Absence Of Musculocutaneous Nerve Research Articles

Anatomical study of Variations of Median Nerve and Musculocutaneous Nerve in the Arm

Background: The variations related to the median nerve and musculocutaneous nerve are relatively less
 common. The variations may have potential clinical implications especially during surgeries and nerve
 blocks.
 Materials and Method: The routine dissection of 50 adult cadavers including 42 males and 8 females in
 the Department of Anatomy during undergraduate training was carried out to detect the variations in the
 structure, formation and relation of Median nerve and musculocutaneous nerve.
 Results and Findings: There was a variation observed in the formation of median nerve in three adult
 cadavers. In three male cadaver, there was unilateral variation in the formation of the median nerve by more
 than two roots . However, in each of these cadavers the distribution of the median nerve was normal in arm,
 forearm and palm. There was normal pattern of formation, relation and course of Median nerve in rest of the
 cadavers. Absence of musculocutaneous nerve, and nerve not piercing coracobrachialis, and communication
 between median and musculocutaneous nerve was found. Photographs of abnormalities were taken for
 proper documentation of the variations.
 Conclusion: These variations have been explained by some embryological flats available. These variations
 of formation of median nerve are clinically important for physicians, surgeons and anesthetists because
 symptoms of median nerve compression due to these variations are often confused with radiculopathy
 and carpal tunnel syndrome. The knowledge of variations of musculocutaneous nerve is important to the
 surgeons and anesthetists’ for carrying out surgical procedures and nerve blocks in axilla and arm.

Unilateral absence of musculocutaneous nerve with bilateral variation in the formation of the median nerve

Anatomical variations of the brachial plexus and its nerves are common. In this case, during a routine cadaver dissection, we encountered different variations of the brachial plexus. On the right side, there was an absence of musculocutaneous nerve (MCN) and the two roots of the median nerve (MN) united in the upper arm despite the axilla. Flexor muscles of the right arm, i.e., coracobrachialis, biceps brachii and brachialis, were innervated directly by the two different branches from the lateral cord. On the left side, the MCN was present and distributed as usual, but the MN received additional contributions from the lateral cord. Variations in the peripheral nerves are usually prone to iatrogenic injuries and brachial plexus block failure. Precise knowledge of such variations helps clinicians in the correct interpretation of unusual clinical findings, nerve conduction tests and imaging. This case report also shows the importance of vigilant anatomical dissection.

Absence of musculocutaneous nerve bilaterally with variant motor innervations of flexors of arm

ABSTRACT Variations of the brachial plexus are of great interest for anatomists, clinicians and surgeons, in that they may be incorporated in day to day practice. A middle aged female cadaver on routine dissection showed absence of the musculocutanaous nerve bilaterally. The anterior compartment of both arms were supplied by the median nerve. The median nerve after supplying the coracobrachialis and biceps, gave a common branch for the brachialis and lateral cutaneous nerve of the forearm. The present case may be noted for its clinical and surgical significance in the variations of brachial plexus which can be useful for diagnostic and therapeutic purposes. Copyright © 2014, Indian Journal of Medical Specialities. Published by Reed Elsevier India Pvt. Ltd. All rights reserved.

Absence of Musculocutaneous Nerve Associated with Variations of Distribution Patterns of the Median Nerve

Las variaciones en el plexo braquial y los patrones de distribucion de sus ramos no son infrecuentes. Un ramo comunicante, que es la variante mas frecuente, a menudo surge desde el nervio musculocutaneo al nervio mediano. Sin embargo, los ramos que surgen del fasciculo lateral del plexo braquial y nervio mediano en vez de nervio musculocutaneo son muy raros. La descripcion detallada de las anomalias es importante para procedimientos quirurgicos. En nuestro caso el nervio musculocutaneo estaba ausente, un ramo del fasciculo medial inervo el musculo coracobraquial y dos ramos del nervio mediano inervaron los musculos biceps y braquial, respectivamente. Por otra parte, el nervio mediano origino al nervio cutaneo antebraquial lateral. Este informe proporciona evidencia de algunas variaciones anatomicas utiles para cirujanos, anestesistas y neurologos durante la practica clinica.

