So we're on the home stretch, and today is shoulder day. Our first speaker today is Tom Gill. Tom's a former chairman of this program and knows this test and the prep very well. He's going to give two shoulder talks this morning. Thanks, Bruce, and thanks for having me back this year. So of all the shoulder talks from today, and shoulder obviously has a huge, huge presence on all the tests, but as I review all the different talks and what's been on tests, I would encourage you, if you're going to pay attention to one talk, no offense, Julie, but if you're going to pay attention to one talk today, pay attention to this one. Only because as surgeons, we're going to deal with the second talk that I'm giving on rotator cuff and loss of motion. We're going to do that a lot of time, instability and stuff that you're just doing. Stuff that we do every day, at least in my practice, this talk is not stuff I do every day. And in particular, this is a very kind of complication, things to worry about, things to be concerned about, which is what the test likes to do. Not so much, how do you do a bank card, but if you went to fix something, what do you have to worry about at the inferior part of the capsule, what's the neurovascular risk, et cetera. So with that said, we'll get started. So the main topics today are SC joint, AC joint, fractures, nerve conditions, and vascular conditions. The SC joint, there's a difference between the SC and the AC joint. The SC joint is less constrained than the AC joint. It's truly a saddle joint. It's more unstable. It relies on ligamentous structures. It's got the interclavicular ligaments, the costoclavicular ligaments, and then the sternoclavicular ligaments themselves. Obviously, it's the more important joint simply because of its relationship to the inaudible artery and vein. And the thing to remember is the medial epiphysis of the clavicle is the last diffuse in the body. And it's typically some question where they'll specifically give a 19-year-old hockey player, and they'll show you a picture with what looks like a medial clavicle fracture and just understand that that's actually just a FICE epiphysis that's not yet fused. SC joint, if you're ever given an option of fusing an SC joint, the answer is no. You can't fuse an SC joint. And the reason is because there's 35 to 45 degrees of rotation with shoulder elevation. And you can't do it, unlike the AC joint, where there's only about 5 to 10 degrees of motion. Now, the most important ligament around the SC joint, very, very popular question in one way or another the way it's asked, is the posterior capsule. And if you think about it, it's a pretty easy thing to remember, right? Because if you had to have one structure that's going to be strong to protect you, it's going to be something to protect the clavicle from going and hitting the inaudible artery and vein. So it's going to be posterior. It's going to be the most important for AP stability. On physical exam, typically the majority of SC joint dislocations are going to be anterior. So you're going to see a prominence and an easily palpable medial clavicle. These are definitely the most common. If they'll give a clinical vignette where the patient presents or the athlete presents, they have a hoarse voice, having some trouble swallowing. You look at their arm, and maybe they've got a swollen arm. These are all things that are trying to suggest a posterior SC joint dislocation with compression, as you can see in the little schematic down here between trachea, esophagus, the inaudible artery and vein, et cetera. So in x-rays, the view of choice for an SC joint x-ray is a serendipity view. And the serendipity view is taken by Charlie Rockwood's x-ray tech. Did a poor AP x-ray one time. So goes the story. Too much of an angle. And they noticed that actually it was a great view of the SC joint by mistake. That's why it's called serendipity. But it's a 40 degree cephalic tilt that allows you to get the clavicle over the ribs so you can see the SC joint better. That being said, the CT scan is the imaging test of choice for an SC joint. And it does help differentiate dislocations, fractures, and fissile injuries. And you can see kind of the difference here, where you have the clavicle. This is not, you don't have a serendipity view. Serendipity view is down here. And you can see how your clavicle gets overshadowed by the ribs. This is an anterior dislocation here. This is a normal here, et cetera. So mechanisms of injury. This is classically a hockey type of vignette that you get. But a posteriorly directed force to the anterolateral shoulder is going to lever the clavicle out anteriorly on the medial side. So it's just the way it spins. If you push back over here, it's going to pop out anteriorly medially. And contralaterally, if so, and the athlete sustains a posterior below to the posterior direct shoulder, et cetera, then you're going to get, that's how you get the mechanism for the posterior dislocation. So again, just looking at this little netogram of the SC joint, you can see these thick ligamentous structures, the subclavius. There's some historical reconstructions of the SC joint that involve even the subclavius tendon. The interclavicular ligaments here. One of the questions that also comes up is the SC joint has a full intra-articular disc, almost like a full meniscus cartilage. So if you think about it, we see a lot more patients with AC joint arthritis, even though there's less motion there, than we see