FULL VIDEO: Main muscles of the upper limb - Human Anatomy | Kenhub

Summary

This tutorial delves into the complex anatomy of the upper limb's muscles, categorizing them into shoulder, arm, forearm, and hand regions. It highlights the deltoid and rotator cuff muscles of the shoulder, emphasizing their role in abduction and rotation. Moving to the arm, it distinguishes between the flexor muscles like biceps brachii and the extensor triceps brachii. The forearm's muscles are detailed, with the anterior compartment's flexors and the posterior's extensors, including the supinator's unique action. The hand's intrinsic muscles are also explored for their role in fine motor skills. The script concludes with insights on rotator cuff injuries, their symptoms, and treatment.

Takeaways

• 💪 The upper limb muscles are crucial for movement and can be divided into regions: shoulder, arm, forearm, and hand.
• 🏋️‍♀️ The shoulder region muscles include the deltoid and the rotator cuff muscles, which are essential for abduction, rotation, and stabilization of the arm.
• 🤲 The arm muscles are divided into anterior (flexors) and posterior (extensors) groups, with the biceps brachii and triceps brachii being key players.
• 🙌 The forearm muscles are complex, with the anterior compartment muscles primarily responsible for flexion and the posterior for extension.
• 🤞 The intrinsic muscles of the hand, including the thenar and hypothenar muscles, are vital for fine motor movements and manipulation.
• 🤕 Rotator cuff injuries are common and can result from overuse or acute trauma, often requiring rest, ice, and sometimes surgery.
• 🏥 Clinically, it's important to maintain muscle balance around the shoulder joint to prevent injuries like rotator cuff strains.
• 🔍 The script provides a detailed anatomical review, highlighting the origins, insertions, and actions of various upper limb muscles.
• 📚 Learning about these muscles helps in understanding human movement and is beneficial for healthcare professionals and fitness enthusiasts.
• 📖 For further study, the script encourages visiting Kenhub.com for articles, quizzes, and anatomical images to deepen knowledge of anatomy.

Q & A

What are the main muscles of the shoulder region?

The main muscles of the shoulder region include the deltoid muscle, which is superficial, and the rotator cuff muscles (supraspinatus, infraspinatus, teres minor, and subscapularis) which are deep muscles. The teres major is also a deep muscle of the shoulder but does not contribute to the rotator cuff.

What is the function of the deltoid muscle?

The deltoid muscle is the major abductor of the arm at the shoulder joint, moving the arm away from the midline of the body.

Why are the rotator cuff muscles called 'rotator cuff'?

The term 'rotator' comes from the rotational movement these muscles elicit when they contract, and 'cuff' originates from their positioning as they extend from the scapula and cuff the head of the humerus.

What is the SITS mnemonic for remembering the rotator cuff muscles?

SITS is a mnemonic where S stands for supraspinatus, I for infraspinatus, T for teres minor, and the final S for subscapularis.

Which muscles are primarily responsible for the rotational movements of the arm at the shoulder joint?

The deep muscles of the shoulder, specifically the rotator cuff muscles and the teres major, are responsible for the rotational movements of the arm at the shoulder joint.

What are the main muscles of the anterior compartment of the arm?

The main muscles of the anterior compartment of the arm include the biceps brachii, coracobrachialis, and brachialis muscles.

What is the primary function of the biceps brachii muscle?

The biceps brachii muscle is one of the major muscles of the arm and contributes to movement at both the shoulder and elbow joints.

How does the brachialis muscle differ from the biceps brachii muscle in terms of function?

The brachialis muscle is a large and powerful muscle that acts only on the elbow joint, being the main and most powerful flexor of the forearm at the elbow.

What is the main muscle of the posterior compartment of the arm?

The triceps brachii is the main muscle of the posterior compartment of the arm, acting at both the shoulder and elbow joints.

What are the main actions of the muscles in the anterior compartment of the forearm?

The muscles in the anterior compartment of the forearm are predominantly flexors, with some contributing to other movements such as adduction of the arm and supination of the forearm.

What is the main action of the triceps brachii muscle?

