in this video we're going to examine the shoulder or the glenohumeral joint so it is a traditional ball and socket joint with the head of the humorus fitting into the glenoid cavity of the scapula so it is actually one of the most freely moving joints in the body but it sacrifices this free movement for stability so it's not the most stable of joints and it has to be reinforced by a number of ligaments so most of the reinforcing ligaments are going to be on the anterior portion of the joint and the most prominent one is the corico humoral ligament so that's going to interact with the coracoid process of the scapula as well as the humorus so here we have the choroid process and the Cor chooral ligament goes all the way to the greater tubercle of the humoris now there are three other glenohumeral ligaments they're weak they're actually part of the articular capsule so it's mostly going to be the chooral ligament that is going to support the weight of the upper limbs now with the glenoid cavity if we actually uh hop two slides over in the glenoid cavity we have What's called the glenoid laum so the glenoid labrum and we're going to write that over here the glenoid laum represents sort of this bed of fibrocartilage that deepens the cavity a little bit but even though it deepens the cavity in which the humorus is sitting or the head of the humorus is sitting it is really only covering 13 of the head of the humorus so it's very similar to how a golf ball rests on a te very little forces is needed to knock it off which is why we're so dependent on these uh ligaments perhaps the greatest structural component of the shoulder joint are going to be the very ious tendons of the muscle and of those tendons the most important is going to be the tendon of the long head of the biceps so the long tangent of the biceps is going to travel through the uh intertubercular excuse me the inter tubercular sulcus of the humorus so that's the little Groove near the head of the humorus and it's going to secure the humorus kind of just push it up into the glenoid cavity so it's going to and again let me hop over to this particular image here so it's going to here's the tendon of the the the long head of the biceps it's going to eventually interact with the glenoid laum so that interaction is what helps to secure the humoris to the glenoid cavity that interaction between the glenoid labor and the tendon of the biceps additionally we have four rotator cuff tendons from the four muscles that comprise the rotator cuff so the most the largest and the strongest of these muscles is going to be the subscapularis so we're going to look at this particular figure here the subscapularis originates in the sub scapular orosa which is found on the scapula and it's going to interact again with the greater tubercle of the humorus we have the supraspinatus again that will originate with the uh supraspinal fosa and that again interacts with the head of the or excuse me the tubercle of the humoris the other two muscles are the infraspinatus and the teras minor so again these rotator cuff muscles allow for that greater range of motion as well as the stability however the rotator cuff can be uh severely stretched especially if you're doing a lot of sort of circumduction uh and this is sort of the reason why baseball players uh have uh this type of injury is going to be fairly common within them so if we look at overall the reinforcements in this joint the reinfor are going to be sort of weaker on the anterior side because you only have that uh ligament right the right here the corico humeral ligament that sort of stabilizes the anterior part and it's also going to be the weakest on an inferior side because you don't have that many muscles on the inferior side so this is why uh you get a lot of shoulder dislocations when the humoris moves forward and down word