today we're going over the easiest ways to learn and remember the muscles of the anterior forearm so to start off with there are eight muscles in the anterior forearm and they are divided into three different layers the superficial layer has four of these muscles the intermediate layer has only one muscle and a deep layer has three now to remember the muscles of the superficial and intermediate layer what i want you to do is place your four fingers up like this and then tuck your thumb into your palm so that's in line with your ring finger from there what i want you to do is place your hand over your inner elbow basically with your fingers pointing distally these four fingers are going to represent the four muscles of the superficial layer so all these muscles originate at the medial epicondyle so basically where your palm would be when you're resting it like this and they all insert basically where your fingers are pointing so it gives you a little point of reference now one way you can remember the names of these muscles is with the mnemonic pass fail pass fail all right so again pass fail pass fail now this first muscle represented by index finger is a past muscle so we know it starts with a p and basically it runs right to the radius underneath your index finger and if we imagine it contracting what it would do it would just pronate the wrist so it pronates the wrist it starts with the p this is the muscle pronator teres our second muscle right here as you can see it points basically to the radial side of the wrist it's a fail muscle so we know it starts with the letter f this is the flexor carpi radialis flexor carpi because it flexes the carpal bones and the radialis is because it runs on the radial side of the forearm our third muscle is basically pointing to the palm and we know it's a past muscle so it starts with the letter p this is the palmaris longus so it runs down and inserts and kind of blends into the palmer epineurosis of the hand not everyone has this muscle but most people do now our last muscle right here represented by our pinky finger it kind of runs down it's pointing to the wrist on the ulnar side and it's a fail muscle so we know it starts with the letter f this is the flexor carpi ulnaris so again it flexes the carpal bones flexor carpi and it's ulnaris because it runs on the ulnar side of the forearm now to get specific about the insertion point of the flexor carpi radialis your middle finger and the flexor carpi ulnaris your pinky finger we have a little trick for that too so despite their names they do not actually insert on the carpal bones or on the radius or the ulna so the radialis the flexor carpi radialis goes down and attaches to the base of the second and third metacarpal so you can think of middle finger to metacarpals the pinky finger the flexor carpi ulnaris it goes down and connects to the pisiform the hook of the hamates and the base of the fifth metacarpal so you can think of pinkie tapiform middle finger to metacarpals and that'll hopefully jog your memory about what these insertion points are now let's get to the intermediate layer so the reason we had our thumb tucked in like that is because it represents the one muscle of the intermediate layer so again we have four muscles in the superficial and then one muscle in the intermediate this muscle is the flexor digitorum superficialis and the reason we had it tucked in with the ring finger is because it basically runs in the same line as the palmaris longus so again we place it over our forearm like this it starts at the medial epicondyle like the rest of them it goes down it goes through the carpal tunnel and inserts on the sides of the middle phalanges now one way you can remember that basically is that it's superficial it's not deep enough it's not going deep enough to the distal phalanges it's very superficial so it just goes to the sides of the middle flanges and they can help you remember the insertion point now for the action since it doesn't go to the distal tips it can't bend those dip joints so when it flexes you end up with something like this for the fingers now finally the three muscles of the deep layer you can think about these basically as your punching muscles because they do everything that's needed to the wrist and hand to create a good punch and a good fist the first muscle is the flexor digitorum profundus and it runs from the ulna through the carpal tunnel and inserts on the distal phalanges of the fingers so when it contracts it can curl all those fingers together you can even curl those dip joints and creates the start of a good fist like that now of course we have to get this thumb out of the way and that's the job of the flexor pulses longus that originates on the radius and inserts on the distal phalanx of the thumb and allows you to curl that in all the way again really getting close to a good fist there so if you're basically like this well what's the last thing you need to do we have to turn that wrist over and that's the job of the third muscle the pronator quadratus that starts at the ulna and then connects to the radius and when it pulls it pulls that wrist over and pronates so those three muscles working together flexor digitorum profundus curls those fingers all together flexor pollicis longus curls that thumb in and the pronator quadratus pulls that wrist over and you got basically a good punch there another reason you can think about why it's the punching muscle is because that p in punching can help you remember the names of these muscles because each one has a word that starts with p we have the pronator quadratus with a p we have the flexor pulses longus with a p and of course the flexor digitorum profundus with a p another reason to help you kind of remember those names by thinking of them as the punching muscles now lastly for the innervation the good news here is that most of the muscles are innervated by the median nerve in fact only two of the muscles in the anterior forearm are innervated by the ulnar nerve the first of those two muscles is the flexor carpi ulnaris which is good because ulna is already in the name so you can think of ulnaris and you know it's innervated by the ulnar nerve the second muscle is the flexor digitorum profundus and actually it's divided in half so half of the profundus is innervated by the median and half is innervated by the ulnar so it's innervated by two nerves and i think wow that's really a profound idea innervated by two nerves very profound very deep so that kind of helps me remember that it's two nerves for that muscle and that's the only muscle in the anterior forearm that's innervated by two nerves all right that covers the muscles of the anterior forearm i hope some of that stuff helped you out as always stay tuned because we're gonna cover the rest of the arm as well thanks for watching of course good luck on your next test [Music]