So this is actually one of my favorite topics here. It's because, you know, we all work on the shoulder, we're around the shoulder all the time, but this is like the shoulder stuff we don't think about that much, at least that we need to probably think about more, which also means it's something they love to ask questions about. So it's pretty interesting and we'll move through it and like I said, I think you'll kind of remember, I think I remember reading that one time before. So first thing, AC joints and SC joints. There's a difference between the two biomechanically and atomically and therefore, as far as what pathology we see with them. The sternoclavicular joint, diarthroidal joint, but the difference between it and the AC joint is the SC joint has a full intra-articular disc. Okay, so why do we care about that? Well, if you've got a full disc, think of it as like having a full meniscus. We see less arthritis in the SC joint because it's got a full disc. AC joint, it's only got a partial disc, so you end up seeing more arthritis, make sense? All right, so it's one thing to remember. Also, it's a true saddle joint, so it's unstable and it's very dependent on the surrounding ligamentous structures. You've got the anterior and posterior capsule ligaments, the interclavicular ligaments, and then the acostoclavicular ligaments. The other key thing to remember in the AC joint is full disc, less arthritis, but also that it is the medial epiphysis is the last epiphysis to fuse in the body. So when you start getting asked about medial clavicular traumas and things like that in teenagers, don't jump to fracture. It's typically gonna be an epiphyseal type of injury or question, so keep that in mind. The other thing is there's more motion around the SC joint than around the AC joint. So I'm 35 to 45 degrees of rotation with forward elevation and extension. And as a result of this motion, again, everything we'll present, there's a reason we're presenting it here. The reason to remember there's that much motion is fusing the SC joint is never an answer to anything. There's too much motion that's needed at the SC joint. Now, questions for both of these joints, there are always gonna be some variant of what are the most important stabilizing ligaments of the joint. So the SC joint, it's gonna be the posterior. Now, rather than just remember that, that kind of stands to reason, right? What's sitting right behind the SC joint? The aorta, the subclavians, critical structures, right? So it better be that those posterior ligaments are the strongest to prevent displacement of the clavicle into them, all right? So posterior ligaments, most important for AC stability. If you have an SC joint dislocation, things to keep in mind. You're gonna have swelling, you have tenderness, but the most important thing to do is check your blood pressures, all right? Check, look for differential blood pressures. Wanna see if it's a posterior dislocation, you worry about compression of the subclavians. Now, for an anterior dislocation, these are the most common. You can see the swelling, you can see the displacement, and it's easily palpable. When it's posterior, you get this little sulcus-type sign, a dimpling in the area. And that's when you think about dysphagia, you think about hoarseness, venous congestion. If you have, as you see here, the posterior clavicle coming and compressing the great vessels. Also, if you have a posterior dislocation, think about associated injuries. What else could be going, because usually a high energy force that went with it. Now, SC joint injuries can be tough to see on regular x-rays, and Charlie Nier's x-ray tech took a messed up AP x-ray one time for him, and he's like, wow, I can see the SC joints. So he called it the serendipity view, because it was serendipitous that because they messed up the angle, they were able to see the SC joint. So a serendipity view is the view of choice for an SC joint, 40 degrees cephalic tilt. And on a serendipity view, if it's an anterior dislocation, the clavicle will look higher. If it's a posterior dislocation, it'll look inferiorly. But the imaging modality of choice for an SC joint is a CT scan. Mechanism of injury for an anterior dislocation of the SC joint, it's usually gonna be a posteriorly directed force on the anterolateral aspect of the acromia. So it's just gonna pivot, right? So you're gonna push the lateral clavicle back, and it's gonna pop the medial clavicle out, and vice versa for a posterior dislocation. When you have a dislocation for the evaluation, in addition to your exam, we talked about differential blood pressures. Plain films can be tough to see, but again, you can see these ligaments here, the SC ligaments, the interclavicular ligaments. You have the subclavius muscle, and you have that full disc, intraarticular disc right here. Management, anterior much more common, non-operative, non-operative, non-operative. Don't elect to fix an anterior SC joint for this test. Even if it kind of has, the most common thing that'll happen is it'll re-dislocate. You don't even have to try, you can try a simple reduction in the office, but you don't go to the OR to reduce an anterior dislocation. But avoid surgery. Posterior is a different story. Again, risk of vascular injury. They want you to do a closed reduction of a posterior dislocation. They want you to do it in the OR, and you gotta do it with a thoracic surgeon, either in the room or available. Those are the three treatment points to remember. You're probably not gonna be asked about a surgical measurement, but if they do want you to, just to be aware of what the options are. Straight medial clavicular resection, primary ligament repair, moving the subclavius. They've even used the disc to help stabilize. But the treatment of choice, if they say irreducible, persistent symptoms, it's a figure of eight weave, a figure of eight tendon graft is what they want you to do. Now, as we talked about, the medial epiphysis is the last to fuse. And typically between 20 and 25 years of age. Typically, it's gonna be a fissial fracture. And when you see a fissial fracture, again, any medial clavicular trauma, think of associated injuries, including scapulothoracic dissociations. And this is where a CT scan comes into play very well. You can see the fleck there of the medial clavicle. So an 18-year-old hockey player, direct blow to the anteromedial clavicle. So that's gonna drive the clavicle posteriorly, okay. Swelling of the left SC joint and progressively worse dysphagia. So they're telling you it's a posterior dislocation. But then it says, what structure is the primary restraint to AP translation? This is gonna come up. Well, we just talked about that. It's gonna be posterior. So here's the posterior dislocation. Because the posterior ligament's gonna protect the posterior structures. 