Elbow muscles (anatomy)

Summary

This educational video delves into upper limb anatomy, focusing on the muscles involved in elbow flexion and extension. It covers key terms, bony landmarks, and the roles of muscles like biceps brachii, brachialis, and triceps brachii in forearm movements, emphasizing their attachments and functions.

Takeaways

• 📚 The speaker acknowledges a gap in their knowledge of upper limb anatomy, specifically around elbow flexion and extension.
• 🏃‍♂️ The speaker is preparing for an ultra-marathon, which adds a layer of nervous excitement to the discussion.
• 💪 The focus of the discussion is on the major muscles involved in flexion and extension of the forearm at the elbow joint.
• 🔍 The speaker introduces terminology for different parts of the upper limb, including the glenohumeral joint, brachium, antebrachium, and upper limb.
• 🦴 The elbow joint is described as a hinge joint, but with additional capabilities due to the movement of the radius and ulna bones.
• 🤲 The importance of understanding muscle attachments is emphasized, as it helps determine the functions of muscles in relation to joint movements.
• 🏋️‍♂️ Biceps brachii is highlighted as a key muscle for elbow flexion, with its two heads attaching at different points on the scapula and inserting at the radial tuberosity.
• 🤸‍♂️ Brachialis is identified as a deep muscle that plays a significant role in elbow flexion, attaching to the distal half of the humerus and inserting into the ulnar tuberosity.
• 🤞 Brachioradialis is mentioned as a muscle involved in elbow flexion, particularly when the forearm is partially pronated.
• 💪 Triceps brachii is described as the primary muscle for extending the forearm at the elbow, with three heads attaching to different parts of the humerus and inserting into the ulna.
• 🤔 The speaker also discusses the role of the anconeus muscle in stabilizing the elbow joint during pronation and supination, and its attachment to the joint capsule.

Q & A

What is the main focus of the video script?

The main focus of the video script is to discuss the anatomy of the upper limb, specifically the muscles involved in flexion and extension of the forearm at the elbow joint.

What are the terms used to describe different parts of the arm?

The terms used include 'humerus' for the upper arm bone, 'radius' and 'ulna' for the forearm bones, 'glenohumeral joint' for the shoulder joint, 'antebrachium' for the forearm, and 'brachialis' for a muscle in the arm.

What is the function of the biceps brachii muscle?

The biceps brachii muscle is primarily responsible for flexion of the forearm at the elbow joint. It also assists in supination of the forearm when the elbow is flexed at around 90 degrees.

How does the biceps brachii muscle attach to the bones?

The biceps brachii has two heads: the long head attaches to the supraglenoid tubercle of the scapula and the short head attaches to the coracoid process of the scapula. Both heads converge and insert into the radial tuberosity on the radius bone.

What is the role of the brachialis muscle in elbow flexion?

The brachialis muscle is a powerful flexor of the forearm at the elbow joint. It runs from the distal half to two-thirds of the humerus to the ulnar tuberosity and the coronoid process of the ulna.

What is the significance of the radial and ulnar tuberosities in muscle attachment?

The radial and ulnar tuberosities are bony prominences where muscles attach. The radial tuberosity is where the biceps brachii attaches, and the ulnar tuberosity is where the brachialis attaches. These tuberosities provide leverage for the muscles to perform their functions.

What muscle is involved in both elbow flexion and extension, and what is its role?

The brachioradialis muscle is involved in elbow flexion, particularly when the forearm is partially pronated. It runs from the distal part of the humerus to the distal radius.

What are the three heads of the triceps brachii muscle and their origins?

The triceps brachii has three heads: the long head, which originates from the infraglenoid tubercle of the scapula; the lateral head, which originates from the proximal third of the humerus; and the medial head, which has a large attachment site across the posterior surface of the humerus.

What is the function of the anconeus muscle?

The anconeus muscle assists in extension of the forearm at the elbow joint and helps stabilize the elbow joint during pronation and supination. It also puts tension on the joint capsule, preventing impingement.

Why is it important to understand the attachment points of muscles?

Understanding the attachment points of muscles is crucial as it helps determine the actions and functions of the muscles. It also provides insights into how muscles contribute to movements and potential issues like muscle strains or joint instability.

What is the role of the pronator teres muscle in forearm movement?

