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  • this video was sponsored by kenhub more on them at  the end of the video hello and welcome my name is  

  • patrick and in this video i'll teach you some  of my tips and tricks for remembering all the  

  • skeletal muscles of the upper limb that you would  see in an anatomy class and to make this lesson  

  • more manageable for beginners i'll present  the list in smaller chunks of 4 to 8 muscles  

  • you can find a list of the sections and the time  stamps in the description below and with that  

  • out of the way let's get into the muscles a few of  the muscles that control movement of the arm start  

  • all the way back on the spine so for our first  chunk we'll talk about the muscles that people  

  • usually refer to when they say it's back day the  trapezius is this big muscle that inserts on the  

  • scapula and clavicle but originates all the way  from the base of the skull to the lowest thoracic  

  • vertebrae sometimes you'll see this described  especially in the fitness world as the upper  

  • middle and lower trap muscles but it's important  to remember that they all make up a single muscle  

  • different sections of it just have different  angles of fibers so this one muscle can move the  

  • shoulder in multiple ways but it's still a single  muscle the easiest way to remember this one is by  

  • looking at both sides of the muscle together  it looks like a trapezoid which gives it its  

  • name trapezius the other big superficial muscle is  the latissimus dorsi often just referred to as the  

  • lats it's the widest muscle in the body spanning  from shoulder to shoulder and from the thoracic  

  • vertebrae down to the bottom of the sacrum and all  of those fibers meet up to insert on the humerus  

  • if the lat's name doesn't stick for you then  you can use the latin naming conventions of this  

  • muscle latissimus refers to how lateral these  muscles are and dorsi refers to its location  

  • on the back just like the dorsal fin of a dolphin  if we cut away the superficial trapezius muscles  

  • we'd see three more muscles that originate  on the spine and move the shoulder blade the  

  • rhomboid major and rhomboid minor both originate  on the spine and insert on the scapula helping  

  • us retract our shoulder blades and maintain good  posture the rhomboid major is rhomboid shaped as  

  • the name implies but the rhomboid minor is really  more cylindrical in real life my tip for this  

  • one is to identify rhomboid major first then look  right above it for its little buddy rhomboid minor  

  • also people tend to mix up the rhomboid major  and the serratus posterior superior muscle yeah  

  • they're in similar spots but the rhomboid is more  superficial while the sps is deep the other big  

  • cue is the shape the rhomboid has those straight  geometric edges while the serratus has serrated or  

  • jagged attachment finally a muscle we talked about  in the neck unit the levator scapulae which does  

  • exactly what you think it elevates the scapula but  be careful there are lots of neck muscles in this  

  • area that run superior to inferior the levator  scapulae will be the only one that attaches  

  • vertebrae way high in the neck to the top of the  scapula the next chunk includes the muscles of the  

  • chest and you probably know the root for this one  already pectoralis the big familiar one on top is  

  • the pectoralis major literally meaning big chest  muscle but underneath that is the pectoralis minor  

  • it follows a similar path to the pec major but  doesn't extend all the way to the sternum and  

  • is clearly much smaller hence pec minor as we  move inferiorly we see this cool looking muscle  

  • called the serratus anterior named so because  its jagged pattern makes it look serrated or  

  • sawtooth like a bread knife for those who like to  find these muscles with touch you can feel both  

  • your pec major and your serratus interior contract  when you punch forward with a straight arm  

  • your pec is easy to feel but you may have to press  a little harder near your armpits to feel your sa  

  • finally the intercostal muscles are between  each rib costal is the latin root for rib so  

  • intercostal literally translates to between the  ribs see this video if you want a little more  

  • info on those the next big chunk is the shoulder  joint most of the muscles that move the joint  

  • made of the glenoid fossa and the head of the  humerus the glenohumeral joint the biggest and  

  • most superficial is the deltoid named because it  looks like the greek letter delta a triangle once  

  • you peel away the deltoid you'll find the four  muscles of the rotator cuff what i learned as the  

  • sits muscles the first three the s-i and t can be  easily found on the posterior side of the scapula  

  • and use the big bony landmarks to find their  name the supraspinatus is superior to the spine  

  • of the scapula while the infraspinatus  is inferior to the spine of the scapula  

  • meanwhile the teres minor makes an angle with each  humerus that looks kind of like an m for teres  