13-year-old hockey player, check to the anterolateral shoulder. So that's getting pushed back. So I'm thinking already, is the medial clavicle coming forward? Finishes the game. Comes, has pain and swelling in the SC joint. You don't see any obvious displacement. Has no complaints of difficulty with swallowing or breathing. So mechanism is an SC joint injury. Posterior directed to the anterolateral shoulder. Probably an anterior, you're thinking first, well is this an anterior dislocation that then spontaneously reduced? They tell you there's no dysphagia, so it wasn't posterior. But how old is he? 13. Okay, so this is gonna be a fissile fracture that probably reduced. Now as we talked about, the AC joint, unlike the full disc, this is only a partial disc. And as a result, the AC joint is more prone to arthritis. You have the AC joint capsule, which is gonna be your primary restraint to horizontal stability. And then your conoid and trapezoid ligaments, which are gonna be your constraints to vertical stability. And just remember as we do our injections, you don't go straight into an AC joint. You have to angle from supralateral to inframedial because it's an oblique joint. Now again, what capsule, and this will come up in various different ways, what is the strongest part or the most important part of the AC joint? Well first it's gonna be superior and then it's posterior. And the way I remember that is how do most of us do distal clavicles arthroscopically? By definition, when you do an arthroscopic distal clavicle incision, what do you have to resect? Your inferior ligaments, right? So if that was the most important ligament, we wouldn't be doing a lot of arthroscopics. So that's how I remember, we tend to leave the superior ligaments, that's gonna be the most important. And then the CC ligaments, the conoid and trapezoid. The conoid is three centimeters, three centimeters from the lateral clavicle. The conoid's about 45 millimeters from the lateral clavicle. Also important because when you're doing a distal clavicle incision or doing a CC joint reconstruction, you wanna know the anatomic areas where you're gonna be, first of all, how much clavicle you can take without causing instability, and second, where to put your graft. Less than 10 degrees of rotational motion around the AC joint. Biomechanically, anterior translation is something you rarely see, that's kind of the inferior translation, but for posterior translation is the superior and then the posterior capsule, which are the most important. And for superior translation, those CC ligaments, that makes sense just based anatomically where they are. So unlike an SC joint injury, which is either gonna be a direct below laterally and it's gonna be a levering of the SC joint, AC joint injuries, direct blows on top of it. So, and direct on the point of the shoulder, right on the acromion, driving the, it's not driving the clavicle up, it's driving the shoulder girdle down. Six different types of AC joint dislocations. I would say you don't have to know the types, but you kind of do, but at least, even if you have to, don't remember the exact number, at least understand what's going on biomechanically. So there's, just group them as types one and two, and then four, five, and six. And then three, we're gonna spend a couple minutes talking about. So groups one and two are just acromioclavicular ligament injuries. One being a sprain, two being an AC ligament tear completely. So an X-ray of a type one is gonna be a partial tear, but the X-ray is gonna be normal, all right? And when that heals, it goes back normally, there's no increased risk of arthritis, it's not an unstable injury. Type two is gonna be where you see the widening on the X-ray, no superior displacement, but because of the fact that it's wider, but it's now, it's unstable, a type two has the most increased risk for late arthritis, and that comes up in a fair number of different ways a lot. All right? Threes, fours, fives, and sixes, where you have displacement, by definition, if the articular surfaces aren't touching anymore, you're not gonna have late arthritis, all right? So that's not an op, that's not the answer. Type three, we're gonna spend a little bit of time talking about, but this is gonna be a rupture of the AC ligaments and the CC ligaments. Treatment of this is the most controversial, so by definition, that's what they're gonna ask you about. And then fours, fives, and sixes, what you don't really have to remember is it posterior, superior, inferior, but just remember, I mean, which is four, five, and six, but just remember, that's what those are. So ones and twos are non-operative, always initially. Fours, fives, and sixes are always operative, and then threes depends how the question's asked. But four is posterior displacement. Five, again, Rockwood was kind of the guy that described all these. He described a five as an ear tickler. That's how high the clavicle goes. And that's gonna be based on the coraco-clavicular distance. And typically, it needs to be, it buttonholes through the deltoid trapezial fascia. It makes it hard to reduce. And a type six