with SC joint arthritis, even though there's more motion there. And that's because you have this full disc that actually cushions in the articular surfaces. In managing these dislocations, typically, even just in the office, if it's an anterior dislocation, you can do a closed reduction. But no matter what the options they give you, surgery is never something for an SC joint. And I say never. Obviously, I can't imagine they give you some life-threatening situation. But in general, never pick surgery as a solution for an SC joint question. Typically, they're going to want you to give some kind of non-operative answer. The only time that surgery is going to be indicated as a choice, never for anterior dislocations, is for posterior. And that's usually if they give that vignette of dysphagia, dyspnea, venous congestion, et cetera. That's the only time for an SC joint. And then they still want you to say closed reduction, not some kind of open tendon weave, tendon graft type of procedure. You also always want to have a choice where you can do this in the operating room and theoretically with thoracic surgery standby. If for whatever reason they did ask you about, and I have not seen this recently on any of the tests, but if one about 15 years ago did actually ask about an SC joint reconstruction for an anterior dislocation, there's a couple of different options. You can do a medial clavicular resection. That will come up as a choice, again, for that adolescent with a prominent pain over the medial clavicle, trying to get you to think it's a fracture, but it's really the physis. So they will list that as an option. But you can do a resection for an anterior dislocation. You can do a primary ligamentous repair. Or you can do a reconstruction using either the subclavius, using actually that intraarticular disc. But what they want you to say is kind of a figure of eight tendon weave graft, whether it's allograft or autograft. But again, I mention that only just in case they give you the option. Fractures, as mentioned, sort out physcial injury versus fracture. But the big thing is, if you do have a medial clavicle fracture, rule out a scapulothoracic dissociation. And I'll show you an x-ray in a minute. And a CT scan is very useful. But just think about the, and here's an example of a medial clavicle fracture. But think about the trauma it takes to either break a first rib or have a medial clavicular fracture. And that, by definition, you think of some pulmonary injury or some other kind of, again, scapulothoracic dissociation. Oftentimes, it'll be a motocross type of vignette or a motor vehicle accident. So 18-year-old hockey player, direct blow to the anteromedial clavicle. So thinking direct blow, anteromedial, what's going to happen? I'm thinking that either the clavicle is going to go posteriorly. There's going to be some kind of clavicle fracture. Oh, but 18, clavicle, could this be a physis? So that's a physcial question. That's what's kind of going on in my head so far. Presents with swelling at the left SC joint and progressive dysphagia. So what are we talking about? Posterior blow, dysphagia, swelling, posterior dislocation of the SC joint question. And after that vignette, really, this is all they want to know. What's the primary restraint to anterior-posterior translation? As we talked about, posterior capsule. 13-year-old hockey player now gets a check to the anterolateral shoulder. So that's a hockey vignette. Anterior there, so you're going to lever probably. I'm thinking some kind of anterior medial clavicle dislocation, medial clavicular physcial injury, something like that. Finishes the game, comes pain and swelling. CT scan, x-rays are OK, no displacement, no complaints of difficulty with swallowing or breathing. So really, the only positive finding here is pain and swelling in the SC joint. It's a teenager. The physis is going to be weaker than the ligamentous structures. So they're trying to lead you down that physcial injury here. Now, the AC joint, more arthritis because unlike the full disc of the SC joint, it's only a partial disc in the AC joint. Two sets of ligamentous structures, the acromioclavicular ligaments for AP stability, and then the trapezoid and conoid coracoclavicular ligaments for vertical stability. The anatomy of the joint, actually, despite the hundreds of AC joint injections that I've given, I just never stop to think about why I kind of inject an AC joint the way I do. If you're walking along the clavicle, sometimes it's hard to fall in until you angle your hand. Well, there's a reason. It's because the distal clavicle slopes from, medially, from superior to inferior. So it's got a 25 degree slope. So when you're doing your AC injections, you've got to go in at an angle. Who knew? On these, unlike the posterior ligament for the SC joint and the AC joint, the superior clavicle is the strongest. So the way I kind of think about that is just preventing the clavicle from popping up. There's not a lot of dangerous structures posteriorly. But the posterior capsule is kind of the second strongest. But the superior capsule, strongest for the AC joint. Two of the ligamentous anatomy, this is important when you're doing your reconstructions. But the trapezoid is about 3 centimeters. But the trapezoid is about 3 centimeters medial from the AC joint. The conoid about 4 and 1 half centimeters medial. And there's less than 10 degrees of motion at the AC joint itself. Now, the anterior translation, and this is Xavier