The brachial plexus is a network of nerves that conducts signals from the spine to the shoulder, arm, and hand. Brachial plexus injuries are caused by damage to those nerves. Symptoms may include a limp or paralyzed arm; lack of muscle control in the arm, hand, or wrist; and a lack of feeling or sensation in the arm or hand. Brachial plexus injuries can occur as a result of shoulder trauma, tumors, or inflammation.
There is a rare syndrome called Parsonage-Turner Syndrome, or brachial plexitis, which causes inflammation of the brachial plexus without any obvious shoulder injury. This syndrome can begin with severe shoulder or arm pain followed by weakness and numbness. In infants, brachial plexus injuries may happen during birth if the baby’s shoulder is stretched during passage in the birth canal.
What happens when the brachial plexus is injured?
The
network
of
nerves
is
fragile
and
can
be
damaged
by
pressure,
stretching,
or
cutting.
Stretching
can
occur
when
the
head
and
neck
are
forced
away
from
the
shoulder,
such
as
might
happen
in a
fall
off a
motorcycle.
If
severe
enough,
the
nerves
can
actually
avulse,
or
tear
out
of,
their
roots
in
the
neck.
Pressure
could
occur
from
crushing
of
the
brachial
plexus
between
the
collarbone
and
first
rib,
or
swelling
in
this
area
from
injured
muscles
or
other
structures.
Injury
to a
nerve
can
stop
signals
to
and
from
the
brain,
preventing
the
muscles
of
the
arm
and
hand
from
working
properly,
and
causing
loss
of
feeling
in
the
area
supplied
by
the
injured
nerve.
When
a
nerve
is
cut,
both
the
nerve
and
the
insulation
are
broken.
Pressure
or
stretching
injuries
can
cause
the
fibers
that
carry
the
information
to
break
and
stop
the
nerve
from
working,
without
damaging
the
cover.
When
nerve
fibers
are
cut,
the
end
of
the
fiber
farthest
from
the
brain
dies,
while
the
insulation
stays
healthy.
The
end
that
is
closest
to
the
brain
does
not
die,
and
after
some
time
may
begin
to
heal.
If
the
insulation
was
not
cut,
new
fibers
may
grow
down
the
empty
cover
of
the
tissue
until
reaching
a
muscle
or
sensory
receptor.
Some
brachial
plexus
injuries
are
minor
and
will
completely
recover
in
several
weeks.
Other
injuries
are
severe
enough
that
some
permanent
disability
involving
the
arm
can
be
expected.
Treatment
Many
brachial
plexus
injuries
can
recover
with time
and
therapy.
The time
for
recovery
can be
weeks or
months.
When an
injury is
unlikely
to
improve,
several
surgical
techniques
can be
used to
improve
the
recovery.
To help
decide
which
injuries
are likely
to
recover,
your
physician
will rely
upon
multiple
examinations
of the arm
and hand
to check
the
strength
of muscles
and
sensation.
Additional
testing,
such as an
MRI scan,
or CT
scan/myelography,
may be
used to
visually
evaluate
the
brachial
plexus.
A Nerve Conduction Study/Electromyogram (NCS/EMG), a test that measures the electrical activity transmitted by nerves and muscles, may also be performed. In some cases, repair of the nerves or transfer of undamaged nerves from other areas of the body can be performed. In other cases, transfer of functioning muscles (tendon transfer) to take over areas of lost function can be performed.