is a subcoracoid dislocation. By definition, when you have this, first thing you wanna check, neurovascular exam, et cetera. Make sure there's no subclavian involvement. This needs to be reduced and stabilized. Physical exam, pretty typical. Looking for an AC joint displacement, but again, don't forget neurovascular exam with it. And the question is, when you're trying to differentiate a type three from a type five, remember those are the superior displacement varieties. Three is just kind of less of a five. How unstable is it? If you can reduce it, chances are it's a three, all right? If you can't reduce it, it's probably a buttonhole through the deltoid trapezial fascia. Much more chance that that's gonna need to be treated surgically. And then don't forget cuff injuries, suprascapular nerve injuries, slap tears, et cetera. So you have the serendipity view, that 40 to 50 degree angle for the SC joint. The imaging modality of choice for the AC joint is a Zanka view. 10 to 15 degree cephalic tilt, all right? And ideally, you wanna get both AC joints if you can on one cassette. Normal CC distance, cortical clavicular distance is 11 to 13 millimeters. And if it's more than 25% increase from there, that's significant for instability of the AC joint. You see, these x-rays are weight bearing, but there's not a lot of indication for weight bearing views anymore because regardless of whether it's a type 1 or a type 2, you gotta treat them the same way initially. When you're looking for displacement, here is the axillary view is your choice. Here's your normal clavicle. Here's your acromion, that's well reduced. And then here you can see a posterior dislocation is a type 4 AC dislocation on the axillary view. And again, get the other side for comparison. Management of type 1s and 2s, always non-operative. Return to play, basically there's no risk, it's a pain issue. So when they can tolerate the pain, usually somewhere between one and three weeks they can return. Late arthritis for type 2s. Slings, harnesses, symptomatic only. There's no difference in natural history with or without these devices. And then injections for people that kinda aren't improving initially with IAC anti-inflammatories. Force 5s and 6s, as I mentioned, more painful, but these are the ones you're pretty much always gonna operate on. I'm using always and never in this talk in quotes, just so you know, but just for the indications of your questions, these are the ones they want you to operate on. The kind of controversial part is, should you retain or resect the distal clavicle? They'll tend not to ask you that, but if they do, as we'll go over in a minute, you know, chronic types, you can think about resecting the distal clavicle as well, but usually for the more acute, if you do it more acutely, you don't just because it may destabilize the joint a little bit. But again, it's starting to get in the realm of a little controversy, but just the way to think about it. The different types of repairs that are available. What the kind of treatment of choice is gonna be free tending grafts. This is kind of when Sam Bradford was still in college. This was the classic AC joint type three dislocation. Even so, he went on to make a lot of money. But for type three, even the reason I show him is because high level athlete, thrower, type three, still initially you want to treat that non-operatively. All right, so for this test, there's very few indications to treat a type three, which is an AC joint... I'm sorry, AC ligament, CC ligament injury. Don't choose acute operative repair of type threes for this test. Data is listed there. The biggest difference between the two is just deformity. You know, there's a higher deformity without surgery, but functionally you can see there's actually better motion, but similar strength with surgery versus no surgery. So there's no functional difference between surgery and no surgery. Jim Tobony did the one study that showed the only difference is a slightly decreased bench press with non-operative versus operative by like 5% or something like that. But for the purposes of this test, no functional difference between surgery and no surgery. The complications of surgery, loss of reduction, very, very common, clavicle fractures, especially with these new anatomic repairs, so-called anatomic repairs, double tunnel, trouble with double drill holes in the clavicle. A clavicle fracture is a significant risk. If you look at the outcomes, basically in this one study, even though it's getting a little bit dated now, no reason to recommend operative treatment for a Rockwood type three injury. That's still the case for the test. Surgery has higher complication rate, longer convalescence, longer time away from sports. Treatment, the only time they want you to operate is if they say, sustained a type three dislocation or they showed you an x-ray that shows a type three dislocation. A year ago, still has persistent pain or six months minimum, but still has persistent pain, clicking, can't return to sport. Because I have had that question on self-assessments. That's when they want you to operate and they'll usually say something general like free tissue graft versus pin versus something like that. And the tip, the treatment of choice is going to be for the reconstruction is the soft tissue grafting. For chronically, distal clavicle excision, as we talked about, it can... One of the issues is it can increase instability and especially for a type three, you never want to have distal clavicle excision be the only surgical thing you do. If you're going to resect it, you still have to reconstruct to repair the ligaments. The weaver done where you transfer the CA ligament from the undersurface of the acromion into the lateral aspect of the clavicle, that's got a lower load to failure than the newer techniques. Screws, loops, tendon grafts. Again, tendon grafts is the recommendation. So last talk, everything that was in yellow was the one you want to remember. Just to