Alright guys! In this video we're going to take a look at the arm. So we're gonna
look a lot of the muscles of the arm. Let's go ahead and dive right in. So if
we start right here, we're going to have this muscle right here, this is called
the pectoralis major, this is the pectoralis major right here. And again
we're going to keep saying the function so we can get that drilled into you guys
head. The pectoralis major, it flexes the whole arm at the shoulder joint and
adducts at the shoulder joint and it also does medial rotation at the
shoulder joint. Ok that's the pectoralis major. Right here, this big
superficial muscle right here, this is called the deltoid and there's three
heads, anterior, middle, and posterior head of the deltoid. Now the deltoid muscle in
general it does abduction at the shoulder joint, but obviously you have
three heads. So the anterior head could technically do flexion at the shoulder
joint. The lateral head could do abduction and the rear head of the
deltoid could do extension at the shoulder joint. That's something that you
could technically say but in general we usually just say deltoid muscle is
abduction at the shoulder joint. Okay now, what I'm going to do here is I'm going
to turn it over alright. So now we're going to take a look here, this is a deep
muscle you can see this cut just cut chunk of muscle, this is the trapezius
muscle, the superior trapezius. But underneath this thick trapezius muscle,
we have the supraspinatus, it sits in the supraspinous fossa, and it actually
inserts with the supraspinatus tendon and helps to be able to do abduction at
the shoulder. So it does abduction at the shoulder, so again supraspinatus muscle
right here, does abduction at the shoulder joint alright. So if I turn a
little bit here, again guys what I'm going to do is I'm going to take the
deltoid muscle off, so we can see this big superficial muscle. I'm going to take
that off here, so we can see some of these deeper muscles. Again so, if you
look here, I got this big, big chunk of muscle all right here. All this big chunk
of muscle, this is all the infraspinatus and the infraspinatus again, it
laterally rotates. Okay so it helps to be able to externally
rotate or pull the arm back or the humerus back right? That's what it's design is
to be able to do lateral rotation or external rotation. This muscle right here
that we can see this is actually going to be the teres minor. So this is the
teres minor and the teres minor does the same thing as the infraspinatus, it does
lateral rotation or external rotation of the shoulder. That means that the
infraspinatus and the teres minor are synergist to each other for that action.
And if you look her,e we got another big chunk of muscle right here this is
called the teres major and again the teres major does extension at the
shoulder joint, it does medial rotation and it also does extension at the
shoulder joint. So if you think about it again, he does medial rotation the teres
minor and infraspinatus does lateral rotation. So these two are
antagonist to one another for that action. Ok so again infraspinatus,
teres minor, teres major. Now we're going to do is, we're going to flip this guy
over so we can take a look at two more muscles. Here are actually three more
muscles alright guys. Now we're on the anterior side of scapula, so if you look
here we have this muscle right here sitting in the subscapular fossa, this is
called the subscapularis and the subscapularis does medial rotation. So it
helps to do internal rotation, pull the arm basically forward right at that
shoulder joint right. So that's again, that is the subscapularis. You can see a
tiny chunk here of the latissimus dorsi, because it's going to go insert onto the
humerus. Here you can see the little chunk good latissimus dorsi right there
and then you can see the chunk here of the teres major too. So you got
subscapularis and then you got latissimus dorsi and again
latissimus dorsi does extension at the shoulder joint, he does medial rotation
at the shoulder doing and he does adduction at the shoulder joint. So he's
a synergist for all those actions with the teres major all right. And he'd also
be a synergist to the subscapularis because these two both media
rotate. Alright another muscle that attaches up here at the coracoid process,
this is actually gonna be called the coracobrachialis. So here you got the
coracobrachialis muscle right there. So the coracobrachialis runs kind of all
the way down here and what it helps to do, is helps to be able to flex the whole
arm at the shoulder joint and it does adduction at the shoulder joint ok. So,
the coracobrachialis again does flexion at the shoulder joint and it does
adduction at the shoulder joint. So with that taking into consideration, the
coracobrachialis could be a synergist to latissimus dorsi and it could be a
synergist to the teres major because all three of these muscles do specifically
adduction okay. And again you can see a chunk of the pectoralis major. Now we're
going to do is, we're going to go over here. We're going to take a look at the
biceps muscles. Alright so let's take a look here at the biceps muscle. So if you
can see here, we have a good chunk of the biceps brachii muscle. It's actually two
heads, there's a short head and then there's a long head. I'm going to show
you the long head in a better view, but here we have the short head. And the
short head actually comes up here and attaches to the coracoid process up
there. So that's one of the attachment sites of it. Alright and then if you
look, so that's actually where the origin would be. And so that's going to be the
short head of the biceps, right there is the long head of the biceps, and it
attaches up there, that's called the super glenoid tubercle. But we're just
going to categorize them as just one big muscle, the biceps brachii.
And in general, this whole muscle as a group works together to do flexion at
the elbow, flexion of the whole forearm and then it also supination of the
palms, where it helps to be able to hold, if you think about upholding a bowl soup and
pronation is dumping a bowl of soup. Alright, so that's what it helps to be
able to do is again, flexion of the forearm, flexion at the elbow and it
does supination of the palm. And as you can see here, we can still see the
coracobrachialis right there. And again flexion at the shoulder joint for this
guy and adduction at the shoulder joint for him. So now we're going to do is,
we're going to flip it over, till we can see the a better view of the brachialis
and the long head of the biceps brachii.