Wu's work, but anterior translation of the AC joint is inhibited by the inferior capsule. Posterior translation by the superior and the posterior capsule. Now, the way I remember that the superior and posterior are kind of the most important, think about what we do when we do an arthroscopic distal clavicle incision. What do you do 100% of the time? You take out the inferior ligaments. So if they were that important, we wouldn't be doing that. We wouldn't be able to do that. So superior and posterior, more important than inferior. Mechanism following the direct blow to the point of the acromion, or onto the acromion itself, driving the whole scapula down. Rockwood's classification is important only in that it's less important that you can actually rattle off the difference between 4, 5, and 6. But you do need to know what the difference is. One's posterior, one's the inferior, and then one is a very high one. The best questions, the questions they tend to ask the most, there's two different types of questions they'll ask the most. What do you do for a type 3? Are you going to operate on it right away or not? Typically, the answer is no, don't operate on it right away, unless they say weakness, severe pain, painful clicking, et cetera. But typically, type 3 is going to be non-operative. And then type 5 is surgery, which is basically an exaggerated type 3. The other question that will come up a lot is, which of these types of injuries causes post-traumatic arthritis the most? And if you think about it, 4s, 5s, and 6s are not going to be the answer because the articular cartilage is no longer in contact with each other. They're dislocated. So there's not going to be arthritis in that situation. Type 3s, excuse me, 3, 4, 5, 6. And type 1 that has both sets of ligaments intact, there's not going to be a whole lot of motion, so that's not going to be the answer. So the question is going to come up, it's always going to be a type 2 type of AC joint injury has the most risk of future arthritis. So type 1, just to run through briefly what they all are, type 1 is going to be a partial AC ligament tear, normal x-rays. Type 2, as we talked about, the highest risk for AC joint arthritis, disruption of the AC ligaments with intact CC ligaments. Type 3 is tearing of both the AC and the CC ligaments. Type 4 is going to be a posterior dislocation. I can't imagine they're going to ask you this question or show you one. If they do, they'll show you a CT scan. But the answer is going to be ORIF. Type 5 is on the test a lot. They want you to fix it. It's irreducible. So if they'll say it's got a prominent distal clavicle and as the clinician, you're unable to reduce it, it's trying to tell you that it's a type 5. And a subcoracoid dislocation, they're not going to ask you about. But if they did, it's going to be fix it. So on exam, prominent distal clavicle. It's really inferior scapular displacement. The key is how stable or unstable is it. And it has a button to hold through the delto trapezial fascia. So on exam, when you see questions about AC joint, just remember the sternoclavicular joint's still attached. So what else is going on with that AC joint injury? Is there an SC joint problem? Is there a cuff problem? What about the suprascapular nerve? There's a lot of overlap with AC joint pathology and slap tears as well. So where serendipity view is the answer of choice for imaging of an SC joint, a Zanka view is the X-ray of choice for an AC joint problem. And unlike the 40 degree tilt, this is simply a 15 to 20 degree tilt cephalad to be able to look at the AC joint. And the normal coracoclavicular distance is 11 to 13 millimeters. And it's theoretically greater than 25% increase in that distance is significant. Axillary views can be helpful if you look at what I talked about before, a type 4 dislocation. Here is the acromion. Here is the clavicle. Here's where they're lined up. So they really get a need to give you a CT scan if they're going to ask you a question about a type 4, a type 5, a type 6, a type 7, a type 8, a type 9, a type 10. So they're going to ask you a question about a type 1, a type 2, a type 3, a type 4, a type 5, a type 6, a type 7, a type 8, a type 9, a type 10, a type 10. So they're going to ask you a question about a type 1, a type 2, a type 3, a type 5, a type 6, But, the answer for the test is non-operative treatment acutely for type 3s, and there's almost guaranteed to be at least one or two questions on type 3 injuries on this test. The reason for that is if you look at kind of the need for further surgery, if you've had surgery, certainly it's a higher indication, higher risk of infection, and the strength really is not that different. The only downside to no surgery for these is the deformity. Infection is certainly greater with surgery than non-operative treatment. And then, for type 3s, the way they might take you through a vignette, just a couple of things. Initially, if they don't give you some kind of bad physical presentation for the patient, non-operatively. If they'll say it's been a year, still symptomatic, it doesn't matter whether you do it acutely or chronically, you're going to get the same results. That's why they want you to wait. And if they talk about the patient's upset with their deformity, it's overhead athlete or a heavy laborer, clicking with cross-body adduction, pain, those are the buzzwords for wanting to fix it. Do not pick as a choice for type 3 distal clavicle excision alone. That's almost always on