Let’s start from the beginning. The first
one is the lateral pectoral nerve. What does
a lateral pectoral nerve supply?
Pectoralis major, and what about the medial
Pectoralis minor. Pectoralis minor, okay.
The pectoralis major,
since it’s a big muscle, it can be supplied
by both, predominantly from the lateral pectoral
nerve. But the medial pectoralis minor is
supplied by the medial pectoral nerve.
So that is your first nerve taken of pectoral.
Next, the median nerve, who wants to tell
me about median nerve? Tell me about median
nerve. Where does it come from? What does
it supply? So if you go back there, it comes
from the --
C5, C6, C7, well, it comes from all of them.
Exactly, yes, yeah, because it’s coming
from the lateral cord, as well as the medial
cord. So it’s from C5, C6, C7, C8, T1.
You have the axillary artery here. That’s where
it is. Then you have the lateral cord coming
from there. And the medial cord coming from
here, and they’re to join to form the median
nerve. What does median nerve supply in
the arm? Here.
Nothing. Nothing. Very good. It doesn’t
Then it comes to the forearm. What does it
supply in the forearm? Go on. Tell me.
Does it supply all the muscles in the forearm
No. Okay. What doesn’t it supply? What does
it not supply?
The ulnar flexor of the --
Flexor carpi ulnaris, and? And the ulnar
arch of the -- Very good.
So ulnar half of the flexor digitorum profundus.
These two are supplied by the ulnar nerve.
Everything else that’s in the forearm is
supplied by the median nerve. So, what are
the muscles in the forearm at this level in
the flexor compartment?
Yes. We’ve got the profundus and superficialis
and we’ve got palmaris longus, flexor carpi
radialis, flexor carpi ulnaris, flexor -- we’ve
got pronator quadratus.
Fine, flexor digitorum superficialis. Okay,
fine. I’ll go through those in detail.
That’s fine. Does it supply anything else,
the median nerve?
Yes. Hand, so it comes to the hand.
that when it comes to the hand. So, what nerve
supplies this part of the compartment of the
Musculocutaneous. So, one thing you need to
remember for the exam, everything in the flexor
compartment of the arm, this part, his nice
biceps, what are the muscles here? What are
the muscles in the flexor compartment
of the arm?
Coracobrachialis. Okay. So that is your
BBC. BBC is biceps, brachialis, and coracobrachialis.
They are the three muscles in
the flexor compartment of the arm. They may
ask you the origin of these are quite important,
what’s the origin of biceps? You have a
long head and the short head.
Supraglenoid tubercle. Okay. The long head
comes from the supraglenoid
tubercle and the short head comes from the --
Coracoid process. Okay. So that is their origin.
Where does it insert?
Radial -- Radial tuberosity.
from the coracoid process, and where does
it insert? Into the shaft of the humerus.
Brachialis arises from the distal part of the
shaft of the humerus. And where does it insert?
Because the brachialis forms the floor
of the cubital fossa. So, the brachialis is
the most distal muscle here. It inserts into
the radius and the ulnar lower down here.
So that is your BBC supplied by the musculocutaneous
nerve. What’s the root value of musculocutaneous?
C5, C6, C7, because if you work it out, if
you trace your lateral cord back, it’s from
C5, C6, C7. So, three muscles supply the
musculocutaneous, that is three letters, and
three nerve roots, C5, C6, C7. So, that’s
all you need to remember about the anterior
compartment of the arm; musculocutaneous,
three muscles, three nerve roots coming from
the lateral cord. Right. So we have
covered pectoral nerve,
lateral root of median nerve and the medial
root of median nerve, musculocutaneous nerve.
Then you have the medial cutaneous nerve of
the arm, which is here. Next is the medial
cutaneous nerve of the forearm. So they are
both our cutaneous components. And finally,
the ulnar nerve. The ulnar nerve is extremely
important. They will ask you a few things about ulnar
nerve. One of them is which cord. So it’s
coming from the medial cord, root values C8,
T1. Just trace it back. I’m just tracing
back your ulnar nerve.
Okay. So, C8, T1. It is lying medial to the
axillary artery. It’s medial here, comes
all the way down. It’s quite superficial
but it does not supply any of the muscles.
Goes behind the medial epicondyle and it
lays between two muscles here, which two muscles
are they? It lays between the two heads of
the flexor carpi ulnaris. So you have the
flexor carpi ulnaris. It lies between the
two heads, comes all the way down, and it
supplies the flexor carpi ulnaris, and the
ulnar half of flexor digitorum profundus to
these fingers. It comes through the carpal
tunnel. Does it go under the tunnel or --
It goes over. Yeah. It goes over the carpal
tunnel but through
the Guyon’s canal. So it’s very close
to the pisiform bone. Then it comes to the
palm of the hand, and then it supplies most
of the small muscles in the hand, with an exception
which we’ll come to when we discuss the
hand. So that’s mainly your median nerve.
So if you think about it now, you’ve covered
all of the anterior aspect of the arm, the
flexor aspect of the forearm because it’s
separated by the median or the ulnar, nothing
to do with the radial, nothing to do with