The triceps brachii muscle extends the arm and forearm posteriorly at the shoulder and elbow joints.

Which muscles are considered the main superficial muscles of the anterior forearm?

The main superficial muscles of the anterior forearm include the pronator teres, flexor carpi radialis, palmaris longus, flexor carpi ulnaris, and flexor digitorum superficialis muscles.

What is the unique action performed by the supinator muscle in the posterior forearm?

The supinator muscle produces supination of the forearm and wrist at the radioulnar joints.

How are the muscles of the hand divided?

The muscles of the hand are divided into intrinsic and extrinsic muscles. Intrinsic muscles originate and insert within the hand, while extrinsic muscles originate in the arm or forearm and insert onto the palmar and dorsal surfaces of the hand and digits.

What are the five groups of intrinsic muscles of the hand?

The five groups of intrinsic muscles of the hand are the dorsal interossei, palmar interossei, lumbricals, hypothenar muscles, and thenar muscles.

What is a rotator cuff strain and what are its symptoms?

A rotator cuff strain occurs when the tendons of the rotator cuff muscles become overstretched or torn. Symptoms include pain on lifting or rotating the arm, swelling around the shoulder, and shoulder joint stiffness.

Outlines

00:00

💪 Introduction to Upper Limb Muscles

This paragraph introduces the tutorial on the main muscles of the upper limb, emphasizing the importance of understanding these muscles beyond just their physical appearance. It outlines the plan to discuss muscles by regions: shoulder, arm, forearm, and hand. It highlights the shoulder muscles, including the superficial deltoid and the deep rotator cuff muscles, which are crucial for shoulder joint movement. The paragraph also explains the origins and insertions of these muscles and their roles in abduction and rotation of the arm.

05:02

🤚 Muscles of the Arm and Forearm

The second paragraph delves into the muscles of the arm, divided into anterior and posterior compartments. It describes the biceps brachii, coracobrachialis, and brachialis in the anterior compartment, which are primarily flexors, and the triceps brachii in the posterior compartment, which is an extensor. The paragraph also touches on the anconius muscle and encourages viewers to explore further for a comprehensive understanding of arm muscles.

10:04

🤞 Complexities of Forearm Muscles

This section explores the muscles of the forearm, which are more complex and divided into anterior and posterior compartments with superficial and deep regions. It details the superficial muscles of the anterior forearm, including the pronator teres, flexor carpi radialis, palmaris longus, flexor carpi ulnaris, and flexor digitorum superficialis, explaining their actions and insertion points. The deep muscles of the anterior forearm are also mentioned, emphasizing their role in fine motor movements of the hand.

15:06

🤚🏻 Posterior Forearm Muscles and Their Movements

The fourth paragraph focuses on the posterior forearm muscles, which are primarily extensors. It describes the superficial muscles like brachioradialis, extensor carpi radialis longus, extensor digitorum, and extensor carpi ulnaris, and their roles in extending the wrist and fingers. The deep muscles of the posterior forearm are briefly mentioned, and the unique action of the supinator muscle in producing forearm rotation is highlighted.

20:06

🤲 Intrinsic Muscles of the Hand

The final paragraph discusses the intrinsic muscles of the hand, which are divided into dorsal and palmar interossei, lumbricals, hypothenar muscles, and thenar muscles. It explains how these muscles work together to create fine motor movements, such as abduction, adduction, flexion, extension, and rotation of the fingers and thumb. The paragraph concludes with a clinical perspective on rotator cuff injuries, their symptoms, causes, and treatment options.

🏋️‍♂️ Clinical Notes and Conclusion

This paragraph provides a brief clinical overview of rotator cuff injuries, focusing on strains and their treatment. It summarizes the tutorial by recapping the main muscles and actions discussed, from the shoulder to the hand. The paragraph ends with an encouragement to continue learning about anatomy through various resources, including articles, quizzes, and videos.