  • minor finally the subscapularis the s in the sitz  groups literally means under the scapula if you  

  • think of the scapula like a rock you could pick it  up turn it over and if you looked under the rock  

  • that's where this muscle would be the last muscle  of the shoulder chunk is the teres major which  

  • takes a similar path to the teres minor but as  the name implies something about it is bigger  

  • and actually i don't bother looking at its size  i look at its position it originates further down  

  • the scapula and further down the humerus which  means that this thing has some leverage that  

  • the teres minor doesn't have in fact the teres  major is more like the powerful latissimus dorsi  

  • your pull-up muscle than it is like a rotator cuff  muscle so the teres major is a major mover of the  

  • arm the muscles of the upper arm are a crash  course in latin names and as long as you know  

  • the regional term brachii for upper arm everything  else is intuitive you probably already know the  

  • biceps brachii the two-headed muscle of the upper  arm and the triceps brachii the three-headed  

  • muscle we got brachii to denote the upper arm  and the by and try to denote the number of heads  

  • or seps the coracobrachialis straight up tells you  what it does it attaches the coracoid process of  

  • the shoulder blade to the upper arm likewise the  brachioradialis connects the humerus the upper  

  • arm bone to the radius there's also the brachialis  the stubbiest of elbow flexors honestly i just use  

  • the process of elimination to remember this one  the biceps and brachioradialis had more intuitive  

  • names so the last upper arm muscle has to be the  brachialis finally there's a small muscle on the  

  • back side of the arm that extends the elbowlittle bit it's called the anconeus it's not  

  • as powerful as the tricep so it's a wee accessory  muscle at this point i remember this one because  

  • if you make a cone out of your arm the very tip  is the anconeus i hope you enjoyed the simplicity  

  • in this chunk because the next two are uh more  involved you could say like look at this forearm  

  • all of our human hand dexterity comes at the price  of having a lot of tiny muscles and anatomists  

  • didn't want to give them all fun whimsical names  they get names like the flexor carpi radialis  

  • what's it do it flexes the carpi or hand and it's  on the side nearest your radius the flexor carpi  

  • ulnaris it does the same thing but on your ulnar  side anatomists gave them intuitive names but that  

  • concentrates a lot of multi-syllable muscle names  into the forearm take the palmaris longus a small  

  • muscle with a long tendon that inserts at the  base of the palm for that palmaris part fun fact  

  • quite a few people don't have this muscle on one  of their two hands and some people don't have it  

  • at all i made a video all about that which you can  check out here the pronator teres has a long but  

  • straightforward action name it pronates the arm  pivoting your hand down you can actually palpate  

  • it easily if you put your finger in front of your  medial epicondyle and pronate your hand the other  

  • pronator is a square-shaped muscle all the way  down at your wrist its action pronation and  

  • square shape quadratus give us the name pronator  quadratus these other muscles also use action  

  • plus anatomical region like the flexor digitorum  superficialis it flexes the digitorum or fingers  

  • primarily at the proximal interphalangeal joint  this knuckle closest to your wrist here you have  

  • plenty of other muscles to flex and extend the  small interphalangeal joints but we'll get to  

  • those later now as the name implies if there's a  superficial then there's a deep or what anatomists  

  • call profundus when we're talking about hand  muscles so the flexor digitorum profundus is also  

  • a finger flexor but it's deep to the superficial  version finally there's a special latin root for  

  • thumb it's called pollux so the flexor pollicis  longus is a long muscle that bends the thumb  

  • considering how important it is to be able to bend  your thumb to grip anything it makes sense that  

  • this muscle would have such a big muscle belly  now just like the anterior forearm the posterior  

  • side has superficial and deep sections luckily  they follow the same predictable naming patterns  

  • we'll start from the outside in the anterior arm  had all the flexors so the posterior side has all  

  • the extensors most of the time that leaves us with  mirror opposites like the extensor carpi ulnaris  

  • which follows the same convention it extends  the wrist joint and inserts on the ulnar side  

  • or the extensor carpi radialis longus same thing  it extends the wrist and inserts on the radial  

  • side and while this one is a longus there's also  an extensor carpe radialis brevis that follows  

  • the same rules it's just shorter this muscle is  the extensor digitorum which extends the fingers  

  • it's got a big muscle belly on the forearm  and inserts on the dorsal side of the hand  

