Download Case report Three lateral roots of median nerve: a case report

Page 1 of 2
Anatomy
Case report
Three lateral roots of median nerve: a case report
S Surendran, NB Satheesha, D Reghunathan, BM George, SS Rao
Introduction
Introduction
The median nerve is formed by the
union of a lateral and a medial root
from the lateral and medial cords
of brachial plexus. Reports on the
existence of variations in the formation, branching and communication
of median nerve are seen in the literature. However, there are very few
reports on the involvement of two
additional lateral roots in the formation of the median nerve. Such variations are of considerable importance
for surgeons, physiotherapists and
other clinicians. The details regarding
the formation of the median nerve,
developmental considerations and
its importance have been discussed
here.
Case report
Apart from the normal roots, two
additional lateral roots were given
off from the lateral cord at the level of
the second part of the axillary artery.
These roots then coursed super icial
to the axillary artery from the lateral to medial side to join the medial
root, on the medial side of the axillary
artery. The medial root then crossed
on to the lateral side of the axillary
artery to join the lateral root to form
the median nerve. The rest of the
course of the median nerve was found
to be normal.
Conclusion
Surgeons during surgeries of the
axilla and physiotherapists during
rehabilitation would require knowledge of such variations in the axilla,
along with use for other clinicians
too.
The cords and branches of the brachial plexus are one of the major
contents of the axilla, which lie in
relation to the axillary artery (AA).
Classically, the median nerve (MN)
is formed by the joining of a single
lateral root and a single medial root,
given off from the lateral and medial
cords of brachial plexus respectively. The lateral and medial roots
of MN are located on respective
sides of AA. The medial root of the
MN (MRMN) crosses the AA supericially, to reach its lateral side and
joins the lateral root (LRMN) to form
the MN. This results in the formation
of MN lateral to the AA. Then, until
the lower third of the arm, the MN
runs on the lateral aspect of brachial
artery, where it crosses the medial
side of the brachial artery and later
becomes a content of the cubital
fossa. Variations in the branching
pattern of MN and its communications with musculocutaneous1–6 and
ulnar nerves7,8, splitting of the nerve
*Corresponding author: S Surendran
E-mail: [email protected]
Department of Anatomy, Melaka Manipal
Medical College, Manipal University, Manipal
576 104, Karnataka, India
are some to mention, that have been
reported by many authors. This
paper reports a case of three lateral
roots of the MN.
Case Report
During a routine dissection of the
axilla in an ~50-year-old male
cadaver, three lateral roots and one
medial root were observed to be
involved in the formation of the MN.
The two additional lateral roots
(LRMN 1 and LRMN 2) of MN were
given off from the lateral cord of brachial plexus (close to second part of
AA). Both these roots coursed over
to the medial side of the AA, super icial to it (Figure 1). These roots then
joined the medial root on the medial
side of the AA. The medial root then
crossed on to the lateral aspect of the
AA, where it joined with the third lateral root (LRMN 3) of MN given off
from the lateral cord of the brachial
plexus, to form the MN. The rest of
the course of the MN was found to be
normal.
LRMN 3
LRMN 2
LRMN 1
MN
AA
MRMN
Figure 1: The additional roots of median nerve. (AA, Axillary artery; LRMN 1,
Lateral root of median nerve 1; LRMN 2, Lateral root of median nerve 2;
LRMN 3, Lateral root of median nerve 3; MN, Median nerve; MRMN, Medial root
of median nerve).
Licensee OA Publishing London 2013. Creative Commons Attribution Licence (CC-BY)
F
: Surendran S, Satheesha Nayak B, Reghunathan D, George BM, Rao Sirasanagandla S. Three
lateral roots of median nerve: a case report. OA Case Reports 2013 Sep 10;2(10):97.
CompeƟng interests: none declared. Conflict of interests: none declared.
All authors contributed to the concept on, design, and preparaƟon of the manuscript, as well as read and approved the final manuscript.
All authors abide by the AssociaƟon for Medical Ethics (AME) ethical rules of disclosure.
Abstract
Page 2 of 2
Discussion
MN is one among the nerves that
have been studied extensively and
reported for the different kinds of
formation, variations in communications9–11 and altered course in
the arm. During the search for literature, there were reports found
which stated the communication to
the MN from the musculocutaneous
nerve12–14. There were also reports
regarding the ulnar nerve communications1–6 to the MN. The MN is of considerable importance both from the
clinical and as well as surgical point
of view. This importance is due to
the variant communications it shows
in its course. Even though there are
many case reports regarding its variant communications, it is seen that
the additional roots involved in the
formation of MN still remains to be a
rare case found. There were a couple
of reports regarding the existence of
two roots in the formation of MN14,15.