Keywords

💡Upper Limb

The upper limb refers to the parts of the human body extending from the shoulders to the hands, including the arm, forearm, and hand. In the video, the term is central as the tutorial focuses on the muscles and their functions within this region. The script discusses how these muscles contribute to various movements and actions, highlighting their importance in daily activities and sports.

💡Deltoid Muscle

The deltoid muscle is a large, triangular muscle that caps the shoulder joint and is responsible for arm abduction. It is named after the Greek letter 'Delta' due to its triangular shape. In the video, the deltoid is introduced as the main superficial muscle of the shoulder, emphasizing its role in the movement of the arm away from the body's midline.

💡Rotator Cuff

The rotator cuff is a group of four muscles and their tendons that surround the shoulder joint, providing stability and enabling a wide range of shoulder movements. These muscles include the supraspinatus, infraspinatus, teres minor, and subscapularis. The video script explains that these muscles are crucial for the shoulder's rotational movements and are often grouped together due to their collective function and anatomical relationships.

💡Biceps Brachii

The biceps brachii is a two-headed muscle located on the front of the upper arm, responsible for flexing the elbow and supinating the forearm. The video script mentions the biceps as one of the major muscles of the arm, highlighting its dual role in movement at both the shoulder and elbow joints.

💡Triceps Brachii

The triceps brachii is a three-headed muscle on the back of the upper arm that extends the elbow. It is a powerful muscle that acts at both the shoulder and elbow joints. In the video, the triceps is identified as the main muscle of the posterior compartment of the arm, emphasizing its role in extending the arm and forearm.

💡Forearm

The forearm is the region between the elbow and the wrist, containing muscles that facilitate wrist and finger movements. The video script delves into the complex arrangement of muscles in the forearm, which are divided into anterior and posterior compartments, with each having superficial and deep regions. These muscles are responsible for the intricate movements of the hand and fingers.

💡Intrinsic Muscles

Intrinsic muscles are those that both originate and insert within a specific region, in this case, the hand. The video script discusses the intrinsic muscles of the hand, which include the thenar and hypothenar muscles, and their role in fine motor movements, such as grasping and manipulating objects.

💡Extrinsic Muscles

Extrinsic muscles originate outside of the region where they insert, such as muscles that originate in the arm or forearm and insert into the hand. The video script explains that these muscles, including those of the forearm, are responsible for the gross movements of the hand and fingers, and they were discussed in the context of their actions and clinical relevance.

💡Supination

Supination is the action of turning the hand so that the palm faces forward. The video script mentions the supinator muscle, which is responsible for this movement, and how it contributes to the complex rotational capabilities of the forearm and hand.

💡Rotator Cuff Injury

A rotator cuff injury involves damage to the tendons of the rotator cuff muscles, which can result from overuse or acute trauma. The video script provides an overview of this common sports injury, discussing its symptoms, causes, and treatment options, emphasizing the importance of proper care and rehabilitation to maintain shoulder health.

Highlights

Introduction to the muscles of the Upper Limb, emphasizing the importance of understanding them beyond just the visible biceps and triceps.

Division of the Upper Limb muscles into regions: shoulder, arm, forearm, and hand for easier understanding.

Identification of the deltoid muscle as the main superficial muscle of the shoulder region.

Explanation of the deltoid muscle's unique triangular shape, resembling the Greek letter Delta.

Introduction to the rotator cuff muscles, including supraspinatus, infraspinatus, teres minor, and subscapularis.

Description of the rotator cuff muscles' role in shoulder joint rotation and stability.

Discussion of the teres major muscle and its distinct role compared to the rotator cuff muscles.

Overview of the main muscles of the arm, including biceps brachii, coracobrachialis, and brachialis in the anterior compartment, and triceps brachii in the posterior compartment.

Detail on the biceps brachii muscle's dual function across the shoulder and elbow joints.

Explanation of the triceps brachii muscle's role in extending the arm and forearm.

Introduction to the muscles of the forearm, highlighting the differences between anterior and posterior compartments.

Description of the pronator teres muscle and its unique action of pronating the forearm.

Overview of the intrinsic muscles of the hand, including their roles in fine motor movements.

