Accessory brachialis muscle
Citation, DOI, disclosures and article data
Citation:
Feger J, Bell D, Accessory brachialis muscle. Reference article, Radiopaedia.org (Accessed on 18 Mar 2025) https://doi.org/10.53347/rID-91675
rID:
91675
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Disclosures:
At the time the article was created Joachim Feger had no recorded disclosures.
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Last revised:
Disclosures:
At the time the article was last revised Joachim Feger had no recorded disclosures.
View Joachim Feger's current disclosures
Revisions:
4 times, by
2 contributors -
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Systems:
Tags:
Synonyms:
- Brachialis accessorius muscle
An accessory brachialis muscle, also known as brachialis accessorius muscle, is a very rare accessory muscle of the elbow and an anatomical variant.
On this page:
Summary
- origin: anterior surface of the lower humeral diaphysis
- course: variably medial or lateral to the brachialis muscle
- insertion: variable, including pronator teres or common flexor tendon and proximal radial shaft
- innervation: musculocutaneous nerve or median nerve
Gross anatomy
Descriptions of origin and course of accessory brachialis muscles have been quite variable. They seem to originate from the anterior lower diaphysis and either medial or lateral intermuscular septum with some reports describing it coursing medially 1-4 and others lateral to the brachialis muscle 5,6.
It might form a fibromuscular tunnel with the intermuscular septum containing the median nerve and the brachial artery 2 continuing into the cubital tunnel together with those neurovascular structures 2-4.
Radiographic features
The accessory brachialis muscle might be visualised on imaging studies such as MRI or ultrasound coursing adjacent to the brachialis muscle.
History and etymology
A slip of the brachialis anticus muscle coursing over the brachial vessels and the median nerve had been already described by the British surgeon and anatomist John Wood (1825-1891) in 1867 7,9.
Clinical importance
An accessory brachialis muscle might be mistaken for a soft tissue tumour, its knowledge is also helpful in patients undergoing elbow surgery 2.
Related pathology
- accessory brachialis muscle might be involved in nerve compression syndromes such as the median nerve or brachial artery claudication 2
References
- 1. Loukas M, Louis R, South G, Alsheik E, Christopherson C. A Case of an Accessory Brachialis Muscle. Clin Anat. 2006;19(6):550-3. doi:10.1002/ca.20285 - Pubmed
- 2. Akhtar M, Fatima N, Kumar S, Kumar B, Kumar V. An Accessory Brachialis Muscle Associated with Abnormal Arrangement of Structures in the Cubital Fossa. Int J Res Med Sci. 2015;3(12):3907-10. doi:10.18203/2320-6012.ijrms20151469
- 3. Vadgaonkar R, Rai R, Ranade A, Nayak S, Pai M, Lakshmi R. A Case Report on Accessory Brachialis Muscle. Rom J Morphol Embryol. 2008;49(4):581-3. - Pubmed
- 4. Paraskevas G, Natsis K, Ioannidis O, Papaziogas B, Kitsoulis P, Spanidou S. Accessory Muscles in the Lower Part of the Anterior Compartment of the Arm That May Entrap Neurovascular Elements. Clin Anat. 2008;21(3):246-51. doi:10.1002/ca.20608 - Pubmed
- 5. Nelluri V, Swamy R, Nayak S, Kumar N, Patil J. Bulky Accessory Brachialis Muscle with Abnormal Aponeurosis: A Case Report. Proceedings of Singapore Healthcare. 2016;25(4):249-251. doi:10.1177/2010105816641698
- 6. Pai M, Nayak S, Vadgaonkar R et al. Accessory Brachialis Muscle: A Case Report. Morphologie. 2008;92(296):47-9. doi:10.1016/j.morpho.2008.04.003 - Pubmed
- 7. Wood J. IV. Variations in Human Myology Observed During the Winter Session of 1866-67 at King's College, London. Proc R Soc Lond. 1867;15:518-46. doi:10.1098/rspl.1866.0119
- 8. Sookur P, Naraghi A, Bleakney R, Jalan R, Chan O, White L. Accessory Muscles: Anatomy, Symptoms, and Radiologic Evaluation. Radiographics. 2008;28(2):481-99. doi:10.1148/rg.282075064 - Pubmed
- 9. British Medical Journal Publishing Group. John Wood, F.R.S., F.R.C.S. BMJ. 1892;1(1619):96-7. doi:10.1136/bmj.1.1619.96
Incoming Links
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