Journal of Clinical and Diagnostic Research, ISSN - 0973 - 709X

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Dr Archana Dambal

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Dr. Archana Dambal
Department of General Medicine,
Belgaum Institute of Medical Sciences,Belgaum, Karnataka,INDIA,
On 30 Nov 2018




Dr Bhanu K Bhakhri

"The Journal of Clinical and Diagnostic Research (JCDR) has been in operation since almost a decade. It has contributed a huge number of peer reviewed articles, across a spectrum of medical disciplines, to the medical literature.
Its wide based indexing and open access publications attracts many authors as well as readers
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Dr Bhanu K Bhakhri
Faculty, Pediatric Medicine
Super Speciality Paediatric Hospital and Post Graduate Teaching Institute, Noida
On Sep 2018




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I wish all success to your journal and look forward to sending you any suitable similar article in future"



Dr Mohan Z Mani,
Professor & Head,
Department of Dematolgy,
Believers Church Medical College,
Thiruvalla, Kerala
On Sep 2018




Prof. Somashekhar Nimbalkar

"Over the last few years, we have published our research regularly in Journal of Clinical and Diagnostic Research. Having published in more than 20 high impact journals over the last five years including several high impact ones and reviewing articles for even more journals across my fields of interest, we value our published work in JCDR for their high standards in publishing scientific articles. The ease of submission, the rapid reviews in under a month, the high quality of their reviewers and keen attention to the final process of proofs and publication, ensure that there are no mistakes in the final article. We have been asked clarifications on several occasions and have been happy to provide them and it exemplifies the commitment to quality of the team at JCDR."



Prof. Somashekhar Nimbalkar
Head, Department of Pediatrics, Pramukhswami Medical College, Karamsad
Chairman, Research Group, Charutar Arogya Mandal, Karamsad
National Joint Coordinator - Advanced IAP NNF NRP Program
Ex-Member, Governing Body, National Neonatology Forum, New Delhi
Ex-President - National Neonatology Forum Gujarat State Chapter
Department of Pediatrics, Pramukhswami Medical College, Karamsad, Anand, Gujarat.
On Sep 2018




Dr. Kalyani R

"Journal of Clinical and Diagnostic Research is at present a well-known Indian originated scientific journal which started with a humble beginning. I have been associated with this journal since many years. I appreciate the Editor, Dr. Hemant Jain, for his constant effort in bringing up this journal to the present status right from the scratch. The journal is multidisciplinary. It encourages in publishing the scientific articles from postgraduates and also the beginners who start their career. At the same time the journal also caters for the high quality articles from specialty and super-specialty researchers. Hence it provides a platform for the scientist and researchers to publish. The other aspect of it is, the readers get the information regarding the most recent developments in science which can be used for teaching, research, treating patients and to some extent take preventive measures against certain diseases. The journal is contributing immensely to the society at national and international level."



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Professor and Head
Department of Pathology
Sri Devaraj Urs Medical College
Sri Devaraj Urs Academy of Higher Education and Research , Kolar, Karnataka
On Sep 2018




Dr. Saumya Navit

"As a peer-reviewed journal, the Journal of Clinical and Diagnostic Research provides an opportunity to researchers, scientists and budding professionals to explore the developments in the field of medicine and dentistry and their varied specialities, thus extending our view on biological diversities of living species in relation to medicine.
‘Knowledge is treasure of a wise man.’ The free access of this journal provides an immense scope of learning for the both the old and the young in field of medicine and dentistry as well. The multidisciplinary nature of the journal makes it a better platform to absorb all that is being researched and developed. The publication process is systematic and professional. Online submission, publication and peer reviewing makes it a user-friendly journal.
As an experienced dentist and an academician, I proudly recommend this journal to the dental fraternity as a good quality open access platform for rapid communication of their cutting-edge research progress and discovery.
I wish JCDR a great success and I hope that journal will soar higher with the passing time."