Clinical perspective on rotator cuff injuries, including tendonitis, bursitis, and strains.

Discussion on the treatment and prevention of rotator cuff injuries, emphasizing the importance of muscle balance and strength.

Summary of the tutorial, reinforcing the importance of understanding the complex muscle groups of the Upper Limb.

Transcripts

when you think of the muscles of the

Upper Limb you might think I know those

already

everyone knows where their bulging

biceps are we all know how to flex those

maybe you're even aware of your popping

triceps after doing some triceps tips

what about deltoids

you might have even heard of those

before

but if we look a little bit deeper

there's much more to the muscles of the

Upper Limb then it may seem at first

so rather than building up our muscles

at the gym let's build up our knowledge

on the main muscles of the Upper Limb

in today's tutorial we're going to take

a look at some of the main muscles of

the Upper Limb there are quite a lot of

them but don't worry we're going to

break them down into regions to make it

more manageable we will first begin with

muscles of the shoulder region moving

down to the arm the forearm and finally

the hand we will then identify the

different groups of muscles within each

region

as we go along we will discover the main

actions associated with each group of

muscles as well as their anatomical

relations to surrounding structures

so let's Dive Right In and begin with

the main muscles of the shoulder

we're going to focus on six of the main

muscles of the shoulder today most of

these muscles originate at the Bony

shoulder girdle and attach distally on

the humerus

that means most of these muscles cross

the shoulder joint

therefore when they contract movement of

the arm at the shoulder joint occurs

muscles of the shoulder can be divided

into superficial and deep layers

the main superficial muscle of the

shoulder is the well-known deltoid

muscle this large muscle is a bit like

an upside down triangle extending both

anteriorly and posteriorly its wide flat

base attaches at the shoulder with its

apex descending to attach to the arm the

anatomists who discovered this muscle

must have known their Greek alphabet

very well as they named this muscle

after the triangular-shaped Greek letter

Delta

if we were to peel back the deltoid

muscle we would find a group of smaller

but still very important muscles lying

just beneath these four deep muscles of

the shoulder are known as the rotator

cuff muscles you may be wondering why

these muscles are gripped together as

the rotator cuff muscles the term

Rotator comes from the rotational

movement these muscles elicit when they

contract whereas cuff originates from

their positioning and insertion as they

extend from the scapula and cuff the

head of the humerus

the rotator cuff muscles are also

sometimes known as sits muscles

sits is a handy little mnemonic that can

help you remember the rotator cuff

muscles where s stands for supraspinatus

I for infraspinatus t for Terrace minor

and the final s for subscapularis

the rotator cuff muscles all extend to

insert onto the head of the humerus but

it is their Origins that reveal their

differences

let's take a quick look at these muscles

individually

three of the rotated cuff muscles are

located on the posterior aspect of the

scapula the first of these muscles is

the supraspinatus muscle this muscle

sits on the posterior surface of the

scapula within a hollow known as the

supraspinous fossa this attachment is

where the supraspinatus gets its name

just below the supraspinatus we meet the

infraspinatus muscle sitting in the

infraspinous fossa are you starting to

see the pattern here

this is a triangular muscle with a wide

base and a narrow Apex

the last rotator cuff muscle on the

posterior surface of the scapula is the

teres minor muscle the Terrace minor is

smaller than both the supraspinatus and

infraspinatus muscles and sits inferior

to both at the lateral border of the

scapula

in order to see the final rotator cuff

muscle we need to flip the scapula

around so that we can view its anterior

surface

here we find the subscapularis muscle

sitting in the subscapular fossa hence

its name this muscle is the largest of

the rotator cuff muscles and covers

essentially the whole anterior surface

of the scapula

you may have noticed that there is

another muscle on the posterior surface

of the scapula that we haven't mentioned

yet

sitting just inferior to the Terrace

minor muscle we meet the Terrace major

muscle

teres major is one of the deep muscles

of the shoulder it inserts a little

lower on the shaft of the humerus and

therefore does not contribute to the

tenderness rotator cuff

let's take a look at the movements that