switch it up and keep you interested, I put this in bold, okay. So and those are the different options there. Gus Mazzocca is the one that's done most of the studies recently on it and this is that, again, anatomic technique we talked about, 30 millimeters, 45 millimeters for where the tunnels would go. Coracoid transfers, don't worry about those for the test. It's just another option I put in for a comprehensiveness. So in summary, don't repair type threes acutely. If you, for whatever reason, have to do a primary repair of an AC joint, it's a ligament repair plus some kind of coracoclavicular fixation and augmentation, not just ligament pair alone. And chronically, you certainly definitely need a free graft. Distal clavicular osteolysis, any patient, any question that starts out young, male, weightlifter, shoulder pain, think distal clavicular osteoarthritis, AC joint. You have pain, adduction, point tenderness, sometimes you see sclerosis on the x-ray if it's chronic. Forty-two year old male referred with a painful OA of the AC joint unresponsive to non-operative treatment. A distal clavicle excision is recommended, all right. When performing a distal clavicle excision, which AC ligaments are the most important to preserve? So this is going to come up, it's on so many of the tests. We talked about that already. You're going to take them out inferiorly, so it's going to be superior and posterior. Twenty-nine year old surgeon falls while skiing. She injures her dominant shoulder, presents to the office two days later with looks like a type 5 dislocation there. So greater than 100% displacement of the AC joint. What's the best management? Now it's not asking about a Bosworth screw. It's not asking about an intramedullary device. It's not asking about an anatomic reconstruction. It's going to be more general. So modified weaver done is not going to be the isolated answer. It's too low a load to failure. Early range of motion, no. This is that 4, 5, 6. You're supposed to be fixing these. Sling immobilization. Immobilization of AC joints does nothing. It's symptomatic only. You're not going to inject this, so it's a general open stabilization and repair of the CC ligaments. No comments on the first line of this, but an 18 year old rugby player collides with the hooker in the scrum. It's got immediate shoulder pain. What type of injury around the shoulder has the highest incidence of post-traumatic OA? Well remember, 4, 5, 6, anything that's completely displaced, the joint surfaces are no longer touching, that's not going to be an answer. Type... So the 3's, 4's, 5 and 6 I should say. A clavicle mid-shaft fracture has nothing to do with the joint. It's what is a type 2 AC joint sprain. How do you describe the contributions of the AC, CA and CC ligaments? Well before even looking down here, a chromioclavicular is horizontal, coracoclavicular is vertical, CA is nothing except theoretically preventing humeral head migration, but that's not what they're asking here. So I'm looking for something that has horizontal, nothing, vertical and if you look here, that's choice E, horizontal, vertical. Twenty-six year old, abnormal motion at the AC joint a year following a distal clavicle excision. So what are the reasons for that? It's either going to be too big a bony resection which took down some of the CC ligaments or it's going to be too many, too much of the joint capsule was removed. So they tell you only 0.5... It should be 0.5 millimeters. It should have been 0.5 centimeters, but that's not a lot to remove. It was resected with all of the AC joint capsule. X-rays show a distance... So basically they're telling you there's no vertical instability here, 11 to 13 millimeters. That should be CC distance. Which of the following patterns of instability of the AC joint would most likely be the source of the patient's complaint? Alright. So if the CC ligaments are there, any option that's giving you superior is not going to be a choice. So we can rule out A and C and D, alright, because there's no vertical instability. They took out the whole AC joint capsule. AC joint is horizontal stability. It's only AP. So I'm looking for something with AP, no superior, that's B. Okay. Clavicle fractures. Medial, middle, thirds. By far the most common is the middle. Medial we already touched on a little bit. Dr. Busconi, so nice of you to show up. Good to see you. Non-surgical treatment is typically going to be the treatment of choice, because think about it. The medial clavicle is so thick, alright, so there's a lot of cancellous bone that can heal, unless it's significantly displaced. Or unless the displacement is going against the neurovascular structures. The middle third is the most common. You do get asked questions from time to time. Is it better to use a sling? Is it better to use a figure of eight brace? What is it? It doesn't matter. No difference between the two. And most... As long as you're kind of roughly immobilizing in some fashion, they're going to do pretty well. And there's one... The indications for mid-clavicle fractures, we'll touch on a little bit, but basically that the pendulum is shifting a little bit. You know, it was always going to be non-operative, but as we'll talk about, now it depends a little bit on the displacement or the amount of shortening. Okay. Lateral clavicle fractures are the ones I always have to go back and review. Um, it's... We see a lot of mid-clavicle fractures. We don't see as many laterals, but those are the ones of course that are the more complicated ones and are great test fodder. So the way you break them down for types one, two, and three is where is the fracture in relation to the CC ligament? Is it medial to the CC ligament? Is it kind of between them or is it medial? So medial, between, or lateral? If it's lateral, it's a type one. So if it's from the trapezoid laterally, but doesn't go into the AC joint, that's a type one. These are stable injuries. Think about it. You've got the CC ligaments