Dr Saumya Navit
Professor and Head
Department of Pediatric Dentistry
Saraswati Dental College
Lucknow
On Sep 2018




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Dr. Arunava Biswas
MD, DM (Clinical Pharmacology)
Assistant Professor
Department of Pharmacology
Calcutta National Medical College & Hospital , Kolkata




Dr. C.S. Ramesh Babu
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Best regards,
C.S. Ramesh Babu,
Associate Professor of Anatomy,
Muzaffarnagar Medical College,
Muzaffarnagar.
On Aug 2018




Dr. Arundhathi. S
"Journal of Clinical and Diagnostic Research (JCDR) is a reputed peer reviewed journal and is constantly involved in publishing high quality research articles related to medicine. Its been a great pleasure to be associated with this esteemed journal as a reviewer and as an author for a couple of years. The editorial board consists of many dedicated and reputed experts as its members and they are doing an appreciable work in guiding budding researchers. JCDR is doing a commendable job in scientific research by promoting excellent quality research & review articles and case reports & series. The reviewers provide appropriate suggestions that improve the quality of articles. I strongly recommend my fraternity to encourage JCDR by contributing their valuable research work in this widely accepted, user friendly journal. I hope my collaboration with JCDR will continue for a long time".



Dr. Arundhathi. S
MBBS, MD (Pathology),
Sanjay Gandhi institute of trauma and orthopedics,
Bengaluru.
On Aug 2018




Dr. Mamta Gupta,
"It gives me great pleasure to be associated with JCDR, since last 2-3 years. Since then I have authored, co-authored and reviewed about 25 articles in JCDR. I thank JCDR for giving me an opportunity to improve my own skills as an author and a reviewer.
It 's a multispecialty journal, publishing high quality articles. It gives a platform to the authors to publish their research work which can be available for everyone across the globe to read. The best thing about JCDR is that the full articles of all medical specialties are available as pdf/html for reading free of cost or without institutional subscription, which is not there for other journals. For those who have problem in writing manuscript or do statistical work, JCDR comes for their rescue.
The journal has a monthly publication and the articles are published quite fast. In time compared to other journals. The on-line first publication is also a great advantage and facility to review one's own articles before going to print. The response to any query and permission if required, is quite fast; this is quite commendable. I have a very good experience about seeking quick permission for quoting a photograph (Fig.) from a JCDR article for my chapter authored in an E book. I never thought it would be so easy. No hassles.
Reviewing articles is no less a pain staking process and requires in depth perception, knowledge about the topic for review. It requires time and concentration, yet I enjoy doing it. The JCDR website especially for the reviewers is quite user friendly. My suggestions for improving the journal is, more strict review process, so that only high quality articles are published. I find a a good number of articles in Obst. Gynae, hence, a new journal for this specialty titled JCDR-OG can be started. May be a bimonthly or quarterly publication to begin with. Only selected articles should find a place in it.
An yearly reward for the best article authored can also incentivize the authors. Though the process of finding the best article will be not be very easy. I do not know how reviewing process can be improved. If an article is being reviewed by two reviewers, then opinion of one can be communicated to the other or the final opinion of the editor can be communicated to the reviewer if requested for. This will help one’s reviewing skills.
My best wishes to Dr. Hemant Jain and all the editorial staff of JCDR for their untiring efforts to bring out this journal. I strongly recommend medical fraternity to publish their valuable research work in this esteemed journal, JCDR".



Dr. Mamta Gupta
Consultant
(Ex HOD Obs &Gynae, Hindu Rao Hospital and associated NDMC Medical College, Delhi)
Aug 2018




Dr. Rajendra Kumar Ghritlaharey

"I wish to thank Dr. Hemant Jain, Editor-in-Chief Journal of Clinical and Diagnostic Research (JCDR), for asking me to write up few words.
Writing is the representation of language in a textual medium i e; into the words and sentences on paper. Quality medical manuscript writing in particular, demands not only a high-quality research, but also requires accurate and concise communication of findings and conclusions, with adherence to particular journal guidelines. In medical field whether working in teaching, private, or in corporate institution, everyone wants to excel in his / her own field and get recognised by making manuscripts publication.