occur when some of the main muscles of

the shoulder contract

the large deltoid muscle is the major

abductor of the arm at the shoulder

joint it moves the arm away from the

midline of the body

the Deep muscles of the shoulder the

rotator cuff muscle and the teres major

are responsible for its rotational

movements they work together to

internally and externally rotate the arm

at the shoulder joint

let's now travel down and take a look at

the main muscles of the arm

muscles of the arm and forearm can be

divided into an anterior and a posterior

group

muscles of the anterior compartments of

the arm include the biceps brachii

the coracobrachialis

and the brachialis muscles

the main muscle of the posterior

compartment of the arm is the triceps

brachii

another small muscle that can be

considered both the muscle of the arm

and the forearm is the anconius muscle

however we'll not discuss it further in

this tutorial as this muscle is often

morphologically and functionally glassed

as a continuation of the triceps

if you want to find out more about the

anconius muscle and the other muscles of

the arm feel free to check out our more

in-depth videos on the muscles of the

arm

okay let's now take a look at the

muscles of the anterior arm in a little

more detail

the biceps brachii muscle is one of the

major muscles of the arm its name comes

from the Latin bi meaning two and kaput

meaning head

it has a long head and a short head the

biceps brachii muscle extends over two

joints the shoulder joint and the elbow

joint meaning that it contributes to

movement at both of them

the karako brachialis muscle is a small

muscle that Lies Beneath the biceps

brachii its name is derived from its

origin and location coraco indicates

this muscle's origin at the coracoid

process of the scapula while brachialis

indicates that it is located within the

brachial or arm region this muscle only

acts on the shoulder joint

a final muscle in the anterior

compartment of the arm is the brachialis

muscle

this muscle sits tucked behind the lower

portion of the biceps brachii muscle and

can be quite hard to find

the brachialis muscle is a large and

powerful muscle that acts only on the

elbow joint it is the main and most

powerful flexor of the forearm at the

elbow

now that we are familiar with the

muscles of the anterior compartment of

the arm let's take a quick look at the

posterior compartment

the triceps brachii muscle is the main

muscle of the posterior compartment

as we saw with the biceps brachii which

is a two-headed muscle the triceps

brachii is given its name because it has

three heads here we can see the long

head and the lateral head and peeking

through we can just about make the

medial head the triceps brachii muscle

is a powerful muscle that acts at both

the shoulder and elbow joints

now that we've had a look at the

anterior and posterior muscles of the

arm let's see how they act on the

shoulder and elbow joint as they

contract

muscles of the anterior compartment of

the arm are predominantly flexors

depending on their origin these three

muscles will either Flex the arm at the

shoulder or Flex the forearm at the

elbow

some muscles will also contribute to

other movements such as adduction of the

arm and supination of the forearm

the movement that occurs in the

posterior arm is quite simple

the triceps brachii muscle extends the

arm and forearm posteriorly at the

shoulder and elbow joints

so now that we've had a look at the

muscles of the arm let's move distally

to take a look at the muscles of the

forearm the region between the elbow and

the wrist

muscles of the forearm are a little bit

more complex

just like the arm the muscles of the

forearm are divided into anterior and

posterior compartments

as well as superficial and deep regions

within each compartment

let's begin by taking a look at some of

the superficial muscles of the anterior

region of the forearm first

starting off with the pronator Terrace

the pronated terrorist muscle is one of

the most superficial muscles of the

forearm it has two heads a humeral and

ulna head we can only see the humeral

head here as the ulnar head is hidden

under the muscle belly unlike most

muscles of the forearm it does not

travel down to reach the hand but

instead inserts onto the radius of the

forearm

lying just medial and slightly posterior

to the pronator teres muscle is the

flexor carpi radialis muscle the names

of this muscle give us an idea of where

it's headed carpi in Latin refers to the

bones of the hand while radialis

indicates the radial or lateral aspect

of the hand therefore by this muscle's

name we can presume that flexor carpi

radialis is heading down to the lateral

metacarpal bones

this muscle travels down to insert onto

