Now, let's talk about the blood supply.
We started off with the right subclavian artery
which change names when it reached the axilla
to become the axillary artery
then after it gave those last branches,
the anterior and posterior circumflex arteries,
it changed names again
to become the brachial artery.
And the brachial artery is going to give off branches
along the way including deep branches
to reach stuff like the triceps
so we have deep brachial artery.
And then, it's going to branch again distally
into appropriately names radial and ulnar arteries
on their respective sides of the forearm
and a very useful feature is that they will combine again
at something called the palmar arch.
When two arteries come together and connect again,
we call that an anastomosis and it provides
what we call collateral supply which is very important.
For example, let's say for some reason the radial artery
was to be blocked by some sort of obstruction.
Well, that means everything distal to it that's supplied
in the hand would eventually not have oxygen and die.
Fortunately, there's what we call collateral supply from the palmar arch
which also is receiving blood from the ulnar artery
so these situations are very important clinically
and we're very lucky to have them.
The nerves of the upper limb all come
from the brachial plexus
and those initial spinal nerves
that do a lot of combining and recombining
to eventually form named nerves
that innervate the upper limb.
The first one we saw in the arm was the musculocutaneous nerve
doing the anterior compartment of the arm's muscles
but also providing cutaneous innervation of the skin.
We had that radial nerve
doing the posterior compartment for us.
We've mentioned the ulnar nerve and the median nerve
for all the things they do in the hand.