Authors are the souls of any journal, and deserve much respect. To publish a journal manuscripts are needed from authors. Authors have a great responsibility for producing facts of their work in terms of number and results truthfully and an individual honesty is expected from authors in this regards. Both ways its true "No authors-No manuscripts-No journals" and "No journals–No manuscripts–No authors". Reviewing a manuscript is also a very responsible and important task of any peer-reviewed journal and to be taken seriously. It needs knowledge on the subject, sincerity, honesty and determination. Although the process of reviewing a manuscript is a time consuming task butit is expected to give one's best remarks within the time frame of the journal.
Salient features of the JCDR: It is a biomedical, multidisciplinary (including all medical and dental specialities), e-journal, with wide scope and extensive author support. At the same time, a free text of manuscript is available in HTML and PDF format. There is fast growing authorship and readership with JCDR as this can be judged by the number of articles published in it i e; in Feb 2007 of its first issue, it contained 5 articles only, and now in its recent volume published in April 2011, it contained 67 manuscripts. This e-journal is fulfilling the commitments and objectives sincerely, (as stated by Editor-in-chief in his preface to first edition) i e; to encourage physicians through the internet, especially from the developing countries who witness a spectrum of disease and acquire a wealth of knowledge to publish their experiences to benefit the medical community in patients care. I also feel that many of us have work of substance, newer ideas, adequate clinical materials but poor in medical writing and hesitation to submit the work and need help. JCDR provides authors help in this regards.
Timely publication of journal: Publication of manuscripts and bringing out the issue in time is one of the positive aspects of JCDR and is possible with strong support team in terms of peer reviewers, proof reading, language check, computer operators, etc. This is one of the great reasons for authors to submit their work with JCDR. Another best part of JCDR is "Online first Publications" facilities available for the authors. This facility not only provides the prompt publications of the manuscripts but at the same time also early availability of the manuscripts for the readers.
Indexation and online availability: Indexation transforms the journal in some sense from its local ownership to the worldwide professional community and to the public.JCDR is indexed with Embase & EMbiology, Google Scholar, Index Copernicus, Chemical Abstracts Service, Journal seek Database, Indian Science Abstracts, to name few of them. Manuscriptspublished in JCDR are available on major search engines ie; google, yahoo, msn.
In the era of fast growing newer technologies, and in computer and internet friendly environment the manuscripts preparation, submission, review, revision, etc and all can be done and checked with a click from all corer of the world, at any time. Of course there is always a scope for improvement in every field and none is perfect. To progress, one needs to identify the areas of one's weakness and to strengthen them.
It is well said that "happy beginning is half done" and it fits perfectly with JCDR. It has grown considerably and I feel it has already grown up from its infancy to adolescence, achieving the status of standard online e-journal form Indian continent since its inception in Feb 2007. This had been made possible due to the efforts and the hard work put in it. The way the JCDR is improving with every new volume, with good quality original manuscripts, makes it a quality journal for readers. I must thank and congratulate Dr Hemant Jain, Editor-in-Chief JCDR and his team for their sincere efforts, dedication, and determination for making JCDR a fast growing journal.
Every one of us: authors, reviewers, editors, and publisher are responsible for enhancing the stature of the journal. I wish for a great success for JCDR."



Thanking you
With sincere regards
Dr. Rajendra Kumar Ghritlaharey, M.S., M. Ch., FAIS
Associate Professor,
Department of Paediatric Surgery, Gandhi Medical College & Associated
Kamla Nehru & Hamidia Hospitals Bhopal, Madhya Pradesh 462 001 (India)
E-mail: drrajendrak1@rediffmail.com
On May 11,2011




Dr. Shankar P.R.