the ligamentous structures of the palm

of the hand this muscle is extremely

variable and in fact not everybody has

it

you might be able to find this muscle's

tendon if you flex your hand at the

wrist joint if you have this muscle you

should be able to spot three tendons on

the anterior surface of the wrist if

it's absent you'll only see two tendons

the flexor carpi radialis and ulnaris

tendons

the flexocarpi ulnaris muscle lies just

medial to the palmaris longus muscle

much like the flexor carpi radialis

muscle this muscle also inserts at the

metacarpal bones of the hand but at the

ulna or medial aspect

the last muscle of the superficial layer

that we're going to look at today is the

flexor digitorum superficialis muscle

this muscle is the deepest of all the

superficial muscles of the anterior

compartment and lies just behind the

flexor carpialnurus and radialis muscles

it is a large muscle with two heads

let's now move on to the Deep

compartment of the anterior arm

here we meet the flexor pollicis longus

and the flexor digitorum profundus

muscles these muscles are quite small

and their actions weak so they are not

considered main flexors by many sources

however we do cover them in detail in

our other videos

the final muscle that we will look at in

the anterior deep layer is the pronator

quadratus muscle it is the deepest

muscle of the anterior forearm and sits

next to the wrist it stretches between

the distal end of the radius and ulna

hidden underneath layers of deep and

superficial muscles quadratus in Latin

means Square which is reflected in the

shape of the muscle

before we move on to the posterior

muscles let's take a quick look at some

of the movements of the muscles of the

anterior forearm

the muscles of the anterior forearm are

predominantly all flexors as their name

suggests most of the superficial muscles

Flex the forearm at the elbow joint hand

at the wrist and digits at the

metacarpophalangeal and interphalangeal

joints

deep muscles will also Aid in flexing

the hand and digits but do not act on

the elbow joint

muscles positioned medially or laterally

such as flexor carpi ulnaris and flexor

carpi radialis will also contribute to

abduction and adduction of the hand at

the wrist

the pronated teres and pronator

quadratus muscles work together to

produce a twisting motion known as

pronation

so now we're finished with the anterior

group of the forearm let's flip that arm

around and take a look at some of the

main muscles of the posterior forearm

just like the anterior forearm the

muscles of the posterior forearm are

also divided into superficial and deep

regions muscles within this compartment

are known as the extensor muscles as

this is the main action they perform

let's begin by taking a look at the six

muscles of the superficial layer first

the most superficial muscle of the

posterior forearm is the brachioradialis

muscle this muscle can sometimes be

confused for a muscle of the anterior

compartment due to its positioning it

sits on the lateral aspect of the

forearm and is best identified from the

anterior View

it even behaves like a muscle of the

anterior compartment as it flexes the

forearm at the elbow

it is however considered to be a muscle

of the posterior compartment as it is

innervated by the radial nerve just like

its fellow posterior muscles

slightly inferior to the brachioradialis

muscle we meet the extensor carpi

radialis longus muscle whew that was

quite a mouthful

as this muscle's name suggests it is

located to the radial or lateral aspect

of the posterior forearm the longest in

the name might also give you a clue that

this muscle has a shorter counterpart

and that is the extensor carpi radialis

brevis which is almost completely hidden

by the more superficial longus

you might notice that the three muscles

we just mentioned all contain radial in

their names signifying their location

along the radius these three muscles are

the most lateral muscles of the forearm

and are collectively known as radial

muscles

at the mid portion of the posterior

forearm just medial to the extensor

cuffed by radialis longus we find the

extensor digitorum muscle this muscle is

similar to the flexor digitorum muscles

of the anterior forearm it lies

centrally but instead of inserting onto

the Palmer surface of the hand it

travels on the back or dorsal surface to

insert onto the digits

just medial to the extensive digitorum

muscle is the extensor digiti minimi

muscle this muscle travels right down to

the little finger

the last muscle of the superficial

compartment is the extensor carpi

ulnaris muscle much like the extensor

carpi radialis longus muscle the name of

this muscle also gives us a vague idea

of where it is headed carpi meaning the

