICD10 = {{ICD10|M|21|3|m|20}} |
ICD9 = {{ICD9|736.05}} |
ICDO = |
OMIM = |
MedlinePlus = |
eMedicineSubj = |
eMedicineTopic = |
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}}
'''Wrist drop''', also known as '''[[radial nerve]] palsy''', is a condition where a person can not extend their [[wrist]] and it hangs [[flaccidly]]. To demonstrate wrist drop, hold your arm out in front of you with your forearm parallel to the floor. With the back of your hand facing the ceiling (i.e. [[pronated]]), let your hand hang limply so that your fingers point downward. A person with wrist drop would be unable to move from this position to one in which the fingers are pointing up towards the ceiling.
==Anatomy of the forearm==
In anatomical parlance, the [[forearm]] is the part of the body which extends from the elbow to the wrist and is not to be confused with the arm which extends from the shoulder to the elbow. The extensor muscles in the forearm are [[extensor carpi ulnaris]], [[extensor digiti minimi]], [[extensor digitorum]], [[extensor indicis]], [[extensor pollicis longus]], [[extensor pollicis brevis]], [[extensor carpi radialis brevis]], [[extensor carpi radialis longus]]. These extensor muscles are supplied by the [[radial nerve]]. Other muscles in the forearm also innervated by the radial nerve are [[brachioradialis]], [[supinator]] and [[abductor pollicis longus]]. Note that all these muscles are situated in the posterior half of the forearm (posterior when in the [[anatomical position]]).
==Causes==
Wrist extension is achieved by [[muscle]]s in the [[forearm]] contracting, pulling on [[tendon]]s that attach distal to (beyond) the wrist. If the tendons, the muscles, or the [[nerve]]s supplying these muscles, are not working as they should be, wrist drop may occur. The following situations may result in wrist drop:
Stab wounds to the chest at or below the clavicle may result in wrist drop. The radial nerve is the terminal branch of the posterior cord of the [[brachial plexus]]. A stab wound may damage the posterior cord and result in neurological deficits including an inability to abduct the shoulder beyond 15 degrees, an inability to extend the forearm, reduced ability to supinate the hand, reduced ability to abduct the thumb and sensory loss to the posterior surface of the arm and hand.
The radial nerve can be damaged if the humerus (the bone of the arm) is broken, because it runs through the radial groove on the lateral border of this bone.
Wrist drop is also associated with [[lead poisoning]] because of the effect of [[lead]] on the radial nerve.<ref name="pmid16808730">{{cite journal |author=Dedeken P, Louw V, Vandooren AK, Geert V, Goossens W, Dubois B |title=Plumbism or lead intoxication mimicking an abdominal tumor |journal=Journal of general internal medicine : official journal of the Society for Research and Education in Primary Care Internal Medicine |volume=21 |issue=6 |pages=C1–3 |year=2006 |pmid=16808730 |doi=10.1111/j.1525-1497.2006.00328.x}}</ref>
Persistent injury to the nerve is also a common cause through either repetitive motion or by applying pressure externally along the route of the radial nerve as in the prolonged use of crutches or extended leaning on the elbows.
==Diagnosis==
The workup for wrist drop frequently includes nerve conduction velocity studies to isolate and confirm the radial nerve as the source of the problem. Plain films can help identify bone spurs and fractures that may have injured the nerve. Sometimes MRI imaging is required to differentiate subtle causes.
==Treatment==
Initial management includes [[splinting]] of the wrist for support along with [[occupational therapy|occupational]] or [[physical therapy]]. In some cases [[surgical]] removal of bone spurs or other anatomical defects that may be impinging on the nerve might be warranted.
==See also==
* [[Radial neuropathy]]
==References==
<references/>
==External links==
* {{NormanAnatomy|clinicalconsiderations}}
* {{GPnotebook|617611280}}
{{Diseases of the musculoskeletal system and connective tissue}}
[[Category:Diseases]]
[[es:Parálisis del nervio radial]]