"On looking back through my Gmail archives after being requested by the journal to write a short editorial about my experiences of publishing with the Journal of Clinical and Diagnostic Research (JCDR), I came across an e-mail from Dr. Hemant Jain, Editor, in March 2007, which introduced the new electronic journal. The main features of the journal which were outlined in the e-mail were extensive author support, cash rewards, the peer review process, and other salient features of the journal.
Over a span of over four years, we (I and my colleagues) have published around 25 articles in the journal. In this editorial, I plan to briefly discuss my experiences of publishing with JCDR and the strengths of the journal and to finally address the areas for improvement.
My experiences of publishing with JCDR: Overall, my experiences of publishing withJCDR have been positive. The best point about the journal is that it responds to queries from the author. This may seem to be simple and not too much to ask for, but unfortunately, many journals in the subcontinent and from many developing countries do not respond or they respond with a long delay to the queries from the authors 1. The reasons could be many, including lack of optimal secretarial and other support. Another problem with many journals is the slowness of the review process. Editorial processing and peer review can take anywhere between a year to two years with some journals. Also, some journals do not keep the contributors informed about the progress of the review process. Due to the long review process, the articles can lose their relevance and topicality. A major benefit with JCDR is the timeliness and promptness of its response. In Dr Jain's e-mail which was sent to me in 2007, before the introduction of the Pre-publishing system, he had stated that he had received my submission and that he would get back to me within seven days and he did!
Most of the manuscripts are published within 3 to 4 months of their submission if they are found to be suitable after the review process. JCDR is published bimonthly and the accepted articles were usually published in the next issue. Recently, due to the increased volume of the submissions, the review process has become slower and it ?? Section can take from 4 to 6 months for the articles to be reviewed. The journal has an extensive author support system and it has recently introduced a paid expedited review process. The journal also mentions the average time for processing the manuscript under different submission systems - regular submission and expedited review.
Strengths of the journal: The journal has an online first facility in which the accepted manuscripts may be published on the website before being included in a regular issue of the journal. This cuts down the time between their acceptance and the publication. The journal is indexed in many databases, though not in PubMed. The editorial board should now take steps to index the journal in PubMed. The journal has a system of notifying readers through e-mail when a new issue is released. Also, the articles are available in both the HTML and the PDF formats. I especially like the new and colorful page format of the journal. Also, the access statistics of the articles are available. The prepublication and the manuscript tracking system are also helpful for the authors.
Areas for improvement: In certain cases, I felt that the peer review process of the manuscripts was not up to international standards and that it should be strengthened. Also, the number of manuscripts in an issue is high and it may be difficult for readers to go through all of them. The journal can consider tightening of the peer review process and increasing the quality standards for the acceptance of the manuscripts. I faced occasional problems with the online manuscript submission (Pre-publishing) system, which have to be addressed.
Overall, the publishing process with JCDR has been smooth, quick and relatively hassle free and I can recommend other authors to consider the journal as an outlet for their work."



Dr. P. Ravi Shankar
KIST Medical College, P.O. Box 14142, Kathmandu, Nepal.
E-mail: ravi.dr.shankar@gmail.com
On April 2011

Important Notice

Case report
Year : 2011 | Month : December | Volume : 5 | Issue : 8 | Page : 1637 - 1640

Bilateral Non-Formation of Upper Trunk of the Brachial Plexus with a Unilateral Communication Between the Musculocutaneous Nerve and the Median Nerve: A Case Report

Rajan Kumar Singla, Ritika Mahajan, Rajan Sharma, Tripta Sharma

1. MBBS, MS Anatomy, Additional Professor, Department of Anatomy, Government Medical College, Amritsar – 143001, Punjab, India. 2. MBBS, MS Anatomy, Junior Resident, Department of Anatomy, Government Medical College, Amritsar – 143001, Punjab, India. 3. MBBS, MS Orthopaedics, Senior Resident, Department of Orthopaedics, Sri Guru Ram Das Institute of Medical Sciences and Research, Vallah, Sri Amritsar - 143001, Punjab, India. 4. MBBS, MS Anatomy, Prof. and Head, Department of Anatomy, Punjab Institute of Medical Sciences, Jalandhar - 144002, Punjab, India.

Correspondence Address :
Ritika Mahajan,
184, Medical Enclave, Circular Road,
Amritsar - 143001, Punjabb, India.
E-mail: sharmaritika29@ymail.com

Abstract

Variations in the brachial plexus are common and they have been reported in relation to the origin of the roots, trunks, cords, divisions and the branches. They may prove to be valuable to the orthopaedic surgeon, the radiologist, the anaesthesist, the neurosurgeon, the neurologist, and the vascular surgeons while they perform their respective procedures. In this report, a rare, bilateral non-formation of the upper trunk of the brachial plexus with a unilateral communication between the musculocutaneous nerve and the median nerve has been reported. C5 and C6 on both the sides did not join to form the upper trunk. On the right side, it separately divided into the anterior and the posterior divisions. On the left side, C5 did not give any anterior division and continued as the posterior cord after receiving the posterior division of C6. A communicating branch from the musculocutaneous nerve to the median nerve was also seen on the left side. An earlier unilateral non-formation of the brachial plexus has been reported, with an incidence of 1%, but a bilateral variation is extremely rare. Further, its ontogeny and clinical implications have been discussed in detail.