attached, so that clavicle's not going anywhere. Medially, the lateral clavicle's not going anywhere because you have your AC ligaments attached. So if it's a fracture between two good firm ligament complexes, that's going to heal well non-operatively. If you look at type twos, type two fractures are going to be medial to an intact coracoclavicular ligament. So these are the most medial. So now, because they are tied down laterally by the AC ligament and the trapezoid, but it's nothing holding it more medially, you get more displacement. So type twos, greater displacement, higher rate of non-union, consider surgery in this regard. Alright. Less displacement laterally, more medially and then type threes are intra-articular extensions. Now, there's two different types of type threes. As a general rule, if it's the ligaments are intact and it goes into the joint, you're going to treat this non-operatively and consider late distal clavicle excision if they still have pain. Because if it's an intra-articular fracture, there's a risk of post-traumatic arthritis and plus because that piece of bone is so small, you can't really get plates and screws that well for primary osseous healing. So you don't lose a lot if it's a very lateral fracture by treating them non-operatively and at most doing a distal clavicle excision. Just like on the SC joint, kids are a different category because they'll have the fissile injury. Laterally at the AC joint, you can get a type four which is a periosteal sleeve disruption because the periosteum of the clavicle is so thick and depending on how much it's placed, it depends on whether or not you're going to operate. It's pretty rare they're going to want you to operate on the clavicle of a kid for this test though. So risk factors for non-union and these are going to be the risk factors that we mentioned for mid-shaft fractures. It's either going to be more than a 100% displacement of the clavicle or two centimeters of shortening. All right. Those are the two indications to fix a clavicle fracture for the test. Absolute indications, open fractures, multiple fractures, floating shoulders, neurovascular, etc. But again, criteria is two centimeters shortening, one to two centimeters of shortening or displacement. Scapular fractures, the key to remember with scapular fractures is looking for associated injuries, pneumothoraces, scapular thoracic dissociations, brachial plexus injuries, etc. Especially when you have a body fracture. Very rare that they'll ever want you to fix a scapular body fracture. There's excellent vascularity. You've got the subscap. You've got the infraspace. You've got all kinds of musculature and vascularity. Scapular body fractures by and large are going to heal. The only time that you're going to fix a body fracture is if it also has an associated acromial fracture or a coracoid fracture that's causing compromise and here's just all the different types of scapular fractures. The indications for RAF is absolutely a 10 millimeter step off or if your humeral head's no longer centered in the glenoid or more than about a 25% bony bank heart injury. Scapular neck fractures, centimeter displacement, 40 degrees of angulation, but the key is, remember, the axillary nerve comes right near that fracture site so make sure you're doing a neurovascular exam. The superior suspensory shoulder complex, remember this ring, so coracoid, coracoid process, glenoid, scapular spine, acromion, acromioclavicular ligament, CA ligament, right? That ring, if you've got a fracture in one place of that ring, look for a fracture in the other part of the ring and that's, again, all the different varieties there. Approximal humerus fractures, look for on your x-ray, especially greater tuberosity fractures are the ones that you're going to be asked about the most. Remember, the supraspinatus and the posterior cuff are going to pull it medially and posteriorly, the fragment. The indications for repair, especially with greater tuberosity fracture, it's going to be about 5 millimeters of displacement and then four part fractures, higher risk of AVN. That's kind of the take home for the near classification there. Floating shoulders, anytime you have disruption of the CC ligaments or the clavicle fractures or the glenoid, basically when the joint is free-floating due to multiple injuries, absolute indication, but for surgery. But when you do see that floating shoulder, think of scapular thoracic dissociation. The way on the x-ray, I had this on one of my tests, you look at the distance, basically from the spine to the medial border of the scapula on the x-ray, the medial border of the scapula on one side and you can see here's the medial border of the scapula. You see much more of the scapular body here. Just tuck that in the back of your head to make sure that you're not missing that. So here's... I always find this kind of interesting because we're working around the shoulder all the time. At least I know I don't spend enough time reviewing the anatomy in my head. So we're going to spend a couple of minutes to review the vascular anatomy and then kind of what goes wrong with it. This is good for our practices, but especially right now it's also good for this exam. The arterial supply to the upper extremity, you can break it into three different parts, proximal, mid, and distal. That gets divided from the subclavian artery, goes on to the first division, is at the first rib. Then you go to the axillary artery which goes to the inferior border of the teres. And then to the brachial artery. So three parts and then we're going to talk about the basically nine different or six different branches for the axillary artery. So three parts. If you look at starches proximally... Sorry, distally, the axillary artery, you're going to have the area above the pec minor, behind the pec minor, and below it. And when you do... The reason we're going to talk about the posterior approach, even though most of us work most anteriorly, anterior is much