The pronator teres muscle is primarily responsible for pronation of the forearm. It is also described as having a role in elbow flexion due to the power it exerts during the movement.

Outlines

00:00

💪 Upper Limb Anatomy and Elbow Joint

The speaker acknowledges a gap in their upper limb anatomy knowledge, specifically around elbow flexion and extension. They express nervousness due to an upcoming ultra-marathon. The focus shifts to the major muscles involved in forearm flexion and extension at the elbow. The speaker introduces the terminology for different parts of the arm, such as the glenohumeral joint, brachium, antebrachia, and upper limb. They also discuss the elbow joint's structure, highlighting the humerus, radius, and ulna, and their roles in pronation and supination. The importance of understanding muscle attachment points is emphasized for determining muscle functions.

05:02

🏋️‍♂️ Biceps Brachii and Its Functions

The speaker delves into the anatomy of the biceps brachii, a muscle with two heads known for its role in flexing the forearm at the elbow. They describe the biceps' origins from the scapula's coracoid process and supraglenoid tubercle, and its insertion at the radial tuberosity. The biceps' dual role in flexion and supination is discussed, with emphasis on its effectiveness when the forearm is supinated. The speaker also explains the biceps' aponeurosis, which provides protection to the brachial artery and median nerve in the cubital fossa.

10:04

🤔 Biceps and Its Role in Pronation and Supination

Continuing the discussion on biceps, the speaker explores how the muscle's attachment to the radius affects its function in pronation and supination. They illustrate that biceps is less effective in flexing the forearm when the forearm is pronated, but becomes a powerful supinator when the forearm is supinated. The speaker also connects this to practical activities like screwing and climbing, highlighting biceps' utility in underhand pull-ups and its lesser role in overhand pull-ups.

15:05

💪 Brachialis and Brachioradialis: Deep Flexors of the Elbow

The speaker introduces brachialis and brachioradialis, two muscles crucial for elbow flexion. Brachialis is described as attaching to the distal half of the humerus and inserting into the ulnar tuberosity, making it a powerful flexor. Brachioradialis, originating from the distal humerus, is noted for its role in flexion when the forearm is partially pronated. The speaker also mentions the innervation of these muscles by the musculocutaneous nerve and the radial nerve, respectively.

20:08

🤲 Muscles Involved in Wrist Flexion and Extension

The speaker discusses the muscles that cross the elbow joint and are primarily involved in wrist flexion and extension. They mention flexor carpi and extensor carpi muscles, emphasizing their role in stabilizing the wrist. The speaker also touches on the pronator teres and its potential role in elbow flexion. The focus then shifts to the posterior arm muscles, highlighting triceps brachii as the main extensor of the forearm at the elbow, with its three heads (long, lateral, and medial) and their attachments.

25:13

💪 Triceps Brachii and Anconeus: Extending the Forearm

The speaker concludes with a detailed look at triceps brachii, the primary muscle for extending the forearm at the elbow. They describe the muscle's three heads and their origins, and how they converge to insert into the olecranon of the ulna. The role of triceps in everyday activities like pushing up from chairs is highlighted. The anconeus muscle is also introduced as a stabilizer of the elbow joint during pronation and supination, with its attachment to the lateral epicondyle and the ulna.

👋 Wrapping Up the Discussion on Arm Muscles

In the final paragraph, the speaker briefly mentions that they have covered most aspects of the arm muscles and looks forward to continuing the discussion in the next session. The focus is on the practical application of this knowledge, hinting at the importance of understanding muscle functions in various activities.

Keywords

💡Upper Limb Anatomy

Upper Limb Anatomy refers to the study of the structures and functions of the arm, forearm, and hand. In the video, the speaker discusses this topic in the context of muscles and joints involved in elbow flexion and extension, highlighting the importance of understanding the anatomy for activities like running an ultra-marathon.

💡Elbow Flexion and Extension

Elbow flexion and extension are movements that involve bending and straightening the arm at the elbow joint. The speaker focuses on these movements to explain the role of various muscles in the forearm and upper arm, emphasizing the importance of these muscles in daily activities and sports.

💡Glenohumeral Joint

The glenohumeral joint is the ball-and-socket joint that connects the arm (humerus) to the shoulder blade (scapula). It is mentioned in the script to illustrate the broader context of upper limb anatomy, showing how the movements of the arm are interconnected with the shoulder joint.