Keywords

Roots, Cords, C5, C6

How to cite this article :

Rajan Kumar Singla, Ritika Mahajan, Rajan Sharma, Tripta Sharma. BILATERAL NON-FORMATION OF UPPER TRUNK OF THE BRACHIAL PLEXUS WITH A UNILATERAL COMMUNICATION BETWEEN THE MUSCULOCUTANEOUS NERVE AND THE MEDIAN NERVE: A CASE REPORT. Journal of Clinical and Diagnostic Research [serial online] 2011 December [cited: 2019 Aug 19 ]; 5:1637-1640. Available from
http://jcdr.net/back_issues.asp?issn=0973-709x&year=2011&month=December&volume=5&issue=8&page=1637-1640&id=1800

INTRODUCTION
The brachial plexus is formed in the posterior triangle of the neck by the union of the anterior primary rami of the C5 – T1 roots. These roots join with each other to form three trunks viz the upper, the middle and the lower by the union of C5 – C6; the continuation of C7 and the union of the C8 and T1 respectively. These three trunks bifurcate into the anterior and the posterior divisions. The anterior divisions of the upper and the middle trunks unite to form the lateral cord. The anterior division of the lower trunk continues as the medial cord. The posterior divisions of all the three trunks unite to form the posterior cord. These cords give rise to different nerves for the upper limb (1).

Variations in the brachial plexus are common and they have been reported by several investigators in relation to the origin of the roots, trunks, cords, divisions and the branches.

According to Kerr (2), the variations in the formation of the trunks of the brachial plexus may be divided into two groups.

1. In the first group, there is no true cephalic or the caudal trunk, but some or all the nerves divide into the dorsal or the ventral branches and these combine to form the lateral, dorsal and medial fasciculi or no true dorsal or lateral fasciculi are formed, but the branches from the dorsal and the ventral rami of the nerves or the trunks unite to form the branches of the plexus.

2. In the second group of variations, the lateral fasciculus receives fibers from the nerves which are caudal to the 7th cervical or in which the medial fasciculus receives fibers from the nerves which are cephalic to the 8th cervical nerve.

The commonly reported variations in the brachial plexus have been in the form of:

i. A prefixed (contribution from the C4 large, T2 absent and the T1 reduced), or postfixed (contribution from the C4 absent, T2 present and the T1 enlarged) brachial plexus (1) ii. All roots joining to form a single trunk (3),(4) III. Absence of the posterior cord (4) iv. Communications between the musculocutaneous nerve and the median nerve or the absence of the musculocutaneous nerve (5) v. Three roots of the median nerve (6) vi. Communication between the median nerve and the ulnar nerve (7), etc.

One such bilateral variant pattern of the brachial plexus was observed in the present case and is being reported.

Case Report

During a routine undergraduate dissection of the upper limbs in the department of Anatomy, Government Medical College, Amritsar, Punjab, India a sixty years old female cadaver, the following observations were made.

On the right side, the C5 and the C6 roots did not join to form the upper trunk. Instead, they separately divided into the anterior and the posterior divisions. The two posterior divisions joined with each other to form a common posterior division (PD1). It received the posterior division of C7 and continued as the posterior cord (PC). The posterior cord gave the axillary nerve (AN) and then immediately after that, received the posterior division of the lower trunk (PD2 ) (root value C8, T1) and further continued as the radial nerve (RN). Thus, the axillary nerve was not receiving any contribution from C8 and T1. The anterior division of C5 and C6 joined with each other and then received the upper anterior division of C7 (UAD) to form the lateral cord (LC). The lateral cord immediately bifurcated into themusculocutaneous nerve (MCN) and the lateral root of the median nerve (LR). The lower anterior division (LAD) of C7 joined with the anterior division (AD) of the lower trunk to form the medial cord. The latter gave the medial cutaneous nerve of the arm/forearm and bifurcated into the ulnar nerve (UN) and the medial root of the median nerve (MR) (Table/Fig 1).

