Variation of Musculocutaneous Nervi Branching to Median Nerve and not Piercing Corocobrachialis Muscle; Case Report

Öz

The fifth and sixth (and sometimes the fourth) cervical spinal nerves merge to form the superior trunk, and the superior trunk and the anterior part of the median nerve merge to form the fasciculus lateralis. Fasciculus lateralis is divided into two branches as lateral cord and musculocutaneous nerve. The mus-culocutaneous nerve pierces the corocobrachialis muscle muscle and then travels between the brachia-lis muscle and the biceps brachii musculus. Variations in anatomical structures are common. However, nerve variations occur more rarely in these structures. These variations are anatomically and clinically important. This case report was detected during routine dissection of a male cadaver in the Depart-ment of Anatomy, Karabuk University Faculty of Medicine. For dissection, the fossa axillaris, arm and forearm of both upper extremities were dissected. During dissection, it was found that the musculocu-taneous nerve in the left upper extremity continued without piercing the corocobrachialis muscle and gave a connecting branch to the median nerve. There are limited case studies on this nerve variation and studies show that this variational condition is important for surgical operations in this region. The-refore, this study is important for both surgical and clinical sciences.

Anahtar Kelimeler

• Musculocutaneous nerve
• Corocobrachialis muscle
• Median nerve
• Variation

Etik Beyan

The authors confirm that they have complied with ethical guidelines for cadaveric studies. Since it is a cadaveric study, permission by the ethics committee is not required.

Teşekkür

The authors would like to express their endless gratitude to the body donors and their families who have made great contributions to the science of anatomy.

Nervus Medianus’a Dal Veren ve Musculus Corocobrachialis’i Delmeyen Nervus Musculocutaneus Varyasyonu; Olgu Sunumu

Öz

Beşinci ve altıncı (bazen de dördüncü) servikal spinal sinirler birleşerek truncus superior’u, truncus superior ile nervus medianus’un ön bölümü de birleşerek fasciculus lateralis’i meydana getirir. Fascicu-lus lateralis’te radix lateralis ve nervus musculocutaneus olmak üzere iki dala ayrılır. Nervus musculocu-taneus’da musculus corocobrachialis kasını deler ve sonrasında musculus brachialis ile musculus biceps brachii arasında seyreder. Anatomik yapılarda varyasyonlar gözüken bir durumdur. Fakat bu yapılar içerisinde sinir varyasyonları daha nadir olarak ortaya çıkmaktadır. Bu varyasyonlarda anatomik ve klinik açıdan önemlidir. Bu olgu sunumu Karabük üniversitesi Tıp Fakültesi Anatomi Anabilim dalı’nda yer alan erkek kadavranın rutin diseksiyonu sırasında tespit edildi. Diseksiyon için her iki üst extremitenin de fossa axillaris’i, kol ve ön kol bölgesi diseke edildi. Diseksiyon sırasında sol üst extremitede yer alan nervus musculocutaneus’un musculus corocobrachialis’i delmeden devam ettiği ve nervus medianus’a birleştirici bir dal verdiği bulundu. Bu sinir varyasyonu ile ilgili sınırlı vaka çalışması bulunmakta olup çalışmalar bu varyasyonel durumun bu bölgedeki cerrahi operasyonlar için önemli olduğunu göstermek-tedir. Bundan dolayı bu çalışma hem cerrahi bilimler için hem de klinik bilimler için önem arz etmek-tedir.

Anahtar Kelimeler

• Nervus musculocutaneus
• Musculus corocobrachialis
• Nervus medianus
• Varyasyon

Kaynakça

1. 1. Larrotta DRB, Porras PLF, Acuña LEB, Ballesteros D, Forero P, Ballesteros L. Anatomic variations in relation to the origin of the musculocutaneous nerve: absence and non-perforation of the coracobrachialis muscle. Anatomical study and clinical significance. Int J Morphol. 2018;36(2):425-9.
2. 2. Ertürk H, Şanlı OC, Öztürk K, Kastamoni Y. Nervus Musculocu-taneus’ un Oluşum Varyasyonları. Uludağ Üniversitesi Tıp Fakültesi Dergisi. 2023;49(3):361-5.
3. 3. Apaydin N, Şen T, Bozkurt M, Elhan A. Nervus musculocutane-us' un Dallanma Paterni ve Klinik Önemi. Turkiye Klinikleri Journal of Medical Sciences. 2009;29(2):464-8.
4. 4. Ghosh B, Dilkash MNA, Prasad S, Sinha SK. Anatomical varia-tion of median nerve: cadaveric study in brachial plexus. Anatomy & cell biology. 2022;55(2):130-4.
5. 5. Beheiry EE. Anatomical variations of the median nerve distri-bution and communication in the arm. Folia morphologica. 2004;63(3):313-8.
6. 6. Encarnacion M, Nurmukhametov R, Barrientos RE, Melchenko D, Goncharov E, Bernard E, et al. Anatomical variations of the median nerve: A cadaveric study. Neurology International. 2022;14(3):664-72.
7. 7. Uzun A, Seelig LL. A variation in the formation of the median nerve: communicating branch between the musculocutane-ous and median nerves in man. Folia Morphologica. 2001;60(2):99-101.
8. 8. Bala A, Sinha P, Tamang BK, Sarda RK. Anatomical variation: Median nerve formation–A case vignette. Journal of Clinical and Diagnostic Research: JCDR. 2014;8(6):AD03.

9. 9. Soubeyrand M, Melhem R, Protais M, Artuso M, Crézé M. Anatomy of the median nerve and its clinical applications. Hand Surgery and Rehabilitation. 2020;39(1):2-18.
10. 10. Radunovic M, Vukasanovic-Bozaric A, Radojevic N, Vukadinovic T. A new anatomical variation of the musculocutaneous and the median nerve anastomosis. Folia morphologica. 2013;72(2):176-9.
11. 11. Pacholczak R, Klimek-Piotrowska W, Walocha JA. Absence of the musculocutaneous nerve associated with a supernumer-ary head of biceps brachii: a case report. Surgical and radio-logic anatomy. 2011;33:551-4.
12. 12. Kocabiyik N, Yalcin B, Yazar F, Ozan H. An accessory branch of musculocutaneous nerve joining median nerve. Neuroanato-my. 2005;4:13-5.
13. 13. Venieratos D, Anagnostopoulou S. Classification of communi-cations between the musculocutaneous and median nerves. Clinical Anatomy: The Official Journal of the American Associa-tion of Clinical Anatomists and the British Association of Clini-cal Anatomists. 1998;11(5):327-31.
14. 14. Basar R, Aldur M, Celik H, Yüksel M, Tascioglu A. A connecting branch between the musculocutaneous nerve and the medi-an nerve. Morphologie: bulletin de l'Association des anato-mistes. 2000;84(266):25-7.
15. 15. Sarikcioglu L, Coskun N, Ozkan O. A case with multiple anoma-lies in the upper limb. Surgical and Radiologic Anatomy. 2001;23:65-8.
16. 16. Choi D, Rodríguez‐Niedenführ M, Vázquez T, Parkin I, Sañudo JR. Patterns of connections between the musculocutaneous and median nerves in the axilla and arm. Clinical Anatomy. 2002;15(1):11-7.