💡Humerus

The humerus is the long bone of the upper arm that extends from the shoulder to the elbow. It is a key bone discussed in the video, especially in relation to the attachment points of muscles that facilitate elbow flexion and extension.

💡Radius and Ulna

The radius and ulna are the two bones of the forearm that work together to allow for movement and rotation of the wrist and hand. The speaker discusses these bones in the context of pronation and supination, explaining how they move in relation to each other and the humerus during these movements.

💡Biceps Brachii

Biceps brachii is a muscle with two heads that is well-known for its role in flexing the forearm at the elbow. The speaker explains that this muscle also plays a role in supination when the forearm is in a certain position, highlighting its dual function in both flexion and rotation.

💡Brachialis

Brachialis is a muscle located deep in the arm that is primarily responsible for flexing the forearm at the elbow. The speaker describes it as an 'unsung' muscle, indicating that while it is crucial for elbow flexion, it is often overlooked compared to more visible muscles like the biceps.

💡Triceps Brachii

Triceps brachii is a large muscle on the back of the upper arm that is responsible for extending the forearm at the elbow. The speaker emphasizes its importance in activities that require pushing, such as getting up from a chair, and notes that it is a key muscle for achieving functional strength.

💡Pronation and Supination

Pronation and supination are movements that allow the forearm to rotate, turning the palm downward and upward, respectively. The speaker discusses these movements in relation to the actions of the biceps and how the position of the forearm affects the muscle's ability to flex the elbow.

💡Anterior and Posterior Muscles

Anterior and posterior muscles refer to the muscles located at the front and back of the body, respectively. In the context of the video, the speaker uses these terms to categorize the muscles that cross the elbow joint, explaining their roles in flexion and extension.

💡Epicondyles

The medial and lateral epicondyles are bony prominences on either side of the elbow joint. The speaker mentions these as attachment sites for several muscles that cross the elbow, playing a crucial role in the mechanics of elbow flexion and extension.

Highlights

Introduction to upper limb anatomy, focusing on muscles involved in elbow flexion and extension.

Terminology review: distinction between upper limb, arm, and antebrachium.

Explanation of the elbow joint as a hinge joint with additional movements like pronation and supination.

Importance of the radius and ulna in forearm movements, including their role in pronation and supination.

Identification of bony landmarks such as the radial and ulnar tuberosities and their relevance to muscle attachment.

Discussion on the muscles that cross the elbow joint and their potential roles in flexion, extension, pronation, and supination.

Detailed anatomy of the biceps brachii, including its two heads and their origins on the scapula.

Function of biceps brachii in flexion of the forearm and its interaction with pronation and supination.

Role of the brachialis muscle in elbow flexion and its attachment to the ulnar tuberosity.

Influence of the brachioradialis muscle in elbow flexion, especially when the forearm is partially pronated.

Description of the coracobrachialis muscle and its function in shoulder stability rather than elbow movement.

Overview of the triceps brachii muscle, its three heads, and its primary role in forearm extension.

Importance of the triceps brachii in stabilizing the elbow joint during movements.

Introduction to the anconeus muscle, its attachment to the lateral epicondyle, and its role in elbow extension and joint stabilization.

Discussion on the practical application of this anatomy knowledge in activities like climbing and swimming.

Emphasis on the importance of studying anatomy through practical dissection in addition to theoretical learning.

Summary of the key muscles involved in elbow flexion and extension, and their functional significance.