Variations in innervation of muscles in anterior compartment of arm - a cadaveric study.

Study was undertaken to observe the variation in the innervation of muscles in the front of arm. The results were compiled. Embryological basis and clinical applications of encountered variations were tried to explain with the help of available literature. Thirty upper limbs from fifteen cadavers were dissected to observe the contents of front of arm. Musculocutaneous nerve, median nerve and innervation of the muscles of front of arm were observed. Variations were observed in 13% of cases. Commonly seen variation was the absence of musculocutaneous nerve and innervation of muscles of front of arm by branches of median nerve. This variation was seen bilaterally in 3.3% of cases and unilaterally in 6.6% cases. Bilateral presence of this variation in one out of fifteen cadavers is rare finding. Variation is more common on right side as compared to the left side. Bilateral absence of musculocutaneous nerve and innervation of muscles of front of arm from the branches of median nerve is a rare variation. Knowledge of such anatomical variations is of interest to the anatomist and clinician alike. Variations assume significance during surgical exploration of the axilla and can even fail nerve block of infraclavicular part of brachial plexus. Surgeons who perform procedures involving neoplasm or repairing trauma need to be aware of these variations.

Musculocutaneous Nerve absence; a research study in sixty upper limb specimens

Absence of musculocutaneous nerve was observed during study of 60 dissected upper limb specimens. The area of innervation was supplied by median nerve. Knowledge of this anatomical variation is of clinical significance to neurologists, traumatologists and surgeons as injury to median nerve in this case would lead to unexpected paralysis of flexor muscles of arm and hypoaesthesia of lateral surface of forearm.

Absence of Musculocutaneous Nerve: Embryological Basis

Variation of brachial plexus characterized by the absence of musculocutaneous nerve in right arm was found during routine dissection of a 54 year old male cadaver. After giving lateral pectoral nerve, rest of the lateral cord continued as lateral root of median nerve. An unusual branch was arising from lateral cord which crossed the axillary artery anteriorly and then divided into two branches. One of these branches joined ulnar nerve and other medial root of median nerve. All the muscles of front of arm were supplied by branches of median nerve. These variations are important for the anesthetists, surgeons, neurologists during surgery and for anatomists during dissection in the region of axilla. DOI: http://dx.doi.org/10.3126/ajms.v3i2.6626 Asian Journal of Medical Sciences 3(2012) 21-24

Variant Median and Absent Musculocutaneous Nerve

Three roots of Median nerve and absence of Musculocutaneous nerve was encountered unilaterally on right side during routine undergraduate dissection training at Padmashree Dr. D.Y. Patil Medical College, Pimpri, Pune. Median nerve gave four branches in the arm. It pursued normal course and distribution in forearm and hand. Anatomical knowledge of the variations about Root, Trunk, Divisions and Cords of Brachial plexus along with the branches arising from these structures which supply pectoral girdle and upper extremity is extremely important while surgical exploration and administration of neuromuscular blocks in the Axillary region. This knowledge also proves helpful while planning reconstructive flap surgeries and treatment of fractures at the upper end of Humerus.

Absence of musculocutaneous nerve with variations in course and distribution of the median nerve

Variations in the brachial plexus and its terminal branches are not uncommon. A communicating branch arising from the musculocutaneous nerve to the median nerve is a frequent variation, but complete merging of musculocutaneous nerve into the median nerve is very rare. Here, we observed variations in the origin, course and distribution of the median nerve in the left upper limb. The musculocutaneous nerve was absent. The median nerve was formed in the upper part of the arm, in front of the brachial artery. The median nerve supplied the biceps, coracobrachialis and brachialis muscles and gave the lateral cutaneous nerve of the forearm. The present report provides evidence of variation in important nerves of the anterior compartment of the arm.

Unusual variation of the lateral cord of brachial plexus and absent musculocutaneous nerve- a case report.

