we can now look at our first official appendage the upper limb starting with the humerus the first part of the humerus is the head of the humerus and this is the region that will articulate with the scapula more specifically the head of the humerus has a chunk of articular cartilage on it and that will articulate with the articular cartilage on the glenoid cavity of the scapula some other structures of the proximal humerus the part closest to the trunk are the anatomical neck and surgical neck what this means is that if you can imagine the humerus moving in your pectoral girdle it will rotate around the anatomical neck so it's just behind the head of the humerus but your humerus tends to break at the surgical neck kind of a skinny part inferior to some of the other structures of the humerus specifically those other structures include the Greater and Lesser tubercles this is basically there's a big bump and a little bump those are for muscle attachments as we'll talk about in the next unit in between the tubercles is the intertubercular groove or sulcus if you prefer and just like the tubercles are for muscle attachments so too is the intertubercular groove there's lots of muscles that attach to the humerus because check me out I can move my humerus in a lot of ways and with a lot of strength I'd surprise you I wouldn't surprise you I'm very weak but I know my anatomy ah let's move on on the shaft of the humerus or based on our previous lessons we could say on the diathesis of the humerus weak find the deltoid tuberosity now this is also for muscle attachments and in this case they gave the structure a nice name so that you know which muscle will attach here the deltoid your shoulder muscle will attach here now let's look at some of these inferior structures on the humerus or I should say distal the structures farther away from the trunk include what is it hey what's that little thing doing here that's the ulna the ulna will help us understand these inferior structures because these structures are mostly for bone to attach to the humerus your forearm bones so look at the ulna the owner has I kind of call it a Cookie Monster you know it has a mouth shape on it that's shaped like a C or maybe a you or ulna and that mouth is called the trochlear notch and its job is to fight on the humerus at a structure called the trochlea trochlea means pulley I don't really use pulleys much in my normal life but I could envision a pulley being shaped kind of like flared on two ends and narrow in the middle and then if you wanted to lift a heavy box or something you would throw a rope up over this pulley so that's kind of like how the trochlea and the ulna work the trochlear notch will bite onto this pulley shape and pivot on the true you now the thing is that when the ulna is doing that as you flex your elbow joint and you bring your forearm up really tight these chunks of bone on the ulna are gonna want to jam up on your humerus so there's actually grooves a little foss a little shallow like depressions on your humerus too fit these chunks of bone this top chunk of bone on the ulna is called the olecranon and it will fit into the olecranon fossa on the posterior side of the humerus the lower chunk of bone on the ulna is called the coronoid process and it will fit into the coronoid fossa on the anterior side of the humerus this is better viewed in some of the videos and things you have access to but just try to think of it as the u-shape bites on to the trochlea and then where your fingers and your thumb would dig into the trochlea there are little depressions right there so the one is called the olecranon fossa and when it's called the coronoid fossa that's looking good we're not done yet you could hey what's that doing here a radius just popped up this is the other bone of your forearm and it's gonna sit right next to the ulna so if the trochlea is all about connecting the ulna to the humerus the capitulum is all about connecting the radius to the humerus there's a part of the radius it's called the head and it's going to nestle right up against the capitulum of the humerus so why is it called the capitulum well think of the root cap anytime you see cap like see ap or SEP like CEP you should be thinking head if you put a cap on your head that's your head if you're Captain America you were the head of the Avengers if you're ste capitated you are removed of your head so capitulum is referring to the head and what touches the capitulum the head of the radius pretty good name here's the thing though when you flex your elbow and these bones are getting tight against your humerus the head of the radius is going to need somewhere to go the radial fossa is a little indentation in the humerus for the bony sticky-outy chunks on the head of the radius to fit into again videos are better for this so you'll have access to those finally there are these two little epicondyles poking out of the distal end of the humerus medial epicondyle and lateral epicondyle make sure you know which is medial and which is lateral that's as easy as just finding the head of the humerus the head of the humerus will always