Okay. So you have three major plexus in the
body. You have the cervical plexus in the
head and neck, you have the brachial plexus
pretty much for the upper limb, and then you
have the lumbosacral plexus, also called the
lumbar plexus on its own and the sacral plexus.
So these three main plexus cover pretty much
all of the function to the head and neck,
upper limb and the lower limb. Now, what’s
the purpose of plexus? What does plexus mean?
For example, brachial plexus. Why is it called
Collection of meeting of the nerves. Fine,
collection of nerves. So for example,
why do the nerves are to be arranged in plexus?
Why can’t they be just nerve roots?
Because of the nerve that’s joined to form
Yup, that’s right. Anything more? Why do
you needed it to have a, so for example
Less coordination, complex movements
Complex movements. And one more thing. Jay-P?
Is it so that if one root is injured
That’s right. So, take your median
nerve, for example, in the arm, or the radial
nerve. Just one nerve root is injured, say
C6 or C7 is affected, the other roots will
compensate. That’s the main purpose of plexus.
That’s why you have lots of nerve roots
maybe, supplying your intercostal nerves.
So for example, the T4, T5, T6 nerve roots coming
from the spinal cord just supply the intercostals.
They are not arranged in plexus. So even if
one is paralyzed, it’s still okay because
the others will compensate.
For example, when you put a chest drain
in and you damage one of the nerve roots,
that’s not going to be a disaster because
the other intercostal nerves will compensate
for respiration. But on the other hand, imagine
in your upper limb, let’s assume you have
one nerve supplying the whole of the biceps,
and if your one nerve is injured, biceps is
lost. But that doesn’t happen because the
nerves are arranged in plexus. The biceps
is supplied by three nerve roots. So even if
one is affected, the other two will compensate.
So, that’s the purpose of the plexus.
So, let’s start with the brachial