On the left side, C5 and C6 failed to unite and thus, no upper trunk was formed. The C5 root did not give any anterior division, but it received the posterior division of C6 (PD1) and continued as the posterior cord. The C6 root divided into the anterior and the posterior divisions. The posterior division of C6 joined the C5 root to continue as the posterior cord, while its anterior division (AD1) received the upper anterior division of C7 (AD2) to continue as the musculocutaneous nerve (MCN). The lower anterior division of C7 (AD3) continued as the lateral root (LR) of the median nerve. The lower trunk was formed as usual i.e. by the union of the C8 and the T1 roots and it divided into the anterior and the posterior divisions. Its anterior division (AD4) gave the medial cutaneous nerve of the arm and the forearm (MCFA) and the ulnar nerve (UN) and then continued as the medial root (MR) of the median nerve. The latter joined with the lateral root (LR) of the median nerve to form the median nerve (MN). The musculocutaneous nerve, after a short distance (1 cm) of its formation, gave a communicating branch (CB) to the median nerve (Table/Fig 2),(Table/Fig 3).

Thus, on both the sides, there was failure to form the upper trunk. The C5 and the C6 roots separately divided into the anterior and the posterior division on the right side, while on the left side, the C5 root did not give any anterior division, but continued as a whole as the posterior division and received the posterior division of C6. Similarly, the C7 root on both the sides, gave two anterior divisions, the upper and the lower. However, their further distribution differed on the two sides. While on the right side, the upper anterior division joined the anterior division of C5 and C6 to form the lateral cord which further gave the musculocutaneous nerve and the lateral root of the median nerve; on the left side, it joined with the anterior division of C6 to form the musculocutaneous nerve. Similarly, the lower anterior division on the right side joined with the anterior division of the lower trunk to form the medial root of the median nerve. On the left side, the lower anterior division continued as the lateral root of the median nerve. Thus, the fibers of C7 were entering the median nerve via its lateral root only on the left side, but via both the lateral and the medial roots on the right side.

Apart from this, another important variation which was seen unilaterally, was a communicating branch from the musculocutaneous nerve to the median nerve on the left side.

Discussion

Although they are uncommon, the following trunk variations have been noted in the literature.

1. In particular, the absence of the inferior trunk which is characterized by the nonunion of the C8 and the T1 nerve roots, have been reported (8),(9).

2. The absence of the middle trunk has also been observed. 3. The ventral rami of the C5, C6 and the C7 nerve roots have been found to form the superior trunk at the expense of an absent middle trunk (9).

4. Unilateral upper trunk variations which were similar to the one which was observed bilaterally in this case, have been reported (8),(9).

A study by Uysal et al (8) revealed that the absence of the superior trunk was less common (1%) than the absence of the inferior trunk (9%). In such cases, the roots which were destined to form the superior or the inferior trunks directly divided into the anterior and the posterior divisions which joined to form cords, as was seen in the present case.

Harris (10) encountered a case in which no lateral cord was formed. Instead, the C5 and the C6 roots gave two ventral branches each. One of these from both united to form the musculocutaneous nerve, while others (one each from both) descended and united with a ventral branch from C7 to form the lateral root of the median nerve. Another ventral branch from C7, along with a ventral branch of C8 and T1 formed the medial cord. He further highlighted that this type of arrangement, with the musculocutaneous nerve emanating from C5–C6 before the formation of the lateral cord, was very unusual in humans, which was seen only in some marsupials like Armadillo. Our case was similar to this on the left side, where no upper trunk was formed. C5 did not give any anterior division. The C6 root divided into the anterior and the posterior divisions. Its anterior division joined with the upper anterior division of C7 (AD3) to continue as the musculocutaneous nerve (MCN). The lower anterior division of C7 (AD3) continued as the lateral root (LR) of median nerve. So, there was no lateral cord formation on this side. Thus, sporadic cases of the non formation of the upper or lower trunk have been reported, apart from a study by Uysal et al (8). However, none of these made a mention of the bilateral non formation of the upper trunk, as was seen in the present case.

Another variation which was noted only on the left side was a communicating branch from the musculocutaneous nerve to the median nerve, which joined the latter, 1cm distal to its formation.

Li Minor (5) classified the communications between the median nerve and the musculocutaneous nerve into five types [see Table/Fig 3]:

Type-I: There was no communication between the median nerve and the musculocutaneous nerve. Type-II: The fibres of the lateral root of the median nerve passed through the musculocutaneous nerve and joined the median nerve in the middle of the arm.

Type-III: The lateral root fibres of the median nerve passed along the musculocutaneous nerve and after some distance, left it to form the lateral root of the median nerve.

Type-IV: The musculocutaneous fibres joined the lateral root of the median nerve and after some distance, the musculocutaneous nerve arose from the median nerve.