there. Reason being is that leads to further instability of the AC joint. And typically, Weaver-Dunn is more of a historical type of option now, again, want that soft tissue reconstruction of the tendon graft. Coracoid transfer, I saw this on one test probably about 10 years ago. Haven't seen it since. Again, it's more of a procedure of historical significance. So in summary, don't fix type 3s acutely. If you do an acute repair, if they lead you down that road, it's a primary repair with some kind of CC fixation. You never just repair the ligaments alone. For chronic repairs, I would say they shouldn't be asking about a distal clavicle. But leave the distal clavicle alone if it's an option. Reconstruct the ligaments with a soft tissue graft. And then the last AC joint problem, if you get a vignette about a weightlifter and shoulder pain, think distal clavicular osteolysis. And then the final treatment being injection. Those are the kind of things that will come together. All right, so 42-year-old male, painful OA of the AC joint, unresponsive to non-operative. A distal clavicle excision is performed. All right, so when doing this procedure, what is the most important ligament to preserve to prevent posterior AC instability? So remember, we always take out the inferior ligament. We get rid of C right away. Anteriorly, ligament is not going to stop posterior, so it's going to be something with a posterior ligament in it. So it's got to be A, C, or E. And then the superior ligaments are the strongest. So it's going to be superior and posterior. 29-year-old surgeon skiing, she injures her dominant shoulder, comes to your office. Here's her x-ray. So this is a type 5 AC dislocation. She remembers 4s, 5s, and 6s we're going to fix. So we're going to look for some kind of fix down here. Injection, no. Sling, no. Early range of motion, no. Modified weaver done, pretty much historical at this point. So it's going to be, see the vague, the general way in which that ligament or that answer is given. Open stabilization with repair. It's not telling you how to do the stabilization because it's controversial, but they do want you to recognize that this should be fixed. 18-year-old rugby player, immediate pain. What is the highest incidence of post-traumatic arthritis? That's just what we talked about, type 2. Which of the following statements correctly describe the contributions of the AC, CA, and CC ligaments in stabilizing the AC joints? So the CA ligament doesn't do anything for stabilizing the AC joint. So the AC ligaments are going to be horizontal, coracocavicular are going to be vertical. So you just look for it down here, you just have to read through them all. And it's E. 26-year-old, feels abnormal motion at the AC joint one year following a distal clavicle resection. So it was done arthroscopically, only about a half a, or 0.5 centimeters of bone was resected with all of the AC joint capsule in a CA distance of one centimeter. So remember the average is kind of 11 to 13 millimeters. So which of the following patterns of instability are the cause of the patient's pain? And because it tells you that the CA distance is only a centimeter, they don't want, and they tell you how much bone came out. Because when I started reading that question, distal clavicle excision, I still have pain, I'm like, ah, okay, too much bone got taken out, the CC ligaments got taken out, they want me to say vertical instability. But they give you the answer, I mean, they take that answer off the table by saying only x-rays were taken, there's less than a centimeter of bone taken, which means the CC ligaments have to be fine, and all of the AC joint capsule got taken as well. And they give you the distance of only one. So vertical is not a problem. So by definition, it's going to be anterior and posterior translation, which is the function of all of the AC ligaments. Make sense? And then clavicle fractures get divided into thirds, medial, middle, and lateral. Medial, we talked a little bit about already. The vast majority of times, we're going to treat these non-operatively unless there's a big posteriorly displaced fracture that threatens the nerve vascular structures. The most common fractures we'll see are these middle third fractures, about 80% of them. Now historically, the answer's always been non-operative treatment for a clavicle fracture. I would say over the past five to seven years, the pendulum has shifted a little bit. If they want you to, say, fix a clavicle, they should give you some parameters or show you an x-ray with at least, and we'll go over it, but at least about 2 centimeters of shortening and 100% displacement. So 2 centimeters of shortening, 100% displacement, and then some kind of pain, deformity, skin problem. They should help you out if they want you to, say, fix a clavicle. In the absence of that, the answer is still, don't fix it. The lateral clavicle fractures, these are just one of those things that I got to remember. I just have to review. Every time I even see one, I just have to go back and look at them again. So we're going to run through what they are because these will come up as well. A type 1 lateral clavicle fracture is lateral to the trapezoid, so lateral to the CC ligaments, does not go into the AC joint. Because it's got anchored medially and laterally, it's a stable injury. It's got a high union rate. It's going to fix without surgery, so you don't need to fix those. Type 2s. Type 2s are medial to an intact CC ligaments. So now