Alright, so if we look here we can see this right here. This one on the outside here,
this is the long head of the biceps and again, we already know we already said
what it does. We're going to treat them as a group of the biceps brachii. It's a
flexion of the forearm and supination of the palm, ok. And if we look here, this
is the brachialis muscle. Shis is the brachialis and the brachialis muscle
helps to be able to do flexion of the forearm, flexion at the elbow. So if you
think about it the brachialis muscle is a synergist to the biceps brachii for
flexion of the former flexion at the elbow. Ok. So that covers these bicep
muscles right there. Now what we're going to do is, we're going to flip it over to
the posterior part of the arm, so we can see the tricep muscle. Alright so, if we
look here we have three heads of the tricep. This one right here is the
lateral head of the triceps. So this one right here is a lateral head of the
triceps, this one right here is the long head of the triceps, and then this one
right here is the short head or the medial head of the triceps. All of these
make up what's called the triceps brachii right. So the triceps brachii
helped to be able to do what's called extension at the elbow or extension of
the forearm. There's another muscle that's a tiny little one down here it's
called the anconeus. And the anconeus also does extension at the elbow or
extension of the forearm. So we think about the anconeus and the triceps brachii
muscles are both, all of them are antagonist to the biceps brachii and the
brachialis for these guys doing extension at the forearm and the bicep
muscles doing flexion at the forum. So these two guys are going to be
antagonist to one another, whereas the triceps brachii and the anconeus would
be synergist to one another. Alright guys, so what we're going to do is we're going
to look at the muscles of the forearm, the extensor side. So if you see here, we have
this muscle right here. First this is called the brachioradialis. That's the
brachioradialis. And the brachioradialis does flexion of the forearm or flexion at the elbow joint.
Im going to turn a little bit. Extensor carpi radialis longus right there and as you
can tell by the name it extends carpi, extends the wrist. So extensor carpi
radialis longus, it extends the wrist. Lo and behold, here is extensor carpi
radialis brevis, it also extends the wrist. So longest just means it's a lot
longer, brevis means it's shorter. Turn it over here, this is the extensor digitorum.
Says the name extends the digits. This is extensor digiti minimi, ok. Extends the
digits. This right here is going to be the extensor carpi ulnaris. Alright, so
extend the wrist. So that covers all the muscles on the extensor side. What we're
going to do is, we're going to flip it over and we're going to cover the flexor
side. Alright guys, if you look right here we have the flexor side. So this is going to
be called the pronator teres and he pronates the palm. So again remember if
you hold the bowl soup, it's supination. If you dump the bowl soup, it's pronation.
So he does pronation of the palms, that's the pronator teres right here. Next to
him, is going to be the flexor carpi radialis, so it flexes the wrist. Next to
him, is the palmaris longus and the palmaris longus also flexes the wrist.
And we have one more over here, this is called the flexor carpi ulnaris and this
one also flexes the wrist. Now we have another set of muscles that I want to
cover that are deeper here. I'm going to take this off here. Alright guys, so now
we're going to take a look here at the deeper part. So if you look here, this is
the flexor digitorum superficialis, all this muscle right here ok. And to get to
him, we had to take off all this layers that we just showed you right here. So we
had to take off the pronator teres, we had to take off the flexor carpi
radialis and we had to take off the palmaris longus. So if I come take that
off again, you can see there the flexor digitorum superficialis. And the flexor
digitorum superficialis flexes the digits and then eventually the wrist ok.
So if you think about it, he is a synergist to the flexor carpi radialis,
he's also a synergist to the flexor carpi ulnaris for flexion at the wrist.
Okay, now i'm going to do is, I'm going to take the flexor digitorum superficialis
off, so that we can see the deeper layers. This right here guys, the flexor
pollicis longus right there. So flexor pollicis longus, then if you look over
here, this is going to be the flexor digitorum profundus right there. So again
we got the flexor pollicis longus, which flexes the pollex. And then over here we
got the flexor digitorum profundus which flexes the digits. Okay, so these two
muscles right here are going to be deep to that muscle that we just talked about,
being the flexor digitorum superficialis. Now, I'm going to turn it over here more
and you can see this really, really deep muscle right here. This is called the
supinator and the supinator like we said it supa nates the palms, that helps to
hold the bowl of soup ok. That's the supinator muscle right there and if you
think about it the supinator is a synergist to the biceps brachii right,
for supination at the palm. And it's going to be an antagonist to the
pronator teres, which pronates the palm. There is another pronator muscle that
you can't see on this, it's called the pronator quadratus it's going to be
closer down here to the wrist region, but that's another muscle. So you could also
say an antagonist to the supinator, is not only the pronator teres but the
pronator quadratus ok. So now, we're going to take a look here at the thumb. These
are the thenar muscles, thenar eminences. If you look here, we got this tiny little
muscle right here, that's going to be the opponens pollicis right there. This
muscle right here is going to be the abductor pollicis brevis and this one
right here is going to be the flexor pollicis brevis. Right there flexor
pollicis brevis and then 30 right there there's going to be the adductor pollicis
brevis. And this covers the thenar muscles right there. Alright guys so now
we're going to look over here at the hypothenar muscles. So over here we have
this one right here, this is the opponens digiti minimi right there. And then this
one right here is going to be the abductor digiti minimi. And if I flip it
inwards in here, this last one right here is going to be the flexor digiti minimi.
Alright guys, so that gives us basically an overall look at the entire arm and
all the muscles that actually contains.