Type-V: The musculocutaneous nerve was absent and the entire fibres of the musculocutaneous nerve passed through the lateral root and the fibres to the muscles were supplied by the musculocutaneous nerve branch, out directly from the median nerve.

Thus, our case fits into type II of Li Minor’s (5) classification, whereby the median nerve was formed normally by the union of the medial and the lateral roots. Apart from this, some fibres of the lateral root passed through the musculocutaneous nerve and joined the median nerve in the middle of the arm.

ONTOGENY
Harrison (11) established two essential factors in the development of different components of the limbs by his experiments on amphibian larvae i.e.

1. The nerves which take part in the innervations of a limb are determined by the position and the width of a limb bud. A limb bud which is transplanted to some other part of the body acquires a complete system of nerves, which is supplied by the region in which the limb is implanted.

2. The distribution of the nerves within a limb is determined by its own component structures. The segregation of the developing structure within the limb has a directive action upon the growing nerve fibres and this determines their grouping into definite characteristic bundles.

At an early developmental stage, the plexus is rectangular, then it becomes trapezoidal and finally it forms a triangular shape (12).

Although it is unclear why neuronal processes assemble to form a mixed nerve, in this complex developmental event, there are multiple possibilities for the route which is taken by the developing axons and thus, for their arrival at the main trunk. Once formed, any developmental differences would obviously persist postnatally (13). As the guidance of the developing axons is regulated by the expression of chemoattractants and chemorepulsants in a highly coordinated site specific fashion, any alterations in signaling between the mesenchymal cells and the neuronal growth cones can lead to significant variations (14).

In the present case, it seems to be the overexpression of the chemoattractants/ repulsants, leading to the separation of the C5 and the C6 roots, presenting as the non formation of the upper trunk and the formation of the double anterior divisions of the C7 roots.

PHYLOGENY
Miller (15) summarized the differences in the normal patterns of the roots, trunks, divisions, cords and the branches of the brachial plexus in different vertebrates. According to him, no trunk formation is seen in amphibians, reptiles and dogs. So, our case partially fits into this category as the upper trunk was not formed on both the sides.

A communicating branch from the musculocutaneous nerve to the median nerve as was seen in the left limb of the present case is usually seen in dogs (16).

CLINICAL IMPORTANCE
For a surgeon, to have the variational patterns of the brachial plexus at his finger’s ends is essential in the light of not only the frequency with which a surgery is performed in the axilla and the surgical neck of the humerus (8),(17) and the rapid development of microsurgical techniques (12), but also to give an explanation when he encounters an incomprehensible clinical sign (7).

Apart from the surgeon, the brachial plexus variations are of interest not only to the radiologists who interpret the plain and computerized imagings and MRI and the anaesthesiologists who place needles in the neck to administer anaesthetic blocks, but also to the neurosurgeons, neurologists, vascular surgeons and the orthopaedic surgeons (18),(19).

While Ongoiba et al (20) laid stress on the fact that a variable brachial plexus could fail the brachial plexus loco-regional anaesthesia, Sargon et al (21) and Uzun and Seelig (22) commented that such a brachial plexus was more prone to injury in radical neck dissections and in other surgical operations of the axilla.

The present variant of the brachial plexus may give incomprehensible clinical signs in Erb’s palsy. Since the upper trunk is not formed, thechances of involvement of C6 are remote. Moreover, on the left side, since C5 did not give any anterior division and continued as the posterior division only, the C6 root would face the main brunt of the injury, thus causing Erb’s palsy. Thus, the clinical picture would be of injury to C6, but sparing C5, which would be extremely confusing if the clinician was not familiar with such variations. Also, since C5 was totally going as the posterior division, if at all it was involved in the injury, it would affect the muscles which were supplied by the posterior cord or its branches i.e. radial and axillary etc only and not the muscles which were supplied by the branches of the lateral cord. This would further complicate the clinical picture.

The knowledge of a common variation like the communication between the musculocutaneous nerve and the median nerve may prove to be valuable in the traumatology of the shoulder joint as well as in relation to the repair operations (16),(23),(24). Also, it may be correlated to the entrapment syndromes of the musculocutaneous nerve in which a part of the median nerve also passes through the coracobrachialis and may exhibit the symptoms which are similar to those which are encountered in median nerve neuropathy as in the carpal tunnel syndrome (16).