  • likewise the extensor digiti minimi extends  a finger but adorably only the tiniest most  

  • minimal finger the pinky and you can feel all of  these too if you put your arm down on the table  

  • you'll feel the different muscles pop up for the  whole hand or just the fingers or just the pinky  

  • it's a great technique to come back to if you're  ever lost on a test when we go a little deeper we  

  • see more action-specific names and the pinky isn't  the only finger with its own dedicated muscle the  

  • extensor indices starts on the ulnar side of the  forearm and is solely responsible for extending  

  • the index finger or forefinger then there's the  thumb again if you spread out your fingers you'll  

  • notice a bunch of tendons around the thumb which  are sometimes called the anatomical snuff box  

  • because you could put some cocaine there and  snuff it a lot clive owen's character in the  

  • nick but there's an anatomic significance  too this snuff box is made of the tendons  

  • that extend and abduct the thumb and these long  tendonous muscles originate on the forearm itself  

  • those muscles are the abductor pollicus longus  extensor polycast longus and extensor polycus  

  • brevis and you'll notice that these muscles insert  at different points on the thumb which helps us  

  • identify them the abductor inserts on the thumb's  metacarpal and has this almost diagonal pull to it  

  • whereas the extensors both longus and brevis cross  over the top of the carpe metacarpal joint at the  

  • base of the thumb the abductor pulls sideways  the extensors pull up from there the difference  

  • between extensor policus longus and brevis is  just the size finally we already saw the pronator  

  • muscles on the anterior forearm so the muscle  that performs the opposite motion must be on  

  • the posterior forearm and it is the supinator  muscle is found all the way up at the elbow  

  • sprawling across the ulna radius and a bit of  the humerus too here's how i remember this one  

  • all of the other muscles of the forearm control  the hand and you can tell because they have long  

  • tendons that insert at the hand but the supinator  only really interacts with the two forearm bones  

  • so supination is the only thing that it can do  the next chunk is the thenar mass a group of  

  • four short muscles that make up the fleshy mass  of your palm collectively they're special muscles  

  • that move the thumb and their names reflect that  because the muscles are named after their actions  

  • my biggest advice is to know your movement terms  and look at the angle of pull the flexor policus  

  • brevis originates at some of the carpal bones and  inserts on the first phalanx and thumb flexion  

  • looks similar to thumb opposition bringing  the thumb and pinky together because of that  

  • relationship the muscle responsible for opposition  is called the opponent's pollicis and is directly  

  • underneath the flexor in reality both of these  muscles work together when curling the thumb like  

  • during writing so it's hard to say that like this  muscle just does this action the next muscle gets  

  • another movement name the adductor pollicis for  this one you just need to know that thumb flexion  

  • is more of a bending while thumb adduction is like  bringing your thumb parallel to the other fingers  

  • from there you can see how the adductor pollicis  just brings the thumb towards the midline finally  

  • the abductor pollicis brevis is the odd one out it  abducts the thumb bringing it away from the palm  

  • so it runs from the medial carpels to the dorsal  side of the thumb and has this giant muscle belly  

  • just slopped along the metacarpal look at it  there's no way that muscle is bringing the thumb  

  • toward the midline it must be an abductor also pro  tip you can palpate the abductor relax your thumb  

  • put your finger on the thenar mass abduct your  thumb and it'll pop up so at this point we've  

  • covered a lot of those hand and finger muscles but  there are still a handful left we had athenar mass  

  • of muscles that control the thumb but we also have  the hypothenar mass made of muscles that move the  

  • pinky remember how we said that opposition is  touching the thumb to the pinky well it takes  

  • two muscles to tingle to finger tango what i'm  trying to say is that the opponent's digitized  

  • minimi is responsible for opposing the pinky thus  completing the motion of opposition it's easy to  

  • see given its diagonal path especially when you  contrast that to the flexor digitized minimize  

  • brevis which pulls directly parallel to the pinky  which curls or flexes it and it's a short guy so  

  • brevis the last in the hypothenar mass is  the abductor digiti minimi this hearty slab  

  • of muscle on the medial side of the hand which  abducts the pinky no surprises there now there's  

  • another misfit muscle near the hypothenar group  called the palmaris brevis it hooks up to a band  

  • of connective tissue called the palmer aponeuresis  and despite its location it doesn't have anything