Ulnar nerve
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2008-07-11T07:35:46Z
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{{Infobox Nerve |
Name = Ulnar nerve |
Latin = nervus ulnaris |
GraySubject = 210 |
GrayPage = 943 |
Image = Brachial_plexus.JPG |
Caption = Click image to enlarge - ulnar nerve is visible in lower left |
Image2 = Nerves_of_the_left_upper_extremity.gif |
Caption2 = Nerves of the left upper extremity. (Ulnar labeled at center left.) |
Innervates = [[flexor carpi ulnaris]]<BR>[[flexor digitorum profundis]]<BR>[[lumbrical muscle]]s<BR>[[opponens digiti minimi]]<BR>[[Flexor digiti minimi brevis (hand)|flexor digiti minimi]]<BR>[[Abductor minimi digiti muscle (hand)|abductor digiti minimi]]<BR>[[interossei]]<BR>[[adductor pollicis]] |
BranchFrom = [[Medial cord]] |
BranchTo = |
MeshName = Ulnar+nerve |
MeshNumber = A08.800.800.720.050.850 |
DorlandsPre = n_05 |
DorlandsSuf = 12566994 |
}}
In [[human anatomy]], the '''ulnar nerve''' is a nerve which runs near the [[ulna]] bone. Aggravation of this nerve is commonly referred to as hitting one's "'''funny bone'''." The ulnar nerve is the largest unprotected nerve in the human body (meaning, unprotected by muscle or bone), and the only unprotected nerve that does not serve a sensory function (those nerves specifically meant to perceive changes in the environment, such as nerves in the skin).
==Course==
=== Arm ===
The ulnar nerve comes from the medial cord of the [[brachial plexus]], and runs inferior on the posterior and medial (posteromedial) aspects of the [[humerus]] down the arm, going behind the [[medial epicondyle]], through the [[cubital tunnel]], at the [[Elbow-joint| elbow]] (where it is exposed for a few centimeters, just above the joint). Because of the mild pain and tingling throughout the forearm associated with an inadvertent impact of the nerve at this point, it is usually called the '''funny bone'''. (It may also have to do with its location relative to the humerus, as the name "humerus" is a [[homophone]] to the word "[[humor]]ous").
===Forearm===
It enters the anterior (flexor/front) compartment of the forearm through the two heads of flexor carpi ulnaris and runs alongside the [[ulna]]. There it supplies one and a half muscles (flexor carpi ulnaris & medial half of flexor digiti profundus). It soon joins with the [[ulnar artery]], and the two travel inferiorly together, deep to the [[flexor carpi ulnaris]] muscle.
Here it gives off the following branches: <ref name="isbn0-443-07168-3">{{cite book |author=Ellis, Harold; Susan Standring; Gray, Henry David |title=Gray's anatomy: the anatomical basis of clinical practice |publisher=Elsevier Churchill Livingstone |location=St. Louis, Mo |year=2005 |pages=700 |isbn=0-443-07168-3 |oclc= |doi=}}</ref>
* [[muscular branches of ulnar nerve]]
* [[palmar branch of ulnar nerve]]
* [[dorsal branch of ulnar nerve]]
===Hand===
After it travels down the ulna, the ulnar nerve enters the palm of the hand. Unlike the [[median nerve]] which travels below the [[flexor retinaculum of the hand]] and through the [[carpal tunnel]], the ulnar nerve and artery pass superficial to the [[flexor retinaculum of the hand|flexor retinaculum]] via the [[ulnar canal]].
Here it gives off the following branches: <ref name="isbn0-443-07168-3">{{cite book |author=Ellis, Harold; Susan Standring; Gray, Henry David |title=Gray's anatomy: the anatomical basis of clinical practice |publisher=Elsevier Churchill Livingstone |location=St. Louis, Mo |year=2005 |pages=726 |isbn=0-443-07168-3 |oclc= |doi=}}</ref>
* [[Superficial branch of ulnar nerve]]
* [[Deep branch of ulnar nerve]]
==Branches and innervation==
===Muscular===
The ulnar nerve and its branches innervate the following muscles in the forearm and hand:
An Articular branch that passes to the elbow joint while the ulnar nerve is passing between the olecranon and medial epicondyle of the humerus.