Transcripts

so one of you guys are possibly more

than one of you guys pointed out to me

that although I've done an awful lot of

upper limb Anatomy I missed out a bit

I've missed out this bit here as easily

have missed out elbow flexion and

extension so I'm a little bit antsy

today because um I'm running an ultra

marathon tomorrow you know kind of

excitement puts you on edge nervousness

all that sort of thing so I'm not

talking about my legs I'm going to talk

about the major muscles of flexion of

the forearm at the elbow and extension

of the forearm at the elbow so him and

him and need three amigos I get a

copyright strike for that the three of

us are gonna teach you a little bit of

upper limb anatomy okay so we need to do

let's go back and do a little bit of

terminology first so if this is the

shoulder region this under here is the

glenohumeral joint and excuse me we've

got you know flexion extension abduction

so abduction adduction of the humerus at

the glenohumeral joint the arm or break

IAM runs from the shoulder region up

here down to the the elbow joint that's

the break IAM because the word breaking

gets used in a number of structures

around here and then this down here from

the elbow to the wrist this is the

antebrachium or the forearm and that

plus the hand in the wrist all of this

stuff gets called the upper limb I like

that I like upper limb up a limb works

for me we don't tend to use arm not you

see because um some people call it the

upper extremity mmm doesn't sit inside

my brain that upper limbs fine up for

extremity mmm kind of like chewing sand

so what I want to do is I want to group

the muscles that are anterior and

posterior and we'll talk about the

muscles and cross the elbow joint we'll

talk about what they do with the elbow

joint and we'll talk about their

attachment points their innovation and a

so

thing and there aren't very many so if

we're gonna talk about the movements of

the elbow joint we're gonna need to look

at the elbow joint itself we have looked

at the humerus the radius and the ulna

in three separate videos called the

humerus the radius nil so we've looked

at these bones in detail we've looked at

the elbow joint essentially the elbow

joint is a is a hinge but there is more

to it than that so it's it's um it's

largely a hinge joint this is the

forearm so the on the thumb side that's

where the radius is and on the little

finger side that's where the ulna bone

is that's these two bones here and we

have these two bones because that allows

us to do a royal wave it's how royal

wave it allows you to pronate so yet to

pronate and supinate right so you can

pronate and supinate your forearm and

what happens when you do that is that

the the the ulna remains in in place the

owner doesn't move the radius moves

about it the mate radius moves around

which means that any bone that's pulling

on the radius has the potential to cause

pronation or supination

this is suppon ated this is pronated

supination pronation so we've got the

hinge so both the the radius and the

ulna will move about the the humerus to

give that hinging movement so really I

mean to look at these bones in details

go watch those other videos but really

what we're interested in is a few bony

bits this is the radius there's the

radial tuberosity on the other side

there's the ulnar tuberosity little

bulge there if you've got a little lump

that's where muscles are attaching and

here all right the bony bit of your

elbow

that's your electron on and that is part

of the ulna and that's a big lumpy bit

again so the muscles can attach to it

right

the humerus is got the other thing on

the humerus I guess it's most

interesting today these these

epicondyles these are the bony bits on

on either side so we have medial and

lateral epicondyles we have a whole

bunch of muscles attaching there so if

we talk about the elbow joint today and

the muscles of the elbow joint any

muscles we should consider there any

muscles that cross the elbow joint as

potentially having a role in flexion of

the forearm at the elbow joint or

extension of the forearm of the elbow

joint and maybe also having a role in

pronation or supination all right

depending upon where they attach so

that's why it's important to learn where

muscles attach because you can work out

what's going on well look at the

posterior layers of muscles here and

then we'll add in the muscles of the

forearm not also cross across this joint

con can't link it all together we'll

make it sense

we'll make it make sense the reason

we're in here again today is because

we've got an exam coming up so the lab

is full of students and that is a good

thing just because you're watching some

bloke on the internet talking about

Anatomy doesn't mean you're studying

Anatomy the way to study Anatomy is to

get in the lab and look at these things

there's more to Anatomy than just

reading books and and being taught it a

big part of studying Anatomy is studying