References

1.
Berry MM, Standring SM, Bannister LH. Nervous System. In: Williams PL, Bannister LH, Berry MM, Collins P, Dyson M, Dussek JE, et al, editors. Gray’s Anatomy – The Anatomical Basis of Medicine and Surgery. 38th ed. Edinburgh: Churchill Livingstone; 1995; 1266-69.
2.
Kerr AT. The brachial plexus of nerves in man; the variations in its formation and branches. Am J Anat 1918;23(2): 285-395.
3.
Singer M. Human brachial plexus united into a single cord : description and interpretation. Anat Rec 1932; 54 : 411-19.
4.
Pandey SK, Kumar S. Anomalous formation of the brachial plexus cords and the median nerve. J Anat Soc Ind 2004;53(1): 31
5.
Li Minor JM. A rare variant of the median and the musculocutaneous nerves in man. Arch Anat Histol Embryol 1992 ; 73 : 33-42.
6.
Chauhan R and Roy TS. Communication between the median and the musculocutaneous nerves: A case report. J Anat Soc Ind 2002; 51(1): 72-5.
7.
Gumusburun E, Adiguzel E. A variation of the brachial plexus characterized by the absence of musculocutaneous nerve : A case report. Surg Radiol Anat 2000; 22(1) : 63-5.
8.
Uysal II, Seker M, Karabulut AK, Buyukmumcu M, Ziylan T. Brachial plexus variations in human fetuses. Neurosurg 2003 ; 53 : 676-84.
9.
Matejcik V. Anatomic variations in the brachial plexus trunks and the nerve roots. Rozhl Chir. 2003 ; 82(9) : 456-59.
10.
Harris W. The true form of the brachial plexus and its motor distribution. J Anat Physiol 1904 ; 38 : 399-422.
11.
Harrison (1907). Cited by Keibel NZ and Mall FP. Nerves of the Arm and Leg. In: Manual of Human Embryology, Vol. 2, 1st Edn, Philadelphia and London, J.B. Lippincott Co, , 1912; 122-28.
12.
Andrzejczak A, Kwolczak A, Nosek R, Ciszek B, Gradowska UW, Brzozowska M. Brachial plexus vascularization – a preliminary study. Acta clinica 2001; 2 : 111-16.
13.
Brown MC, Hopkins WG, Keynes RJ. Axon Guidance and Target Recognition. In: Essentials of Neural development. Cambridge, Cambridge University Press , 1991; 46-66.
14.
Sannes HD, Reh TA, Harris WA. Axon Growth and Guidance. In: Development of Nervous System. New York, Academic Press 2000; 189-97.
15.
Miller RA. Comparative studies on the morphology and the distribution of the brachial plexus. Am J Anat 1932; 54(1) : 143-66.
16.
Rao PPV, Chaudhary SC. Communication of the musculocutaneous nerve with the median nerve. East African Med J 2000; 77(9): 498-503.
17.
Leffert RD. Brachial Plexus Injuries. In : Anatomy of the Brachial Plexus. New York, Churchill Livingstone, 1985; 384.
18.
Makhoul RG, Machleder HI. Developmental anomalies at the thoracic outlet : An analysis of 200 consecutive cases. J Vasc Surg 1992; 16: 534-45.
19.
Collins JD, Shaver ML, Disher AC, Miller TQ. Compromising abnormalities of the brachial plexus as displayed by magnetic resonance imaging. Clin Anat 1995; 8 :1-16.
20.
Ongoiba N, Destrieux C, Koumare AK. Important variations in the brachial plexus. Morphologie 2002; 86(273) : 31-4.
21.
Sargon MF,Uslu SS, Celik HH, Aksit D. A variation of the median nerve at the level of the brachial plexus. Bull Assoc Anat (Nancy) 1995; 79(246): 25-6.
22.
Uzun A, Seelig LL. A variation in the formation of the median nerve: the communicating branch between the musculocutaneous and the median nerves in man. Folia Morphol (Warsz) 2007; 60(2) : 99-101.
23.
Benjamin A, Hirschowitz D, Arden GP, Blackburn N. Doppelosteotomie am schultergelenk. Orthopade 1981; 10 : 245-49.
24.
Seradge H, Orme G. Acute irreducible anterior dislocation of the shoulder. J Trauma 1982; 22 : 330-32.

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