*In the [[forearm]], via the [[muscular branches of ulnar nerve]]:
**[[Flexor carpi ulnaris]]
**[[Flexor digitorum profundus]] (medial half)
*In the [[hand]], via the [[deep branch of ulnar nerve]]:
**[[hypothenar]] muscles
***[[Opponens digiti minimi]]
***[[Abductor minimi digiti muscle (hand)|Abductor digiti minimi]]
***[[Flexor digiti minimi brevis (hand)|Flexor digiti minimi brevis]]
**[[Adductor pollicis]]
**The third and fourth [[Lumbricals of the hand|lumbrical muscles]]
**[[Dorsal interossei of the hand|Dorsal interossei]]
**[[Palmar interossei]]
*In the hand, via the [[superficial branch of ulnar nerve]]:
**[[Palmaris brevis]]
===Cutaneous===
The ulnar nerve also provides [[sensory innervation]] to the part of the hand corresponding to the fourth and fifth digits:
* [[Palmar branch of ulnar nerve]] - anterior
* [[Dorsal branch of ulnar nerve]] - posterior
==Ulnar nerve entrapment==
{{main|Ulnar nerve entrapment}}
The Ulnar nerve can be trapped or pinched in various ways as it proceeds down the arm from the Brachial plexus to the ring and middle fingers. One common cause is [[cubital tunnel]] syndrome, where the tunnel runs the inner outside side of the elbow. Pinching of the nerve often causes tingling symptoms in the little and ring fingers. In some cases moderate to severe pain is experienced from pinching this nerve. Often such [[Paresthesia|pins and needles]] sensations can be caused by sleeping wrongly on your arm, but sometimes the problems last for days. In severe cases, surgery is performed to move the nerve.
==See also==
* [[Radial nerve]]
* [[Axillary nerve]]
* [[Median nerve]]
* [[Musculocutaneous nerve]]
==Additional images==
<gallery>
Image:Brachial plexus.svg|Brachial plexus
Image:Gray413_color.png|Cross-section through the middle of upper arm.
Image:Gray417_color.PNG|Cross-section through the middle of the forearm.
Image:Gray421.png|Transverse section across distal ends of radius and ulna.
Image:Gray422.png|Transverse section across the wrist and digits.
Image:Gray425.png|The palmar aponeurosis.
Image:Gray523.png|The axillary artery and its branches.
Image:Gray525.png|The brachial artery.
Image:Gray528.png|Ulnar and radial arteries. Deep view.
Image:Gray809.png|The right brachial plexus (infraclavicular portion) in the axillary fossa; viewed from below and in front.
Image:Gray811and813.PNG|Cutaneous nerves of right upper extremity.
Image:Gray812and814.PNG|Diagram of segmental distribution of the cutaneous nerves of the right upper extremity.
Image:Gray815.png|Superficial palmar nerves.
Image:Gray817.png|Deep palmar nerves.
Image:Gray1235.png|Front of right upper extremity, showing surface markings for bones, arteries, and nerves.
Image:Gray1236.png|Back of right upper extremity, showing surface markings for bones and nerves.
</gallery>
==References==
{{reflist}}
==External links==
* {{eMedicineDictionary|Ulnar+nerve}}
* [http://www.cubital-tunnel.com Cubital Tunnel Support Forums]
* {{SUNYAnatomyFigs|05|03|15}} - "The major subdivisions and terminal nerves of the [[brachial plexus]]."
* {{SUNYAnatomyFigs|07|04|04}} - "Anterior view of the nerves, vessels, and superficial tendons that cross the left [[wrist]]."
* {{SUNYAnatomyFigs|08|03|07}} - "Transverse section through the [[carpal tunnel]] and distal row of the [[carpal]] bones."
* {{DukeOrtho|ulnar_nerve}}
* {{MUNAnatomy|nerve/ulnerv}}
* {{KansasHandKinesiology|nerves/ulnar.htm}}
* {{UMichAtlas|hand_plexus}} - "Axilla, dissection, anterior view"
* [http://www.neuro.wustl.edu/neuromuscular/nanatomy/ulnar.htm Overview at neuro.wustl.edu]
{{Brachial plexus}}
[[Category:Peripheral nervous system]]
[[Category:Upper limb anatomy]]
[[de:Nervus ulnaris]]
[[fr:Nerf ulnaire]]
[[he:עצב הגומד]]
[[nl:Telefoonbotje]]
[[pt:nervo ulnar]]
[[pl:Nerw_%C5%82okciowy]]
[[sv:Nervus ulnaris]]