Anatomy if you're lucky enough to have

these resources right so first muscle

pretty straightforward is biceps isn't a

biceps brachii and you know biceps

brachii because everybody knows biceps

you know why it's called biceps because

SEPs comes from the word kaput cept

means head by two so this is a muscle

with two heads and what we're talking

about here is we're talking about we

have the origin up here and then we have

the insertion down here talking about

the two heads of the muscle coming from

two separate origins right first of all

they're figures and bony bits this all

this here that's the scapula all right

scapula around here here's the clavicle

we're not interested in the clavicle

stay we're interested in the scapula

scapula clavicle I have to be careful I

get those two words backwards like like

I get a red and blue back

in stuff like that you know I mean I

some people get left and right the wrong

way around its scapula and clavicle for

me scapula club definitely scapula right

so this is the scapula and see this

little this shallow depression here this

is the the glenoid fossa we've talked

about this before this is kind of the

socket of the ball and socket joint of

the glenohumeral joint this here they're

sticky empty bit this is the coracoid

process so we've got the coracoid

process the glenoid fossa now can you

see that's the coracoid process up here

there's a little tiny lump

natella tubercle that's the supra

glenoid tubercle and those are the two

attachment sites for biceps brachii and

the long head has to take the longest

route so the long head actually comes

off this supraglenoid tubercle and then

it runs through this groove here this

intertubercular sulcus because what

these two tubercles here runs through

the intertubercular sulcus is held down

by a ligament and then runs into the

into the young into their right or is

the short head starts off from the

coracoid process and runs across we've

got deltoid here in the waist and

deltoid is yeah of your shoulder isn't

in there so take gal Toit off now look

now you can see biceps brachii and we

can see what it means by the two heads

now here's the long head so there it is

disappearing into that intertubercular

sulcus there's that ligament that's

tying it down she was going through the

groove over the top and over the top of

the glenoid fossa into that supraglenoid

tubercle you know this is a short head

which isn't traveling as far as going in

a straight line it's not looping over

the top where the bone head does long

head looks a bit short here because we

got the arm sticking out if you had it

down by the side a bit further anyway so

the short head is coming off that

coracoid process of the scapula there in

book

see those two heads coming together here

so there's that that muscle bulk that

we're very used to seeing in the the

theoria arm and look what's it doing

okay so it carries on through and it

becomes a single tendon here well

actually that's will meet the sanctum

you'll see a bit more just a single 10

if I take my take that off what can we

see yeah I we go now you see that single

tendon look so this is the thumb up here

so this is your radial pulse the radial

artery so the radial bones on this side

on the bones on that side so that biceps

is inserting into the radial tuberosity

that little lumpy bit in the very

proximal part of the radial bone in fact

when we're the setting we see a bit more

than this and you can probably feel it

in yourself you can feel the tender nail

it's not just a tendon it's very much a

flat sheet of connective tissue coming

across here right so we have the tendon

inserting into the radial tuberosity we

also have like a fanning out we have a

bicep petal aponeurosis and aponeurosis

is like a a flattened sheet of tendon

and that bicep to aponeurosis expands

out into the forearm and it attaches

into the the antebrachial fascia the

deep fashion of the forearm which means

that see this is quite painful a

difficult area to dissect because you

don't just dissect out of this single

tendon you get there's a pony rope this

comes out if I'm gonna take away the

fash you have to decide where do i where

do i you know where do I cut it out what

do we leave us or think anyway in life

that bicipital pony ropes this is quite

useful because in here you've got your

median nerve ulnar nerve brachial artery

and that sort of thing right so this is

the cubital fossa then coming in for

cubital fossa you have your brachial

artery which is going to split into two

and you have your median nerve so that

bicipital aponeurosis there that is is

covering the brachial artery and the

median nerve or giving them a bit of

protection here which is a good thing

right

so that's how biceps attach it have you

know it's what it's done it's not

attaching to the humerus

anywhere right it's attached to the

scapula

at two points up here and is attached to

the radius

down here completely mr. the humorous

hasn't bothered attaching so humorous at