I've got the lateral part of that fracture is stable, but the medial part is going to have mobility. So this is going to have a higher rate of nonunion. And for these, you do have to consider an ORIF. And that's divided into A's and B's as well, depending on what part of whether the conoid is involved or not. And then type 3 is usually, if you're going to get a lateral clavicle question, it's going to be about a type 3. Type 3s are intra-articular injuries. So the ligaments are intact. If you look, the AC ligaments on this X-ray, you can see that this distal clavicle is not displaced from the acromion. And then the medial clavicle is being anchored by the CC ligaments. So you have two fracture fragments that are each fixed, but they're fixed differently. So there's still motion allowed at the fracture site. So these actually have the highest risk of nonunion. And they have a risk of post-traumatic arthritis, which is because it goes into the AC joint. So surgery oftentimes is indicated. But with such a small bony fragment, it's tough to get them to heal. And then they will, just like on the medial side of the clavicle, with the late fusing physis, there's oftentimes, if they ask you a pediatric or adolescent question, think It's a very thick periosteal sleeve around the clavicle. And typically, you're going to want to treat most of these nonoperatively in adolescents because that thick periosteum helps the healing process. So risk factors for nonunion of a clavicle fracture, as we talked about, 2 centimeters of shortening, 100% displacement, comminution, or potentially a type 2 distal clavicle fracture. So any of those are the times you want to look for an operative answer to a vignette about a clavicle fracture. Absolute indications are going to be an open fracture, multiple fractures, floating shoulders, neurovascular injuries, et cetera, or if they say nonunion following a previous injury. And then we talked a little bit about the relative indications there. So scapular fractures. The biggest thing to remember about any question about a scapular fracture, almost without fail unless it's specifically a glenoid or a glenoid neck fracture, but certainly any body of a scapular fracture, the answer is going to be treat it nonoperatively is the first thing. But the second thing is rule out associated injuries. So when this guy falls, very, very common, motocross, very common way to get scapular fractures. So the question is going to be, is there a pneumothorax? Is there a brachial plexus injury? What else is going on? So be sure to look through the vignette for something about associated injuries. The reason the body fractures are all going to be treated nonoperatively, you've got the subscap, you've got the infraspinatus, supraspinatus, there's so much muscle and vasculature they're almost always going to heal. So unless, and it doesn't matter if the body even has significant displacement, it's seldom symptomatic. It really only considers surgery for displaced acromial fractures, or as we talked about, the glenoid neck fractures. Relative indications of 5 millimeter step off, absolute indications of 10 millimeter step off. Bony Bankart, still hovering around that 25% threshold, if they say a small bony piece off the glenoid, that's going to be, you do not need to do an ORIF. If they want you to fix a glenoid fracture, they should say something above 25%. The superior suspensory shoulder complex, the only thing to take home about this is, remember it's a ring between the glenoid, the coracoid, the coracoid process, the coracocavicular ligaments, the clavicle, the AC ligament, and then the acromion. So if you have a break in one part of that ring, there's a decent chance there's going to be something wrong in a different part of the ring. And then for proximal humerus fractures, fairly uncommon in the athletic population, usually in older patients. Mostly they should give you, like if they give you an MRI like this where you can see the greater tuberosity, obviously that's going to need to be fixed. But most of them, minimally displaced, can be treated non-operatively. Near classification remains kind of the gold standard for how we're thinking about these problems. As a general rule, 5 millimeters of displacement of a proximal humerus fracture, either of a lesser tuberosity or a greater tuberosity, is going to be the borderline for operative versus non-operative fixation of them. And then scapulothoracic, there was, I did see one question on a scapulothoracic dissociation. This was the x-ray. So I'm going to show you a chest x-ray. So you know, we're looking for pneumothoraces, we're looking for SC joints, looking for ribs. But if you look at this, you can see that the distance from the medial border of the scapula on the left to the spine versus the medial border of the scapula on the right, much longer on the right, and you can see the entire profile of the scapula here where you can't see it here. So just be aware of that. It's not that it's frequently tested, but I did see one question on that. All right, so vascular. This is something, again, where every time I take a test, I have to go back and review it and the dreaded triangular space, quadrilateral space. I mean, there are more questions on quadrilateral space and triangular space, and I can't remember the last time as a surgeon, frankly, that I've thought about it. But you just got to know it, because I promise you there's going to be a question on this, on the test. So think about