Anatomy Atlases(tm) : A digital library of anatomy information

Home | Search | About Us | FAQ | Reviews | Contact Us

Anatomy Atlases: Illustrated Encyclopedia of Human Anatomic Variation: Opus III: Nervous System: Plexuses: Musculocutaneous Nerve

Illustrated Encyclopedia of Human Anatomic Variation: Opus III: Nervous System: Plexuses

Musculocutaneous Nerve

Ronald A. Bergman, PhD
Adel K. Afifi, MD, MS
Ryosuke Miyauchi, MD

Peer Review Status: Internally Peer Reviewed

This nerve arises from the lateral cord (90.5% of 75 arms), from the lateral and posterior (4%), from the median nerve (2%), as two separate bundles from the medial and lateral cords (1.4%), or from the posterior cord (1.4%).

A number of variations in the course and distribution of the musculocutaneous nerve have been reported. Instead of piercing the coracobrachialis muscle, the nerve may adhere to the median nerve for some distance down the arm and then, either as a single trunk or as several branches, pass between the biceps and brachialis muscles to supply all three muscles (about 22% of arms).

Sometimes only a part of the nerve follows this course; this part then rejoins the main trunk after it transits through and supplies coracobrachialis.

In some cases, instead of the whole trunk of the nerve piercing coracobrachialis, only its muscular branch or only its cutaneous branch pierces the muscle.

The musculocutaneous nerve may be accompanied by fibers from the median nerve as its transits coracobrachialis; a communicating branch passes from the musculocutaneous to the median nerve. Instead of penetrating coracobrachialis, the nerve may pass behind it or between it and the short head of the biceps muscle. Occasionally, the nerve perforates, not only coracobrachialis, but also the brachialis or the short head of the biceps muscles.

Very rarely the lateral cord may pierce coracobrachialis and then divide into the musculocutaneous and lateral branch of the median nerve.

Branches to the following structures have been reported: brachioradialis, pronator teres, the skin of the dorsum of the hand over and adjacent to the first metacarpal bone, the dorsum of the thumb (the radial nerve being absent), both sides of the ring finger, and the radial side of the little finger.

The musculocutaneous nerve may receive a root from the seventh cervical nerve.

Anastomoses with the median nerve usually occur in the lower third of the arm, and may form an ansa; the frequency of anastomoses in this region of the arm is 8% of cases.

The musculocutaneous nerve may be doubled, unusually short, or absent.

Riche-Cannieu anastomoses (between the median and ulnar nerves in the palm of the hand) may exist in 70% of individuals. Martin-Gruber (median-ulnar nerves) anastomoses in the forearm have a reported frequency of 15%. It should be remembered that the "anastomoses" occur between the median, ulnar, radial, and musculocutaneous nerves, as well as between other nerves. These are errors in the pathway (course) of some, inappropriately placed nerve fibers. In order for these nerve fibers to get to their proper end-point, the bundle of nerves fibers leave the inappropriate trunk and join the proper nerve trunk. Both Martin-Gruber and Riche-Cannieu "anastomoses" are examples of nature's correction of nerve fibers located in inappropriate nerve pathways. Certainly a mystery, these "anastomoses". On a broader and larger scale, the brachial plexus and sacral plexuses are other examples of neuronal sorting.

Image 31A Image 31B Image 31C Image 31D Image 31E Image 31F

Image 31G Image 31H Image 31I Image 31J Image 32A

Image 32B Image 32C Image 32D Image 32E Image 32F

Image 36 Image 40 Image 46 Image 59

Variety of Anastomoses between the Musculocutaneous and Median Nerves


Anson, B.J., Ed. (1966) Morris' Human Anatomy, 12th ed., The Blakiston Division, McGraw-Hill Book Company, New York.

Appleton, A.B. (1912) A case of abnormal distribution of the n. musculocutaneous, with complete absence of the ramus cutaneous n. radialis. J. Anat. Physiol. 46:89-94.

Backhouse, K.M. (1975) Innervation of the hand. Hand 7:107-114.

Bant, A.J. (1925) Sur un cas très rare de l'innervation anormal du membre supérieur, Absence de la branche antérieur du nerf radial supplée par le nerf musculcutané. Soc. Biol. Comptes Rendus des Séances et Mémoires. 92:377-378.

Basar, R., Aldur, M.M., Celik, H.H., Yuksel, M., and A.B. Tascioglu. (2000) A connecting branch between the musculocutaneous nerve and the median nerve. Morphohlogie 84(2): 25-27.

Baur, R. (1971) Innervation des M. brachioradialis aus dem N musculocutaneous als seltene Varietät. Anat. Anz. 128:108-110.

Bergman, R.A., Thompson, S.A., Afifi, A.K. and F.A. Saadeh. (1988) Compendium of Human Anatomic Variation. Munich and Baltimore.

Broca, -. (1888) Fusion du méd. et du mus.-cut. au bras. Bull. et Mém. de la Société Anatomique de Paris 1888(2):206.