all did you know that its top fact now

the fact that it attaches to the radius

means we have to think about pronation

and supination so if if biceps is well

you know it's got a couple of actions

hasn't it because it's crossed in the

shoulder joint it can help with holding

the humerus into the glenohumeral joint

right which is a good thing so helps

prevent dislocation and stuff but if

we're considering the elbow today then

the main job of biceps is flexion of the

forearm at the elbow alright it's very

good at that but because it attaches to

the radial tuberosity because it goes in

here and attaches the Ray which made

with tuberosity it means that when when

you are when your forearms are supine it

finds that job easy it's very good at

that job it's great you're going from

extension to 90 degrees and Beyond very

happy because it's attaching here right

very straight forward but what happens

to the radial tuberosity

if you pronate oh that's awkward

now if your biceps you oh you know all

the way around there that's a pain in it

so if your pronated and biceps contract

what's going to happen well it's gonna

want to pull the radius around this way

isn't it do you see so if you're like

this and you use bicep feel like you can

see this because if you if we flex the

forearm there but make sense really

isn't that strong it's not really doing

much when I'm flexing the forearm at the

elbow joint when I'm pronated right it's

kind of a bit squidgy but when I flex

the forearm at the elbow against

resistance when suppon ated I need

someone to push against ah now it's it's

gone solid now it's doing a good job now

it's more useful right so what that

means is that

when the elbow joint is about 90 degrees

biceps actually becomes a very good very

powerful sup inator of the forearm so

when you're screwing a screw in right

you're doing it with a belt don't do it

like that D that's that's just too hard

if you if you're screwing a screw into

some wood or wherever and you need

really good supination you do it with a

bent elbow and the reason you do with

the bent elbow is because you get to get

used biceps to help you do that alright

so I'm doing that other biceps is it's

busyness see that's the importance of

biceps inserting into the radial

tuberosity and the radius moving about

the ulna in pronation and supination

what this also means that if you're a

climber like me or a swimmer it means

that so doing an an overhand pull up

alright so with a pull-up you're mostly

using latissimus dorsi that's the muscle

of power but also you wanna you gotta

flex your elbows right it means that

when you're doing an overhand pull up

biceps is not actually a lot of use if

you're doing an underhand pull-up you

get to work biceps a lot more allright

biceps is great when you're doing an

underhand pull up at flexing the elbow

okay so there must be other muscles that

we use that are also very powerful when

we're doing say an overhand pull up what

we're doing front crawl and we want to

flex the elbow with some power all there

is and if we take off biceps we're going

to see a couple of things the muscle

deep - biceps is brachialis well that's

very sensible because of course this is

the the brachial bit in it the brachial

and brachialis runs from below you can

see the brachialis is is the muscle

that's attaching to much of the humerus

here so if the humerus is going from

here to here it's kind of like the

distal half distal two-thirds of the

humerus anteriorly a rat by brachialis

and brachialis is then crossing the

elbow joint and it's actually going to

insert into the the ulnar tuberosity and

a little bit of bone

along to the tuberosity which gets

called the kind of the coronoid process

coronoid coracoid sorry I'm didn't name

all these things anyway if you want to

look at the detail bits of the own

they're going to see that video but so

breaking on ice goes across the elbow

here which means that brachialis is a

very powerful and effective flexor of

the forearm of the elbow so break down

is actually doing a lot of work but it's

a very you know it's kind of an unsung

muscle so that lies deep - biceps

brachii look we can see the nerve

innervates these two muscles here this

is the musculocutaneous nerve a branch

of the brachial plexus must and it's the

muscular job that it does is it runs

into this anterior in anterior arm and

innovates brachialis and boy shows

breaking I break Yaris does in a by I

think in most people it also gets a

little bit of innovation from the radial

nerve so watch out for that but we tend

to describe brachialis advices brachii

has been innovated by I must go to

cutaneous nerve here right and if we

take off brachialis we just see the

humerus so that's it for the anterior

muscles there and we've got this guy

here was this guy crossing the elbow

joint then right want to show you this

let's this muscle here we've got a bunch

of muscles here but it's the one here

closer to the cubital fossa this one

[Music]