carpal bones of the hand and ulnaris

indicates the ulnicide or the medial

aspect of the forearm along which it

travels this muscle suits just medial to

the extensor digitorum muscle along the

length of the forearm

we've made it all the way to the Deep

layer of the posterior forearm

generally these muscles are not

considered main muscles of the Upper

Limb as they are smaller and their

actions are weaker so we will only

quickly run through them there are six

muscles altogether

the extensor policy's longest muscle

and brevis

the abductor pollicis longus

the extensor indices

and the supinator muscle which is the

deepest muscle of the posterior forearm

if you want to find out more about the

muscles of the posterior forearm we have

a whole video dedicated to them

let's pause here to take a minute to

look at the movements created by the

muscles of the posterior forearm as you

may have guessed by their names muscles

of the posterior forearm are

predominantly extensors

most of the superficial muscles extend

the hand at the wrist joint and the

digits at the metacarpophalangeal and

interphalangeal joints

the Deep muscles extend the hand at the

wrist joint and the digits at the

metacarpophalangeal and interphalangeal

Joints but do not act at the elbow joint

muscles positioned medially or laterally

such as extensor carpi radialis longus

and extensor carpi al-naris will also

contribute to the abduction and

adduction of the hand at the wrist

there's one unique muscle however and

that's the supinator muscle

the supinator muscle produces supination

of the forearm and wrist at the radio

ulnar joints this movement can be hard

to visualize so why don't you try

producing these movements yourself

okay so we're nearly there

and we've reached our last destination

which is the hand

muscles of the hand can be divided into

intrinsic and extrinsic muscles

intrinsic muscles are the muscles that

originate and insert within the hand

while extrinsic muscles are the muscles

that originate within the arm or the

forearm and insert onto the Palmer and

dorsal surfaces of the hand and digits

we already discussed the extrinsic

muscles of the hand when we talked about

the muscles of the forearm so now let's

focus on the intrinsic muscles

as with the Almond forearm intrinsic

muscles of the hand are also divided

into groups of muscles

the intrinsic muscles of the hands are

divided into five different groups the

dorsal and Palmer interossei

the lumbricals

the hypothenia muscles

and the thinner muscles

let's begin with the dorsal interossei

notice we are now looking at a dorsal

view of the head otherwise known as the

back of the hand

the dorsal interossei muscles are four

short muscles between the metacarpal

bones

the dorsal winter Rossi are numbered one

to four starting at the thumb

the Palmer into rossii come next and as

you can see we have flipped the hand

around again and now we are looking at

the palm of the hand

the Palmer into Rossi are three muscles

located between the metacarpal bones

these muscles can also be numbered one

to three

the third digit does not have an

Associated Palma interosseous muscle

working our way to the next group of

muscles we meet the lumbricals they are

four short hand muscles located between

the digits of the hand deep in the palm

of fascia the lumbricals actually arise

from the tendons of one of the extrinsic

muscles of the hand as we can see here

moving on we come to the hypothena

muscle group

this group is made up of four small

muscles all situated on the medial

aspect of the Palm at the base of the

little finger the four hypothena muscles

are the abducted digiti minimi

the flexor digiti minimi

the opponent's digital minimi

and finally the palmaris brevis muscle

if you take a look at the palm of your

hand you might actually be able to see

an outline of this muscle group at the

base of your little finger this fleshy

prominence is the hypothena imminence

which marks the surface anatomy of these

muscles

we're on the home stretch here we've

arrived at the final muscle group of the

hand the thinner muscles

the thinner muscles are located on the

lateral aspect of the Palm towards the

base of the thumb

they form a fleshy muscle pad in this

area known as the thinner eminence

the then our muscle group also comprises

four muscles

the thenar muscles are the abductor

pollicis brevis

the adductor pollicis

the flexor pollicis brevis

and the opponent's pollicis

do you recognize the Latin word pollicis

that's right all these muscles act on

the thumb

the intrinsic muscles of the hand work

together to create fine motor movements

the lumbricals and interossei work

together to abduct

adduct

flex and extends the fingers

while the Thena and hypothena muscles