Buch, C. (1964) Zur variayion des Innervationsweise des M. biceps brachii unter Beachtung der Astabgabe vom N. musculocutaneous und vom N. medianus. Anat. Anz. 114:131-140.

Buch-Hansen, K. (1955-56) über Varietäten des Nervus medianus und des Nervus musculocutaneous und deren Beziehungen. Anat. Anz. 102:187-203.

Buch-Hansen, K. (1995). Variations of the median nerve and musculotaneous nerve and their connections. Anat. Anz. 102(9-14):187-203.

Calori, L. (1866) Delle corrispondenze del nervo musculo-cutaneo con il capo soprannumerario del bicipite bracchiale e col bracchaile interno. Mem. R. Accad. Sci. Istituto di Bologna S. 2., 6:149-155.

Calori, L. (1868) Delle anomalie piu importanti di ossa, vasi, nervi, e muscoli occorse nell'ultimo biennio facendo anatomia del corpo umano. Mem. R. Accad. Sci. Istituto di Bologna S. 2., 8:417-482.

Choi, D., Rodruguez-Niedenfuhr, M., Vasquez, T., Parkin, I., and J.R. Sanudo. (2002) Patterns of connections between the musculocutaneous and median nerves in the axilla and arm. Clin. Anat. 15(1):11-17.

Dankmeijer, J. and J.M. Waltman. (1950) Sur l'innervation de la face dorsale des doigts humains. Acta Anatomica 10:377-384.

D'Evant, T. (1895) Observations sur une anomalie de nerf perforant de Casserio. Arch. Ital. Biol. 22:162-163.

Deville, -. (1843) Anastomose du nerf musculo-cutané avec le nerf median. Bulletins et Mem. de la Société Anatomique de Paris XVIII(10):293.

Eglseder Jr., W.A. and M. Goldman. Anatomic variations of the musculocutaneous nerve in the arm. Am. J. Orthop. 26(11):777-780.

Falconer, D. and M. Spinner. (1985) Anatomic variations in the motor and sensory supply of the thumb. Clin. Orthop. 195:83-96.

Ferner, H. (1938) Der Nervus musculocutaneous, seine Verlaufsvarietaten am Oberam und deren Beziehungen zur Entwicklung eines Caput tertium bicipitis. Z. Anat. Entwicklungsgesch. 108:567-586.

Fetrow, K.O. (1970) Practical and important variations in sensory nerve supply to the hand. Hand 2:178-184.

Gegenbaur, C. (1867) Ueber das Verhältniss des N. musculocutaneus zum N. medianus. Jenaische Zeitschrift für Medicin und Naturwissenschaft. 1867: 258-263.

Gruber, W. (1881) Der Nervus radio-cutaneous externus als Substitut des Nervus ulnaris am Rücken der Hand und der Finger. Arch. Pathol. Anat. Physiol. Klin. Med. 81:27-29.

Gruber, W. (1881) über eine durch den Theilungswinkel der Arteria brachialis tretende Ansa recurrens zwischen dem Nervus musculocutaneous brachii und dem Nervus medianus beim Menschen. Arch. Pathol. Anat. Physiol. Klin. Med. 86:29-33.

Gumusburum, E. and E. Adiguzel. (2000) A variation of the brachial plexus characterized by the absence of the musculocutaneous nerve: a case report. Surg. Radiol. Anat. 22(1):63-65.

Gumusalan, Y., Yagar, F., and H. Ozan. (1998) Variant innervation of the coracobrachialis muscle and unusual course of the musculocutaneous nerve in man. Kaibogaku Zasshi 73(3):269-272.

Hartmann, H. (1888) Etude de quelques anastomoses elliptiques des nerfs du member supérior. Leur importance du point de vue de la conservation des functions sensitive-motrices aprés une section nerveuse. Mem. de la Société Anatomique de Paris 1888(2):151-165.

Henle, J. (1868) Handbuch der Systematischen Anatomy des Menschen. von Friedrich Vieweg und Sohn, Braunschweig.

Kasai, T. (1963) About the N. cutaneous brachii lateralis inferior. Am. J. Anat. 112:305-309.

Kopsch, F. (1908) Rauber's Lehrbuch der Anatomie des Menschen. Georg Thieme, Leipzig.

Laterjet, A. (1948) Testut's Traite d'Anatomie Humaine, 9th ed. G. Doin & Cie., Paris.

Kosinski, C. (1927) L'innervation cutanée de la face dorsale de la main, basée sur l'examen de 300 pieces anatomiques, avec quelques notions d'anatomie comparée. Assoc. Anatomistes Comptes Rendus 22:121-133.

Latarjet, M., Neidhart, J.H., Morrin, A. et J.M. Autissier. (1967) L'entrée du nerf musculo-cutané dans le muscle coracobrachial. Assoc. Anatomistes Comptes Rendus 138:755-765.

LeMinor, J.M. (1990) A rare variation of the median and musculocutaneous nerves in man. Arch. Anat. Histol. Embryol. 73:33-42. In French.

