Download Case Report Tendinous flexor carpi radialis: a case report

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Anatomy
Case Report
Tendinous flexor carpi radialis: a case report
Introduction
Flexor carpi radialis is a muscle of
the superficial group of muscles, in
the anterior compartment of the
forearm. Normally, it takes origin
from the medial epicondyle of the
humerus and is inserted into the pal­
mar aspect of the base of the second
metacarpal bone and gives off a slip
to the third metacarpal in the same
aspect. This study reports a case of
tendinous flexor carpi radialis.
Case report
Here we present a case with most of
the flexor carpi radialis (except for a
few muscle fibres close to the origin)
being replaced with the tendinous
portion.
Discussion
The action of flexor carpi radialis
is in combination with the other
muscles acting at the wrist joint.
Some of the actions include flexion,
abduction and circumduction that
involve the flexor carpi radialis. Any
change in the normal anatomy of the
muscle would affect the normal
actions at the wrist.
Conclusion
The knowledge regarding the varia­
tions in this muscle would prove bene­
ficial to physiotherapists and, also,
clinicians. Other main clinical impli­
cations of flexor carpi radialis are in
grafts. The clinical and applied aspects
have been discussed in this report.
Introduction
There are eight muscles in the ante­
rior compartment of the forearm, five
*Corresponding author
Email: [email protected]
Department of Anatomy, Melaka ­
Manipal
­Medical College, Manipal University, ­Karnataka,
India
in the superficial and three in the deep
group. Of them, the flexor carpi radia­
lis (FCR) is a superficial muscle, tak­
ing origin from the ventral surface of
the medial epicondyle of the humerus,
from the common flexor tendon. It
runs distally, towards the radial side
of the forearm to get inserted into
the palmar aspect of the base of the
second metacarpal bone and through
a slip to the third metacarpal bone.
The muscle becomes tendinous half­
way through its insertion. There could
be additional slips given off to the
fourth metacarpal too1. This muscle is
involved in the flexion at the wrist joint
along with the flexor carpi ulnaris. It is
involved in abduction at the wrist joint
when acting along with extensor carpi
radialis longus and brevis. The actions
at the wrist joint are of utmost impor­
tance in our day-to-day activities and
variations, as the one mentioned in
this report could possibly result in a
change in the efficiency of the actions
at the wrist joint. This study reports a
case of most FCR being replaced by the
tendinous portion.
Case report
During a routine anatomy dissec­
tion of the front of the forearm, in an
approximately 50-year-old cadaver,
the FCR was seen to have a short mus­
cle belly close to the origin and the
rest of its length was tendinous till
insertion (Figure 1). The muscle belly
usually converts into a tendon once it
reaches halfway distally, on its course
towards insertion into the meta­
carpals. In this case, the total length
of the FCR from the point of origin
to insertion was calculated to be
284 mm. The muscle part when meas­
ured was a mere 84 mm. The muscle
belly when seen from its deeper aspect
had a tendinous structure. Hence, the
initial muscular portion was only
present in the superficial aspect and
the FCR on its entire length was ten­
dinous in its deep aspect. There are
various reports stating the existence
of FCR brevis2–6, but there were no
reports of tendinous FCR reported
so far based on our literature search,
which makes this variant case of FCR
the first to be reported.
Discussion
The involvement of FCR at the move­
ment of the wrist joint is well-known
and the normal anatomy of it is well
documented. The action of FCR is in
combination with the other muscles
acting at the wrist joint. Some of the
actions include flexion, abduction and
circumduction that involve the FCR.
The functional importance of FCR
is also well-known. It is reported to
possess half the strength when com­
pared with the flexor carpi ulnaris.
According to Friden et al.7, the flexor
carpi ulnaris muscle fibres are more
prone to variation in their length in
comparison with the muscle fibres of
the FCR. This might be a point to say
that the variation explained in this
case report is one of the rarest cases,
and we did not come across any such
variation being reported so far.
