Axillary nerve
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2008-06-20T00:15:35Z
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robot Adding: [[nl:Nervus axillaris]]
{{Infobox Nerve |
Name = Axillary nerve |
Latin = nervus axillaris|
GraySubject = 210 |
GrayPage = 934 |
Image = Brachial_plexus.JPG |
Caption = Brachial plexus. (Axillary nerve is visible in gray near center.) |
Image2 = Gray818.png |
Caption2 = The [[suprascapular nerve|suprascapular]], [[axillary nerve|axillary]], and [[radial nerve]]s. (Axillary labeled at upper right.) |
Innervates = [[deltoid]], [[teres minor]], [[axilla]] |
BranchFrom = [[posterior cord]] (C5, C6) |
BranchTo = |
MeshName = |
MeshNumber = |
DorlandsPre = n_05 |
DorlandsSuf = 12565259 |
}}
The '''axillary nerve''' is a [[nerve]] of the human body, that comes off the [[posterior cord]] of the [[brachial plexus]] at the level of the [[axilla]] (armpit) and carries nerve fibers from C5 and C6. The axillary nerve travels through the [[quadrangular space]] with the [[posterior circumflex humeral artery]] and vein.
==Muscular and sensory innervation==
It supplies two [[muscle]]s, [[deltoid]] (a muscle of the shoulder), and [[teres minor]] (one of the [[rotator cuff]] muscles).
The axillary nerve also carries sensory information from the [[shoulder joint]], as well as the skin covering the inferior region of the deltoid muscle - the "regimental badge" area (which is innervated by the [[Superior lateral cutaneous nerve of arm|Superior Lateral Cutaneous Nerve]] branch of the Axillary nerve).
When the axillary nerve splits off from the posterior cord, the continuation of the cord is the [[radial nerve]].
==Branches==
It lies at first behind the [[axillary artery]], and in front of the [[Subscapularis]], and passes downward to the lower border of that muscle.
It then winds backward, in company with the posterior humeral circumflex artery, through a quadrilateral space bounded above by the Teres Minor, below by the [[Teres major]], medially by the long head of the [[Triceps brachii]], and laterally by the [[surgical neck]] of the humerus, and divides into an anterior and a posterior branch.
* The ''anterior branch'' (upper branch) winds around the [[surgical neck of the humerus]], beneath the Deltoideus, with the posterior humeral circumflex vessels, as far as the anterior border of that muscle, supplying it, and giving off a few small cutaneous branches, which pierce the muscle and ramify in the skin covering its lower part.
* The ''posterior branch'' (lower branch) supplies the Teres minor and the posterior part of the Deltoideus; upon the branch to the Teres minor an oval enlargement (pseudoganglion) usually exists. The posterior branch then pierces the deep fascia and is continued as the lateral brachial cutaneous nerve, which sweeps around the posterior border of the Deltoideus and supplies the skin over the lower two-thirds of the posterior part of this muscle, as well as that covering the long head of the Triceps brachii.
The trunk of the axillary nerve gives off an articular filament which enters the [[shoulder-joint]] below the Subscapularis.
==Injury==
The axillary nerve may be injured in anterior dislocations of the shoulder joint, compression of the axilla with a crutch or fracture of the surgical neck of the humerus. Injury to the nerve results in: -
1. Paralysis of the teres minor and deltoid muscles. Abduction of the shoulder is impaired.
2. Loss of sensation over a small part of the lateral upper arm
==Additional images==
<gallery>
Image:Brachial plexus.svg|Brachial plexus
Image:Gray810.png|Suprascapular and axillary nerves of right side, seen from behind.
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:Gray1236.png|Back of right upper extremity, showing surface markings for bones and nerves.
</gallery>
==External links==
* {{DukeOrtho|axillary_nerve}}
* {{eMedicineDictionary|Axillary+nerve}}
{{Gray's}}
{{Brachial plexus}}
[[Category:Peripheral nervous system]]
[[Category:Upper limb anatomy]]
[[de:Nervus axillaris]]
[[es:Nervio circunflejo]]
[[fr:Nerf axillaire]]
[[nl:Nervus axillaris]]
[[pl:Nerw pachowy]]
[[sv:Nervus axillaris]]