in this video we're going to examine the bones of the Upper Limb so the first bone that we're going to encounter from or articulating from the scapula is the humorus so this is the largest and the longest bone within the Upper Limb and it's going to articulate with the glenoid cavity via the head of the humorus so the head of the humorus is sort of this Dome shaped structure and it will articulate if we flash back to the scapula image right here into this pink area the glenoid cavity so if we move down the humoris at the end of the little Dome like structure this is where you have the anatomical neck of the the humorus so it's just called the anatomical neck because it's a little bit narrower than the actual ball area that forms the head of the humorus and so just below that anatomical neck we have these two bony areas called the greater tubercle and the Lesser tubric so these are the sites where rotator cuff muscles are going to attach in between the greater and the Lesser tubal you have this little Groove area called the inter tubercular sulcus so this is where the tendon of the biceps is going to lie and so the biceps are actually going to be attached if we look at the glenoid cavity over here at the super glenoid tubercle so that is the bicep attachment site moving down the bone we have this thickened region around the middle part of the shaft of the humoris called the deltoid tuberosity so this is where the deltoid muscles will attach so again keep in mind that thickened areas of the bone usually represent areas where muscles are attaching because they are appear they are regions where they're under a lot of stress so you tend to get more bone deposition in those areas if we examine the posterior view of the humoris there's actually this um sort of uh oblique Groove area and this is where the radial nerve will track on the ends of the humoris you have uh these condil um these two major Condes so the two major Condes are the trolea and the capitulum the trolea is going to be the site Ofna r articulation and the capitulum is going to be the site of the radius articulation so these are the two bones of the lower arm now there are a couple of Hallmarks here the eping uh epicondilite Focus your attention on these little depressions so you have the ocon fosa and you have the coronoid fosa so these two little depressions are going to be very important because when the olula articulates with the uh trolea you need to have little grooves present for this little bony projection of the Ola called the oloc cranon so the oanon will fit perfectly into the O cronon fosa when you extend the arm if however you are flexing the arm if you are flexing the arm then there's actually a process called the coronoid process that will fit into the coronoid fosa so you're kind of locking in this particular hinge joint it helps to sort of stabilize that hinge joint as for the radius you have the radial fosa that allows for sort of a snug fit during the flexing of the uh arm so let's look at the lower part of the Upper Limb so the uh forearm that's going to consist of the radius and the Ona so the radius represents a lateral bone while the Ona is the medial bone the radius will articulate as I mentioned on the previous slide with the capitulum of the humorus and it actually also articulates if we look at this particular image here with the radial Notch of the Ona so at this location right over here here there's actually two points of articulation between the radius and the Onna there's this area here the radial Notch of the olula so we form the proximal radial joint and then the head of the Ola uh close to the head of the ol at the oler notch of the radius you have a second radial oler joint which we call the distal radier joint and what's really unique we we' already touched upon the O cranon of the Ola within the O cranon you have the trolear notch again this is where the troa of the humorus is going to sort of fit in it has that hourglass shape so it's a perfect little hinge joint uh and then the two bones are connected by this inter oous membrane and so that helps to stabilize the structure of the these two bones and moreover when you sort of pronate so when you're are crossing your trying to show this in the video when you're moving your arm like this what happens is the radius and the olna will cross over each other uh because of this inter oous uh membrane so at the ends so at the sort of lateral ends of the uh radius and the Onna you'll notice that the sort of this different main difference is that the Ola is sort of thicker uh at the humeral end but at the end where the wrists are it's going to be the radius that's going to be thicker so the radius will contribute more to the articulation with the wrist while the olna contributes more with the articulation to the humoris so here we have sort of a blown up view again of the oloc cranon the trolear Notch and then you have sort of that hourglass face of the trolea that cond that is found on the humorus okay and then the radial Notch this is where you're going to have the articulation of the radius we will examine the articulation between the radius Onna and the wrist in the next video