abduct adduct Flex extend and rotate the

thumb and the little finger

now that we've had a look at all the

main muscles of the Upper Limb and their

Associated movements let's take a look

at some of the muscles we saw today from

a clinical perspective

we learned earlier about the rotator

cuff muscle group and how these four

muscles were important in rotating and

stabilizing the shoulder if you are a

gym buff or frequently play sports

you're probably familiar with the term

rotator cuff injury

there are three main types of rotator

cuff injuries tendonitis

bursitis

and strains

today we're going to be focusing on

strands

a rotator cuff strain occurs when the

tendons of the rotator cuff muscles

become overstretched or torn symptoms of

the rotator cuff strain include pain on

lifting or rotating the arm

swelling around the shoulder and

shoulder joint stiffness

strains are usually caused by overuse of

the rotator cuff or may occur from acute

trauma to the shoulder joint

treatment of a rotator cuff sprain

includes rest

ice

and a non-steroidal anti-inflammatory

drugs to reduce inflammation

strengthening exercises may also be used

to restore active function and strength

to the tendon on complete rupture of the

tendon surgical intervention may be

necessary

daily shoulder stretches can Aid in

increasing flexibility and strength of

the shoulder joint when stretching it is

important to strengthen the muscles

around the shoulder blade and posterior

shoulder specifically to optimize the

muscle balance of the rotator cuff

we did it we made it to the end

before we finish up though I'm going to

quickly summarize what we learned today

we started today's tutorial by looking

at the main muscles of the shoulder

we learned about the large deltoid

muscle and the rotator cuff muscles

which include the supraspinatus and

infraspinatus the teres minor and the

subscapularis muscles finally we

identified the Terrace major muscle we

explored how these muscles assist in

creating movements of abduction

adduction and internal and external

rotation of the arm at the shoulder

we then move distally to the arm the

main muscles of the arm were grouped

into anterior and posterior groups

muscles of the anterior group consisted

of the biceps brachii the Coco

brachialis and brachialis muscles

we identified the anterior group to be

predominantly flexors of the arm and

forearm the main muscle of the posterior

region was the triceps brachii muscle

and we learned that its main function

was extension

the forearm came next the main

superficial muscles of the anterior

forearm that we had a look at today

included the pronated Terrace the flexor

carpi radialis

the palmaris longus

the flexocarpi alnaris and the flexor

digitorum superficialis muscles

the main muscles of the deep anterior

forearm included the flexor pollicis

longus the flexor digitorum profundus

and the prinator credatus muscles

muscles of the superficial and deep

compartment of the anterior forearm were

seen to be predominantly flexors of the

forearm hands and fingers

then we met the superficial and deep

posterior forearm muscles some of the

main superficial muscles of the

posterior forearm included the

brachioradialis muscle the extensor

carpi radialis longus muscle the extent

cell digitorum and the extensor

carpialnaris

the main muscles of the deep posterior

forearm include

the extensor policies longus muscle the

extensor indices and the supinator

muscle

we learned that the main action of the

posterior muscles of the forearm was to

extend the forearm hand and fingers

finally we came to the hand we grouped

all those little muscles into five

separate groups and explored how each

group created fine motor movements of

the hand we divided the muscles of the

hand into the dorsal interossei the

Palmer into Rossi

the lumbricals

the hypothena muscle group and the

thinner muscle group we learned that the

muscles of the hypothena group included

the abductor digital minimi the flexor

digiti minimi the opponent's digital

minimi and the palmaris brevis muscles

the phener muscle group included the

abductor pollicis brevis the adductor

pollicis

the flexopolysis brevis and the

opponent's pollicis muscles

once we looked at all the main muscles

of the Upper Limb and their Associated

actions we then had a quick look at some

clinical notes on rotator cuff injury

we learned about a strain injury to the

rotator cuff tendon and identified the

symptoms causes and treatment regime for

this injury depending on the severity of

the injury

that brings us to the end of this

tutorial we hope you enjoyed this

tutorial on the main muscles of the

Upper Limb but don't let your learning

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