Fusion of lateral cord of brachial plexus with median nerve and absence of musculocutaneous nerve was found in the right upper limb of an adult male cadaver during routine dissection in the Department of Anatomy, College of Medical Sciences, Bharatpur, Nepal. The fusion was noted to be proximal to the insertion of coracobrachialis muscle. The finding was noted after thorough and meticulous dissection of the upper limbs of both sides (axilla, arm, forearm and palm). The muscles of the front of the arm, namely coracobrachialis, biceps brachii and medial part of brachialis were found to be innervated by branches from the median nerve. No other abnormality was detected.

About the absence of musculocutaneous nerve

Introduction: Musculocutaneous nerve (C5-7) derives (90,5%) from the lateral cord of brachial plexus at the level of lateral border of pectoralis minor [1]. MC nerve pierces the coracobrachialis muscle and descends between the biceps brachii and brachialis to the lateral side of the elbow and terminates as the lateral cutaneous nerve of forearm. It supplies the biceps brachi, the coracobrachialis and the brachialis. Its terminal branch is purely sensory. Variations in the MC nerve course, distribution and termination have been reported and variably classified [2]. The most frequent variations are the presence of communicating branches with the median nerve [3] and the nerve not perforating the coracobrachialis muscle [4]. Total absence of MC nerve is less frequent (1.4 to 15%) [5]. Materials and Methods: 25 upper limbs from 13 cadavers were dissected. A skin incision was performed on deltopectoral groove and arm midline. Two fasciocutaneous flaps were raised, exposing brachial plexus and MC nerve. Results: In two specimens MC was not demonstrable. In these cases, the nerve branches to the coracobrachialis muscle and the lateral cutaneous forearm nerve originated directly from the median nerve. Conclusion: during embryogenesis MC nerve is derived relatively late, thus its absence may correspond to an incomplete differentiation of the brachial plexus. We believe this anatomical variation noteworthy because clinical procedures as plexus block or Latarjet’s procedure may be affected from MCN anomalies.

Absence of musculocutaneous nerve and accessory head of biceps brachii: a case report

ABSTRACTDuring dissection of a 55-year-old female cadaver, we observed that three nerve roots contributed to the formation of Median nerve in her right upper limb. Along with this variation, absence of Musculocutaneous nerve was noticed. The muscles of front of arm i.e. Biceps Brachii, Brachialis and Coracobrachialis received their nerve supply from Median nerve. The Lateral cutaneous nerve of forearm was derived from Median nerve. Also an accessory head of Biceps Brachii muscle was present in the right arm of the same cadaver. It is extremely important to be aware of these variations while planning a surgery in the region of axilla or arm as these nerves are more liable to be injured during operations.

Absence of musculocutaneous nerve and accessory head of biceps brachii: a case report

During dissection of a 55-year-old female cadaver, we observed that three nerve roots contributed to the formation of Median nerve in her right upper limb. Along with this variation, absence of Musculocutaneous nerve was noticed. The muscles of front of arm i.e. Biceps Brachii, Brachialis and Coracobrachialis received their nerve supply from Median nerve. The Lateral cutaneous nerve of forearm was derived from Median nerve. Also an accessory head of Biceps Brachii muscle was present in the right arm of the same cadaver. It is extremely important to be aware of these variations while planning a surgery in the region of axilla or arm as these nerves are more liable to be injured during operations.

Absence of musculocutaneous nerve: Two case reports

Anomalies of the brachial plexus including its terminal branches as well as the course and distribution of the nerves in the upper limb have been reported in the literature. Two cases of absent musculocutaneous nerve from the lateral cord of the brachial plexus encountered during routine gross anatomical dissection are reported. The median nerve took over the area of supply of the musculocutaneous nerve by giving both the muscular and sensory branches. Out of 24 upper limbs dissected, the musculocutaneous nerve was found to be absent in 8% of the cases. The clinical implications of the absent musculocutaneous nerve and its etiology in light of its development is discussed.