point towards the midline of my body so this will always be the medial side I don't want the head of my humerus poking out into space because that won't make a joint okay now we can look at the radius and ulna officially but we've already named a lot of the parts especially on the ulna we started with the trochlear notch so the whole cartilaginous region that will articulate with the humerus we talked about the olecranon that big chunk of bone which by the way is this bony sticky-outy part of your elbow is your elec Renaud and we talked about the coronoid process now I mentioned that the Ola and radius are going to nestle right up next to each other so the head of the radius actually fits into an adorable little pillow on the ulna called the radial notch and because the head of the radius is like a round disc this notch is kind of also shaped like a C the head of the radius will just slide in there on the OL note we also have the owner tuberosity remember a tuberosity is a bumpy or rough patch where muscles will attach and on the bottom at the head of the ulna since they're always trying to name one end of these long bones head so in this case we'll call the distal end the head and we'll find a little styloid process remember a stylus is what people my dad's age use on their blackberries it's probably what you use on a tablet so stylus styloid means shaped like a stylus like a pin okay let's look at the radius we already mentioned the head of the radius just like the ulna has a tuberosity the radius has a tuberosity and if we look at the distal end of the radius we can't call it the head because we already called the proximal end the head so we don't call it anything but we do say look another styloid process this one on the radius now all we do is that there's lots of articular cartilage on the ends of these bones and we slap in the interosseous membrane which is a wide flat ligament helping to stabilize the connection between the ulna and radius so before we finish with the bones in the wrist and hand I want you to notice that the styloid process of the radius and ulna form a shape that's kind of like this makes a big U shape and the styloid processes are going to help capture all of the wrist bones so if you want to know how that arm and the hand are connected it's through those styloid processes and wrist bones and here they are now bones of the wrist in hand there are eight carpal bones they're not the most fun to learn which means we need a mnemonic to study them so I listed a few mnemonic devices on the slide I always went with the old generic one about Sally going to a party but one of my students taught me this one so long - pinky here comes the thumb and I really liked that one because when you say the word pinky you should be on the pinky end of the wrist if you're looking from an anterior view and when you say the word thumb you should be on the thumb side so the key to all of these mnemonics that I know of that start with s is you have to find the first carpal bone that starts with s and that's scaphoid and scaphoid is a pretty large bone in the wrist it's under the radius so you need to make sure you're starting always on the radius side of the carpal bones with the scaphoid and the mnemonic is so long to pinky so maybe my s scaphoid next is lunate so long then triquetrum and last is pisiform so long to pinky and right now I am on the pinky side of the wrist I know this because I started on the radius side and you know what the radius is the radius is rad dude oh yeah did I tell you my one joke yet here's my only joke I know what did the lifeguard say to the hippie oh and I messed it up why couldn't the lifeguard rescue the hippie he was too far out mom thank you that's the only joke you'll get the whole semester so the reason I tell you that joke is rad dude you have to remember rad because the radius is on the thumb side of your arm the ulna is on the other side so if you start this mnemonic on the radius side by the time you get to pisiform you should be on the pinky side so long too pinky and here comes the thumb let's do the other four hamate capitate trapezoid trapezium many of these are named after their GM geometric shapes and have similar names to each other so you just gotta work through them okay now we just named the hand and finger bones the wrist bones were carpals so the hand bones are the metacarpals so when I say hand bones find your wrist and then go distal all of these bones and your palm if you cut open the palm you're gonna see the hand bones those are the metacarpals and those are just named metacarpal one-two-three-four-five starting on the wrist end 1 2 3 4 5 then I've just got my finger bones those are your phalanges or singular is a phalanx now there's different kinds of phalanges you have proximal phalanges middle phalanges and distal phalanges but check out the thumb the thumb over here there's only two bones the thumb only has a proximal and a distal phalanx no middle phalanx so how many finger bones you have 3 6 9 12 13 14 and 14 more in your other hand is 28 and your feet which we'll do later will be the same 56 phalanges in the body