During development, around the
5th week, the mesodermal somites
that are responsible for the development of the upper and lower limb
muscles, migrate into the developing upper and lower limbs. The
somites normally have individual
spinal nerves for themselves. The
root values of nerves supplying the
developed muscles of the upper
limb demonstrate that the muscles
of the upper limb develop from multiple somites. Initially, the appropriate spinal nerves innervate into the
mesenchyme as isolated ventral and
dorsal branches. Soon after entering,
these branches unite and form bulky
ventral and dorsal nerves. Hence the
radial nerve, which is formed by the
joining of dorsal branches, supplies
the extensor muscles. The median
and ulnar nerves that are formed
by the joining of ventral branches,
supply the lexor muscles. The
development of the musculature of
the upper limb from different somites
results in the complicated structure
of the brachial plexus and any kind of
variation from the normal formation
of these muscles could possibly result
in a variation in the formation of the
nerves supplying those muscles. Even
a slight change in the course of migration of the myotomes could result in
changing the normal pattern of formation of brachial plexus. Since these
variations are developmental, these
could be known only when there is
a particular symptom with respect
to the variation or in conditions with
respect to the structure in relation to
such variations. These reports add
to the knowledge of the variations in
the formation of a MN and a better
expectant approach for a surgeon or
a clinician dealing with the contents
of axilla.
Conclusion
Knowledge of such variations in the
formation of MN would be of considerable importance for anatomists,
radiologists, surgeons and clinicians,
when they handle cases involving
AA or MN or both, owing to the close
proximity of the additional roots of
MN with the AA.
References
1. Basar R, Aldur MM, Celik HH, Yuksel M,
Tascioglu AB. A connecting branch
between the musculocutaneous nerve
and the median nerve. Morphologie. 2000
Sep;84(266):25–7.
2. Buch-Hansen K. Variations of the
median nerve and the musculocutaneous
nerve and their connections. Anat Anz.
1955 Nov;23;102(9–14):187–203.
3. Datta I, Ghoshal AK, Ray A. Complete
absence of lateral root of median nerve
and communication of musculocutaneous nerve with median nerve - a case
report. J Indian Med Assoc. 2011
May;109(5):341–2.
4. Ozturk NC, Uzmansel D, Ozturk H. An
unreported pattern of musculocutaneous and median nerve communication
with multiple variations of biceps brachii: a case report. Surg Radiol Anat. 2010
Nov;32(9):887–90.
5. Patil ST, Meshram MM, Kasote AP, Kamdi
NY. Formation of median nerve from single root on left side and communicating
branch from median nerve to musculocutaneous nerve on right side. Morphologie.
2012 Aug;96(313):51–4.
6. Prasada Rao PV, Chaudhary SC.
Communication of the musculocutaneous nerve with the median nerve. East Afr
Med J. 2000 Sep;77(9):498–503.
7. Sarikcioglu L, Sindel M, Ozkaynak S,
Aydin H. Median and ulnar nerve communication in the forearm: an anatomical
and electrophysiological study. Med Sci
Monit. 2003 Sep;9(9):BR351–6.
8. Amoiridis G, Bizas E, Ameridou I. The
frequency of ulnar to median nerve anastomosis (Marinacci communication). Clin
Neurophysiol. 2006 Aug;117(8):1881–2;
author reply 2–3.
9. Bonnel F. Microscopic anatomy of the
adult human brachial plexus: an anatomical and histological basis for microsurgery. Microsurgery. 1984;5(3):107–18.
10. Lee HY, Chung IH, Sir WS, Kang HS, Lee
HS, Ko JS, et al. Variations of the ventral
rami of the brachial plexus. J Korean Med
Sci. 1992 Mar;7(1):19–24.
11. Uzun A, Seelig LL, Jr. A variation in the
formation of the median nerve: communicating branch between the musculocutaneous and median nerves in man. Folia
Morphol (Warsz). 2001;60(2):99–101.
12. Standring S, Ellis H HJ, Johnson D,
Williams A. Gray’s Anatomy. 39 ed.
Elsevier: Churchill, Livingstone.
13. Das S, Paul S. Anomalous branching
pattern of lateral cord of brachial plexus.
Int J Morphol. 2005;23(4):289–92.
14. Saeed M, Rufai AA. Median and musculocutaneous nerves: variant formation and distribution. Clin Anat. 2003
Sep;16(5):453–7.
15. Sargon MF, Uslu SS, Celik HH, Aksit D.
A variation of the median nerve at the
level of brachial plexus. Bull Assoc Anat
(Nancy). 1995 Sep;79(246):25–6.
Licensee OA Publishing London 2013. Creative Commons Attribution Licence (CC-BY)
F
: Surendran S, Satheesha Nayak B, Reghunathan D, George BM, Rao Sirasanagandla S. Three
lateral roots of median nerve: a case report. OA Case Reports 2013 Sep 10;2(10):97
CompeƟng interests: none declared. Conflict of interests: none declared.
All authors contributed to the concept on, design, and preparaƟon of the manuscript, as well as read and approved the final manuscript.
All authors abide by the AssociaƟon for Medical Ethics (AME) ethical rules of disclosure.
Case Report