Leinberry, C.F. and M.A.Webhe. (2004) Brachial plexus anatomy. Hand Clin. 20(1):1-5.

Linell, E.A. (1921) The distribution of nerves in the upper limb, with reference to variabilities and their clinical significance. J. Anat. 55:79-112.

Miller, M.R., Ralston, H.J., III., and Kasahara. (1958) The pattern of cutaneous innervation of the human hand. Am. J. Anat. 102:183-217.

el-Naggar, M.M. (2001) A study on the morphology of the coracobrachialis muscle and its relationship with the musculocutaneous nerve. Folia Morphol. (Warsaw) 60(3):217-224.

Nakatani, T., Mizukami, S. and S. Tanaka. (1997) Three cases of the musculocutaneous nerve not perforating the coracobrachialis muscle. Kaibogaku Zashi. 72(3): 191-194.

Prasada, Rao P.V. and S.C. Schandhary. (2000) Communication of the musculocutaneous nerve with the median nerve. East Afr. Med. J. 77(9):498-503.

Ranschburg, P. (1917) über die Anastomosen der Nerven der oberen Extremität des Menschen mit Rücksicht auf ihren neurologische und nervenchirurgishe Bedeutung. Neurol. Centralblatt. 36:521-534.

Rao, G.R.K.H. and V.R. Rao. (1955) Musculocutaneous nerve of the arm. J. Anat. Soc. India 4:48.

Rosen, J.E., Rokito, A.S., Khabie, V., and J.D. Zuckerman. (1998) Examination of the lateral antebrachial cutaneous nerve: an anatomic study in human cadavers. Am. J. Orthrop. 27(10):690-692.

Sarikcioglu, L., Coskun, N., and Ozkau. (2001) A case of multiple anomalies in the upper limb. Surg. Radiol. Anat. 23(1):65-68.

Schaefer, E.A., Symington, J. and T.H. Bryce., Eds. (1915) Quain's Anatomy, 11th ed, Longmans, Green, and Co., London.

Stoppard, J.S.B. (1919) The variations in distribution of the cutaneous nerves of the hand and digits. J. Anat. 53:14-25.

Testut, L. (1883) (Need paper title) J. de l'Anat. et Physiol. 19:103.

Testut, L. (1884) Mémoire sur la portion brachiale du nerf musculo-cutané. Mém. l'Academie de Medécine, Paris.

Testut, -. (1884) Portion brachiale du n. musculo-cutané. Mémoires de l'Acad. de médec. de Paris 34(4).

Uzun, A., and L.L. Seelig, Jr. (2001) A variation in the formation of the median nerve: communicating branch between the musculocutaneouoss and median nerves in the man. Folia Morphol. (Warsaw) 60(2):99-101.

Versari, R. (1898) Un cas d'absence du rameau superficiel ou anteriéur du nerf radial remplacé par le nerf musculo-cutané. Arch. Ital. Biol. 30:324.

Villar, F. (1887) Anastomose du musc.-cut. et du mèdian. Bull. et Mem. de la Société Anatomique de Paris 1888(6):607-615.

Villar, F. (1888) Quelque recherches sur les anastomoses des nerfs du membre supérieur: 1) Anastomoses du musculocutané et du médian; 2) Anastomoses du médian et du cubital; 3) Anastomoses du radial et du cubital. - De leur importance au point de vue du rétablissement des fonctions à la suite des sections nerveuses. Bull. et Mém. de la Société Anatomique de Paris 1888(6):607-615.

Vitali, G. (1912) Variété bilatérale du nerf musculo-cutané et des artères du membre supérieur; biceps à trois chefs et arc axillaire chez le même individu. Arch. Ital. Biol. 57:313-314.

Yang, Z.X. Pho R.W., Khour, A.K. and B. P. Periera (1995) The musculocutaneous nerve and its branches to the biceps and brachialis muscles. J. Hand Surg. (Am) 20(4):671-675.

Section Top | Title Page
Home | Search | About Us | FAQ | Reviews | Contact Us

Anatomy Atlases is curated by Michael P. D'Alessandro, M.D. [Google+ Profile] and Ronald A. Bergman, Ph.D.

Please send us comments by filling out our Comment Form.

All contents copyright 1995-2014 the Author(s) and Michael P. D'Alessandro, M.D. All rights reserved.

"Anatomy Atlases", the Anatomy Atlases logo, and "A digital library of anatomy information" are all Trademarks of Michael P. D'Alessandro, M.D.

Anatomy Atlases is funded in whole by Michael P. D'Alessandro, M.D. Advertising is not accepted.

Your personal information remains confidential and is not sold, leased, or given to any third party be they reliable or not.

The information contained in Anatomy Atlases is not a substitute for the medical care and advice of your physician. There may be variations in treatment that your physician may recommend based on individual facts and circumstances.


This website is certified by Health On the Net Foundation. Click to verify. This site complies with the HONcode standard for trustworthy health information:
verify here.