if the Swansea Air Show this weekend it

sound like they're warming up okay

anyway so this is brachioradialis right

so from the name that means it goes from

the brachial to the radial bone

brachioradialis comes from the the

distal part of the humerus here just

proximal to the epicondyle

so that's the break you're

brachioradialis goes from here and then

it runs all the way down to like the

distal radius down here so it's quite a

long muscle and we can see this on

ourselves when you have you so again

going from supine to pronated Supper

needed to pronated when you're partially

like 90 degrees pronated when you then

flex the elbow it's this that pops up

here right so that's brachioradialis so

obviously then break your radiolysis

involved in elbow flexion but it's only

really involved in elbow flexion when

you're partially pronated all right

it's innervated by the radial nerve and

apparently it's some fairly weak at

flexing the elbow but there you go

there is another muscle isn't there so

there's this guy here this is

coracobrachialis so Conoco breaking are

this also seems to be names going to go

from that coracoid process of the

scapula to the humerus the breaking the

breaking part of the armour

coracobrachialis though it's not

crossing the elbow so we're not really

talking about it today again it's

involved in you know holding the

shoulder together

Toriko brachii right now so we do the

akan let's do this side first and we go

to choice if now we can see down here

this week on time to break your radius

we can see there are a lot of other

muscles running from the epicondyles of

the humerus and cross therefore crossing

the elbow joint because the epicondyles

are part of the humerus crossing the

elbow joint and going into the forearm

and we've got all of these flexors here

which are going to the wrist so flexor

carpi this that and the other and so on

and then on the other side we've got

extends to copy this than the other

extensor carpi radialis print that's

actually giving me a bit my extensor

carpi radialis brevis to give me a bit

of at the moment from what climbing

swimming bit of all that as is

stabilizes the wrist anyway extensor

carpi radialis longus

crosses the elbow a bit further against

the other side lyrical anyway we have a

lot of muscles which will run into the

forearm which are primarily involved in

say wrist flexion and extension and

stabilizing the wrist that also crossed

the elbow joint they are not generally

considered to have a role in elbow

flexion or extension pruney Tutera's

here its main job is pronation it pulls

the radius around we've talked about the

forearm muscles elsewhere go and watch

that video if you want more the pronator

teres does get described as also having

a role in elbow flexion because

scissoring the power these muscles exert

it's kind of a dv1 right so it helps

imprint

anyway pronator terrorism so that these

guys right last of all then we need to

go to the posterior braking and think

about these muscles really most of the

work is done by triceps triceps brachii

but there's also another little muscle

called Antonius so if we if we go back

to the skeleton then and we look at the

bony bits first again scapula glenoid

fossa humerus

there's the electron on of the ulna the

triceps muscle has three heads triceps

so twice abs brachii it has a long head

a lateral head and a medial head now the

long head crosses the glenohumeral joint

and it comes from the infra glenoid

tubercle down here and then runs down

the the lateral head it's kind of got

like a fairly thin skinny attachment

site to the humerus but that's coming

from the humerus up here kind of in the

proximal third and we talked about these

the spiral groove and we look to the

humerus which brownish things running so

that the lateral head is kind of high up

there and then the medial head that's

kind of the part on the muscle that does

the bulk of the work that's got a great

big attachment site across the humerus

like the rest of the posterior surface

of the humerus and then all of those

three

it's come together they cross the elbow

joint and they insert into the electron

on so that's what's the elect what the

electron on is four nice big chunky

attachment site for this big muscle also

give because it sticks I would get a

little bit of a leverage advantage and

that's the muscle that's largely

involved in extension of the forearm at

the elbow so this is it's a big muscle

in fact if you want big arms you don't

really want big biceps you come on big

triceps because it's so much of the

muscle but your choice those brachialis

and bicycles train all those things

anyway I don't functional strength

that's what I'm after

but triceps then it's the powerful

extender of the forearm at the elbow

joint very important in you know pushing

yourself up from chairs and get all that

sort of stuff right

it's innervated by the radial nerve from

the brachial plexus that winds is way

around here because it's also crossing

the glenohumeral joint also has a role

in holding the humerus into the

glenohumeral joint stops to dislocating

why it's good to have these strong

muscles because it also holds this kind

of unstable joint in place right it's

not just the rotator cuff it's the other

muscles as well to hold this together

yes there's a video on the rotator cuff

and I think some of the fibers probably

also insert into the break your fascia

because we get a bit of that one made

the second thing it kind of fans out a

little bit it's not just like a tendon

it's kind of a bit of a pony roses in

certainly to the antebrachial fascia

there's also a little bursa between the

tendon and the electron on here to stop

wearing that sort of thing but that's

triceps the last muscle is and Konya say

let's not look at triceps on the arm

Sheree so you can see long head lateral

head medial head so the medial head is

deep if they all come together inserting

the electron there not much to it really

can't really see Antonius and Kony's is

a little muscle it kind of blends with

with triceps so it's often a little bit

difficult to detect error and

distinguish but it runs

the lateral epicondyle of the humerus

across to the electron on so to the ulna

and the lateral part of the ulna over

here so is a very short little muscle

it's described as as helping with

extension of the forearm at the elbow

joint it also kind of stabilizes the

elbow joint in pronation and supination

and it's described as because it

attaches together this is a synovial

joint so it has a drink capsule it's

described as attachment to the joint

capsule so it puts some tension on the

joint capsule so when you're flexing the

extending the elbow it stops the joint

capsule from getting pinched in here it

stops in pin Djimon right instead of

because joint the joint capsule tends to

be the sensitive bit of the joint so by

putting on the joint capsule it keeps it

out of this this gap here and stops

impingement that's how it's being

described anyways okay one of those

things is a little bit tricky to see

when we dissect but that same cone yes

right there you go how's that those are

the muscles that flex and extend the

forearm at the elbow joint mostly

talking about muscles of the brachial I

think I've probably done most things in

the arm now know that I still something

to talk about quite see you next week to

that

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