Anconeus muscle

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Anconeus muscle
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Back of right upper extremity. (Anconeus labeled at bottom center.)
Musculusanconeus2.png
Posterior surface of the forearm. Superficial muscles. (Anconeus visible at center right.)
Latin musculus anconeus
Gray's subject #125 454
Origin lateral epicondyle of the humerus proximally
Insertion    lateral surface of the olecranon process and the superior part of the posterior ulna distally
Artery deep brachial artery, recurrent interosseous artery
Nerve radial nerve (C7, C8, and T1)
Actions It is partly blended in with the triceps, which it assists in extension of the forearm. It also stabilizes the elbow during pronation and supination and pulls slack out of the elbow joint capsule during extension to prevent impingement.

The anconeus muscle (or anconaus/anconæus) is a small muscle on the posterior aspect of the elbow joint.

Some consider anconeus to be a continuation of the triceps brachii muscle.[1][2][3] Some sources consider it to be part of the posterior compartment of the arm,[4] while others consider it part of the posterior compartment of the forearm.[5]

The Anconeus muscle can easily be palpated just lateral to the olecranon process of the ulna.

Contents

Origin and insertion

Anconeus originates on the posterior surface of the lateral epicondyle of the humerus and is inserted on the ulna lateral to the olecranon from where it extends down on the dorsal side of the bone. [6]

Function

Arteries and nerves of the back of the arm

Its function is trivial in humans. It assists in extension of the elbow, where the triceps brachii is the principal agonist, and supports the elbow in full extension.[6] It also prevents the elbow joint capsule being pinched in the olecranon fossa during extension of the elbow. Anconeus also abducts the ulna and stabilizes the elbow joint.

Innervation

Anconeus is innervated by the radial nerve (cervical roots 7 and 8)[6] from the posterior cord of the brachial plexus. The somatomotor portion of radial nerve innervating anconeus bifurcates from the main branch in the radial groove of the humerus. This innervation pattern follows the rules of innervation of the musculature of the posterior forearm (extensor) compartment by the radial nerve.

Blood supply

Anconeus is supplied by the middle collateral artery from the profunda brachii artery.[6]

Additional images

Posterior view of left humerus  
Posterior aspect of bones of left forearm  
Deep muscles of posterior surface of the forearm  
Forearm posterior view  

References

  1. ^ Williams, P. et al., 1995, Gray's Anatomy, 38th ed., Churchill Livingstone
  2. ^ Jones, W. et al.(eds) , 1953, Buchanan's Manual of Anatomy, 8th ed., Balliére, Tindall and Cox., pp. 496
  3. ^ Grant, J. & Basmajian J., 1965, Grant's Method of Anatomy, 7th ed., The Williams & Wilkins Company, Baltimore, pp. 163-164
  4. ^ "Dissector Answers — Axilla & Arm". http://anatomy.med.umich.edu/musculoskeletal_system/axilla_ans.html. Retrieved 2008-01-17. 
  5. ^ "The Radius and Ulna". Archived from the original on 2008-06-11. http://web.archive.org/web/20080611032919/http://www.med.mun.ca/anatomyts/msk/forearm.htm. Retrieved 2008-01-17. 
  6. ^ a b c d "Anconeus". The Hosford Muscle Tables. http://www.ptcentral.com/muscles/musclearms.html#anconeus. Retrieved February 2012. 



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