lower risk. We're around it all the time, but this is where almost all your questions come from. Either posterior approach to the shoulder or posterior anatomy of the shoulder. So we're going to spend a few minutes on that right now. The axillary nerve. The axillary nerve comes out underneath... If you're posteriorly now, talking about not anteriorly where it's under the subscap, but posteriorly, it's underneath the teres minor through the quadrilateral space and around the humerus. And you got to stay above it, above the teres and avoid a lot of inferior retraction when you're working posteriorly. The suprascapular nerve, probably the most tested nerve that you're going to find around the shoulder, comes from the infraspinatus fascia three centimeters medial to the posterior glenoid rim. And you just don't want you to go... They just don't want you to go too medially on the scapula when you're dissecting. And we're going to go over more of the suprascapular nerve anatomy from the front when we get to the nerve area of the talk. So don't worry about that too much right now. But they love these two spaces. Quadrilateral space, triangular space. That's the bad news. The good news is the same structures border them both. Alright? It's going to be teres minor, teres major, long head triceps. The only difference is with or without the humerus. So you have the quadrilateral above, triangular below, and then the humerus is the fourth piece for the quadrilateral space. Through the quadrilateral space, you get the axillary nerve and the posterior circumflex humeral vessels. That's going to be important when you start talking about different vascular anomalies and then the axillary nerve for different nerve entrapments. So let's go back now to the first part of the artery, the first part of the axillary artery. You've got the thyrocervical trunk here. You've got the suprascapular artery which is going to traverse down here to the suprascapular ligament. You've got the transverse cervical artery and the inferior thyroid artery. The second part of the axillary artery comes off the thoracoacromial trunk of which the one you're going to be tested on is the acromial branch because that's the one that bleeds when we do a decompression. And you have the lateral thoracic trunk. And then the third part of the artery is going to be more distally and that gives off the subscapular artery and that comes through the largest branch from the circumflex scapular which goes through the triangular space. But it's the anterior and posterior circumflex artery. The anterior circumflex humeral artery is the major blood supply to the humeral head, but this is not the hip, right? It's not the posterior branch of the medial femoral circumflex. You're not going to get necessarily AVN, but it is if they say what is the major blood supply to the head, it's the anterior circumflex humeral artery. Now posteriorly, considerations from a vascular standpoint. If you look at axillary artery injuries, this has been reported with all different types of fractures and dislocations. The way you know you have an axillary artery injury is differential blood pressures. The scenario, the vignette you're going to hear about for a lot of vascular injuries is usually going to be a pitcher or a baseball player that either has coolness, numbness, swelling in their upper extremity. If it's acute onset, you're going to be thinking more arterial thrombus or emboli. If it's more blue, chronic, exertional, you're going to be thinking more vascular congestion. But axillary artery occlusion occurs because in this position of abduction and external rotation, you get repetitive compression of the axillary artery underneath the pec minor. That can cause thrombosis or emboli or even pseudoaneurysms. Quadrilateral space syndrome, I've probably had on 60 or 70% of my exams, self-assessments, OITEs, and then my research and everything like that. Very, very common question. This is a posterior circumflex artery compression. It goes from a fiber span between the teres major and the long head of the triceps. Pain and paresthesia with overhead activity, but what they want you to know, you might get some atrophy, is it's symptomatic with a late cocking phase of throwing. So abduction, external rotation will kink the artery or compress the artery. The diagnosis is made by angiography, right here. I was referring to earlier the vascular congestion or Padgett-Schroeder syndrome. Heavy feeling of the arm, swelling of the arm, exertional. The vein, the subclavian is getting compressed under the clavicle by your scalenes, so it's a little bit more proximal. Treatment for that is thrombolysis or if it really gets bad, you can see right here, very little, and the dye getting through is a delayed decompression. So, 17-year-old baseball player, pain in the throwing shoulder when it's abducted, extended, and externally rotated. So what's different about that question? Every baseball pitcher, when they have problems, is going to be abducted and externally rotated, whether it's labor, instability, whatever, but this time they threw in extended. That's not a description they normally give when they talk about a pitcher. So that's got me thinking something besides typical instability, labrum, whatever. Point tenderness posterior. So I told you, they want to start thinking posteriorly now. Tender between the teres major and teres minor. That's kind of a gift. They normally don't give you that, but remember those are those two spaces, quadrilateral space, triangular space, always has teres major, teres minor, triceps. Symptoms are duplicated when the arm is held in the cock position for one minute. Again, that's a gift. They're telling you it's vascular because there's no labral, none of our normal sports medicine, shoulder stuff. It's never going to hold up. Pitcher's holding their arm there. It's always a dynamic pain that they're discussing if it's not a vascular phenomenon. So, you think you're happy because you know