Structural implications
One of the main clinical implications
of FCR is in grafts. The uses of ten­
dons of the FCR in various reconstruc­
tive surgeries that involve the wrist
and hand have been well-­documented
owing to its dispensability8–13. The
common use of the tendon of FCR
is in the interpositional graft in the
treatment of arthritis of the first
carpometacarpal joint and also in
opponensplasty9,10, in which, part of
the tendon or the entire tendon may
be used. In cases, such as the one
­presented here, the increase in length
Licensee OA Publishing London 2013. Creative Commons Attribution License (CC-BY)
For citation purposes: Reghunathan D, Satheesha Nayak B, Surendran S, Kumar N, Rao Sirasanagandla S. Tendinous flexor carpi
radialis: a case report. OA Case Reports 2013 Sep 10;2(10):96.
Competing interests: none declared. Conflict of interests: none declared.
All authors contributed to the conception, design, and preparation of the manuscript, as well as read and approved the final manuscript.
All authors abide by the Association for Medical Ethics (AME) ethical rules of disclosure.
Abstract
D Reghunathan, B Satheesha Nayak, S Surendran*, N Kumar, S Rao Sirasanagandla
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Figure 1: Picture showing the variant flexor carpi radialis muscle. (FCR–M/T, flexor carpi radialis muscle and tendon;
FDS, flexor digitorum superficialis; FCU, flexor carpi ulnaris; BR, brachioradialis; RA, radial artery; BA, bicipital ­aponeurosis).
of the tendon might possibly provide
more connective tissue if required in
certain cases, where the entire ten­
don is used. On the contrary, if there
is partial use of the tendon done, the
reduced bulk of the muscle fibres
in this case, might not be able to
provide the support as by the nor­
mal stature of FCR. The knowledge
of such variant formations of FCR
could help physiotherapists plan
better while helping in the rehabili­
tation post reconstructive surgeries,
­involving the tendon of FCR for the
surgery.
Biomechanical implications
There could also be a possibility of
alterations in the biomechanics at
the wrist joint due to the imbalanced
structure of the FCR. The decrease
in the muscle fibres could possibly
lead to the reduction in the effective
action of the FCR. During flexion at
the wrist, the action is brought about
by the FCR along with the flexor carpi
ulnaris. According to Werner et al.14,
the wrist FCR forces were calculated
and they found that the peak FCR
forces were seen in circumduction
action and in other actions such as
extension-flexion, radial-ulnar devia­
tion and dart throw movements. The
involvement of the FCR is seen in
most of the actions and even though
its presence is expendable, any
change in the normal composition
of the tendon and muscle proportion
would lead to changed performance
of actions at the wrist joint.
Conclusion
The knowledge of such cases would
be of precise importance to physi­
otherapists dealing with rehabilita­
tion cases where the incompetence
of the FCR could be mistaken for
neuronal issues, owing the incompe­
tence to the decreased muscle fibres
in it. Even in reconstructive surger­
ies and oppo­
nensplasty, variations
as the one presented here should be
considered in order to avoid the post
surgical recov­ery delay and regain­
ing essential expec­ted performance
at the wrist joint.
References
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11. Levy HJ, Mashoof AA, Morgan D.
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12. Sabapathy SR, Gowda DK, Ranade AB,
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13. Wallis KL, Hoon Tay P. Re: S. Umarji
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14. Werner FW, Short WH, Palmer AK,
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Licensee OA Publishing London 2013. Creative Commons Attribution License (CC-BY)
For citation purposes: Reghunathan D, Satheesha Nayak B, Surendran S, Kumar N, Rao Sirasanagandla S. Tendinous flexor carpi
radialis: a case report. OA Case Reports 2013 Sep 10;2(10):96.
Competing interests: none declared. Conflict of interests: none declared.
All authors contributed to the conception, design, and preparation of the manuscript, as well as read and approved the final manuscript.
All authors abide by the Association for Medical Ethics (AME) ethical rules of disclosure.
Case Report