Three Medial Plexus of the Body

00:00 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.

00:19 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 brachial plexus? 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 nerves.

00:59 Yup, that’s right. Anything more? Why do you needed it to have a, so for example Less coordination, complex movements I suppose.

01:09 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.

01:50 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.

02:25 So, that’s the purpose of the plexus. So, let’s start with the brachial