this is going to be quadrilateral space syndrome, but that's not what they're asking. They're taking it one step further. How do you make the diagnosis? And it's going to be angiography. So it's angiography where you lose the dye with abduction, external rotation. What artery causes bleeding during recessing of the CA ligament during an acromioplasty basically? So that's the one I told you about. It's the acromial branch of the thoracocromial artery. All right. How many people are getting PTSD right now with this picture? I don't know what to tell you. We've got a lot to go over in our talk. Look at it five minutes before your test. I'm serious. I'm not joking. This is what I do. Study it before the test and you can forget it afterwards, but you just kind of have to know the rough branches. So I gave you two different pictures in your handout. Just take a few minutes to look at it. I'm just going to touch on the most commonly tested parts of the brachial plexus, but you just got to look at it. Of all the brachial plexus, the one that's the most important from this test standpoint is the suprascapular nerve. You got to know the anatomy of it. You got to know where it's going to be pinched. You got to know what the ramifications are. So anatomically, suprascapular nerve comes off, and let me just go back for a minute. Suprascapular nerve is going to be fed by the upper portion of the plexus. It's going to travel under the suprascapular ligament, so under the ligament, to the supraspinatus. So if it's going under the ligament, it's got the ability to be compressed. And then it's going to come down after it comes under the ligament around the spinal glenoid notch. So it's at risk here in the notch. When it's proximal, remember, it hasn't fed the supra or infra yet. So if you have wasting, if they present a vignette with wasting of the supra, wasting of the infra, or difficulty with both abduction and external rotation, that's usually going to be more of a proximal entrapment suprascapular notch. When you start talking, as Dr. Bishop was talking about, with labral tears, that's going to be more spinal glenoid notch. This preservation of the supraspinatus, because that's not being entrapped, but you're going to get compression of the suprascapular nerve distal to the spinal glenoid notch. So you're going to pick off the infraspinatus. The treatment for this, again, you see the cyst here. That's when they do want you to do a slap repair, decompress the cyst, et cetera. And here's a view of the suprascapular notch, the transverse of the suprascapular ligament and the nerve coming underneath it with the blood vests. The axillary nerve comes off the posterior cord of the plexus, contributed by C5 and C6. Why is that important? Because when you get an axillary nerve injury, when do you get that? Dislocations. So you might get a story or a question about what is C5, where's the dermatome for C5, lateral shortest. They might say numbness. You do an exam and there's numbness to the lateral deltoid. That's an axillary nerve injury. It's going to pass anterior to, so we talked about a posterior already. Anteriorly, it's going to be below the subscap is where you're going to find the axillary nerve through the quadrilateral space and it's going to go to the deltoid from posterior to anterior. So it's most commonly, here's a view of it right here. Here's the suprascapularis, lesser tuberosity. Here's the axillary nerve right at the inferior. So whether you're doing a split for an open shift, whether you're doing a fracture, whether you're doing a total, it's pretty humbling how close that nerve really is. If you diagnose an axillary nerve injury or if you want to diagnose EMG is the way you have to make the diagnosis, but not before six weeks. You're not going to get changes in EMG before six weeks. And then if no recovery by six months, explore and graft. Quadrilateral space syndrome, teres minor, teres major, long head triceps, humerus. Posterior shoulder pain and weakness. MRI may or may not see atrium from a cyst of the infraspinatus. Sorry, of the teres minor because of the axillary nerve. But again, diagnosis is by posterior humeral circumflex arterial occlusion on an arteriogram and if you make the diagnosis, it's a release of that fascial band. Brachial plexus injuries, these are almost always kind of C5 level injuries where the upper trunk is going to be the most involved with the brachial plexus. The buzz word for returning to play, it's not a matter of time, it's not a matter of findings, it's when there's a normal neurologic exam. And so it's always going to be a high school kid they're going to ask you about. So you have to have a normal neuro exam, full strength, return of full strength and normal neuro exam. And then they can return to play. This is not a concussion where you have to take someone out for a week. Thoracic outlet syndrome, another one of those things that may have seen me, but I don't see it very often. Symptoms from compression of the neurovascular structures through the scalenes and the first rib. Ulnar paresthesias are the hallmark. Arm position, so abduction extension is going to bring it on more. And then the test for it is Adson's test. Adson's test is checking your radial pulse, the abducted arm and the head turned away. The differential, the thing to worry about with that is a pancose tumor that will show up from time to time. I had that as one of my questions one time. Scapular winging is a favorite type of question as well. And you have to know the different types of scapular winging, medial, lateral, etc. But there are trapezius winging, serratus winging, and rhomboid. And I have trouble just memorizing it, but I can reason through what's affected and then what it's going to look like. So here it is. Trapezius winging. If you know your anatomy, you know what's going to happen with it. If trapezius is going to attach here, the supramedial border, if that nerve is out, if that muscle is out, if that's the cause of it, the trap is not going to be pulling the medial border approximately anymore, so that's going to fall away, right? So the lateral border now of the scapula is going to be displaced inferiorly. It's just going to fall down. And rhomboids down here are still intact, so the medial is going to come over. So that's what the trapezius winging is going to be. Trapezius winging, spinal accessory nerve, by definition is going to be something about a lymph node biopsy. Every time. Serratus winging. This is different. Now my trap is intact, so my supramedial border is still close to the spine, but now the long thoracic nerve, serratus anterior, serratus is going to let the medial border go laterally. So trapezius winging, serratus winging. And then much more rarely, if they're really mean, they'll ask about rhomboid winging. It's very rare. That's a dorsal scapular nerve. Now trapezius winging, almost always going to be injured with some kind of neck surgery, knife injury to the neck, lymph node, something about that is the way they're going to get at your spinal accessory nerve injury to the trap. The treatment for trapezius winging is an Eden-Lang transfer. Serratus winging, the long thoracic nerve, serratus anterior denervation, backpacks, any kind of downward, persistent downward pressure on the shoulder, compression, a lot of weight lifting, heavy musculature, also can cause long thoracic nerve injuries. You're going to treat that non-operatively, but if it's not getting better where you have the Eden-Lang rhomboid transfer for the trapezius winging, this is a PEC transfer. And think about that again. Why is it a PEC transfer? It's because you're trying to pull that back, trying to reduce it immediately because it's falling away laterally. So you need something that's going to pull that inframedial border back towards the spine. Oops, sorry. Now some other neurologic issues you're going to see. Brachial plexus neuritis. For whatever reason there's usually something about a volleyball player and difficulty spiking overhead. Volleyball is either going to be something with slap or something with parsonage turner. I don't know why, but it is. It's usually going to be a diffuse brachial plexopathy type of picture and oftentimes they'll say 21-year-old athlete recovering from an upper respiratory infection. When they toss in this little medical tidbit, think about could this be a sequelae of an upper respiratory infection, some kind of infection that's now causing a brachial plexus neuritis. Multiple root levels and you just differentiate it from cervical radiculitis and our favorite complex regional pain syndrome. So, 42-year-old man, pain in the dominant shoulder, tennis player, three to four times a week. And for the last year he has got pain and clicking, particularly with his serve and backhand. He can still play, but not well. On exam, full motion, posterior joint line tenderness. Now, we don't talk about posterior joint line tenderness in the shoulder, but so when they throw that in there, that's when you're going to start getting away from, you know, is this just a labrum or is this what's going on posteriorly that we've been talking about this whole time. They tell you that there's a positive active compression test. So, you know that they have a slap overhead athlete. He's got a slap and then he's got posterior tenderness. What do slaps cause? They can cause spinal glenoid notch cysts. That's going to cause some posterior joint line tenderness. Atrophy along the scapular body. Why? It's the infraspinatus. All right, so I'm getting thinking more and more. This is a suprascapular nerve entrapment by a spinal glenoid notch cyst causing infraspinatus atrophy. Apprehension test is negative, so it's not instability and he's got weakness on external rotation. So, that's going to be a spinal glenoid notch cyst all day long with involvement of the infraspinatus. Thoracic outlet syndrome is uncommon, but it's a complication of clavicular malunions and nonunions. Well, if they're going to tell you that it's because of some kind of fracture, what's going to cause compression? A hypertrophic callus. Okay. Forty-five year old woman, right shoulder pain for five months with overhead. Eight months ago, lymph node biopsy. I can't even read this question anymore. It's going to be spinal accessory nerve. Nineteen year old hockey player struck from behind. Hits the crossbar with the left shoulder. Mild pain and weakness. On exam, very little pain. That's important. Very little pain and weakness with forward elevation and abduction. Great strength, no pain with testing, but he's got some sensory loss where? Lateral border of the shoulder. What feeds that? Axillary nerve, C5 nerve root. I'm sorry, C5 contribution. So more than likely what happened when he hit, he had a dislocation, right? Remember that picture I showed you of where the axillary nerve is right in front? Anterior dislocation, hits the nerve, axillary neuropraxia, tested, loss of sensation on the lateral deltoid. High school linebacker, dives for a loose ball. Can't move or feel his right arm. So when you can't feel your right arm, football, you're going to think some kind of stinger, burner. Okay. When managing a first time stinger burner, when can they go back? And they're good because they say it does not have neck pain. So I'm trying to tell you, don't think about this, don't overthink this as a disc or something like that. Not a concussion. There's not a question being cleared by a neurologist. It's when you have strength that comes back, the high school kid can go back. All right. So I'm stopping here. In your handout, I have a bunch of other questions that you can kind of go over with at your leisure that will kind of highlight a lot of this stuff. But there's a bunch of them there. If you have any questions, you can email me or I'm going to be around as well. Thanks.

shoulder

AC joints

SC joints

injuries

nerve anatomy

diagnosis

treatment options

Dr. Brian Gilchrist

MD