it. The way to break up the vascular anatomy around the shoulder, three different parts. So you have the subclavian artery, which is coming behind the SC joint. You get to the first rib, and then you get to the axillary artery. You get the axillary artery, you get down to the inferior border of the teres major, and it becomes the brachial artery. The axillary artery has three parts and six branches. The part above the pec minor, below the pec minor, and that's most of the branches. The branches you will come up are going to be from the thyrocervical branch and the coracoacromial artery. Classically, it's you're doing a arthroscopic subacromial decompression, and vigorous bleeding is noted. Not that that's ever happened to any of us, but vigorous bleeding is noted, usually anteriorly. What just got cut? And it's going to be the coracoacromial branch of the thyrocervical trunk of the blah, blah, blah. But it's going to be, it's just, you got to just rattle that off. So structures at risk. Most of these questions, they love, around the shoulder, love to talk about what structures are at risk, complication type questions, et cetera. So the axillary nerve, and this is probably the most common nerve, that and the suprascapular nerve, the two most common ones that are asked about, comes underneath the teres minor, through the quadrilateral space, and around the humerus. So any kind of dissection, you stay above the teres minor, and then don't have too much inferior retraction. The suprascapular nerve, and this is important because there'll be at least one or two questions on suprascapular nerve. It goes to the infraspinatus fossa, three centimeters medial to the posterior glenoid rim. And so the types of questions that are going to come up for a suprascapular nerve are, they'll give you a clinical photo with a supraspinatus fossa that looks good, and an atrophied infraspinatus fossa. And they want you to, and then some combination of, patient's got a labral tear, or something they want you to think, OK, there's a cyst that's coming out. It's going to be in the spinal glenoid notch, and it's going to take out the branch, the infraspinatus, but the supraspinatus branch is still OK. So there's going to be some variation of that. Or there's going to be, you've got wasting of the supraspinatus fossa and the infraspinatus fossa, and they want you to say, OK, it's at the suprascapular notch is where the entrapment is, some kind of release up there is going to be needed, et cetera. They want you to differentiate, know where the branches of the suprascapular nerve come off. And typically, it's going to be a labral tear, maybe there's an MRI with a cyst, and that's going to explain a patient's external rotation weakness. The quadrilateral space and the triangular space, the only saving grace of having to remember these two things is it's pretty much the same structures. It's just one's medial to the other. So triangular, quadrilateral space, teres minor, teres major, long head triceps. That's the answer all the time for the borders of these spaces. The differences on the quadrilateral space, you also have the humerus, and the triangular space, you don't. Through the quadrilateral space goes the axillary nerve and the posterior circumflex humerus artery and vein, whereas it's the circumflex scapular vessels that go through the triangular space. And then typically, with the quadrilateral space questions, it's a thrower, it's pain with late cocking. Sometimes they'll show you an angiogram. The answer is, the way you diagnose it is you have to get an angiogram, and you look for that posterior circumflex vessel being cut off. And then the treatment being you're supposed to release the quadrilateral space. Now that first part of the axillary artery we talked about a little bit, here's that thyrocervical trunk. You've got the suprascapular artery that's coming off, transverse cervical artery. But the artery that's kind of the most commonly asked about is the coracoacromial artery. When you get to the axillary artery, you can see the different branches that comes off the thoracochromial trunk, that's deep to the pec minor, and then axillary artery for most of our shoulder surgery, this is where we tend to, if we're going to injure the axillary artery, this is where we tend to injure it the most. The largest branch of the axillary artery is the subscapular artery, and part of that are the circumflex scapular artery, which as we just said, goes through the triangular space. The primary blood supply to the humeral head, this has come up as a question, is the anterior circumflex humeral artery, so-called one of the three sisters, but the thing is, remember the shoulder is not the hip, so if you get the medial femoral circumflex artery in the hip, you get AVN, you don't get AVN typically of the humeral head. If you cut it, you just get a lot of bleeding. And then vast from a posterior perspective, the artery, know that the artery comes out with the suprascapular vein and artery below the ligament. If you have an axillary artery injury, on physical exam on the vignette, they talk about blood pressure differentials, and classically, if you have a vascular injury to the upper extremity, a lot of times for a sports test, they're going to say it's a baseball pitcher and some kind of emboli, they want you to think of some kind of emboli distally in the arm, but there's going to be some kind of blood pressure differential, et cetera, if you have a traumatic penetrating type of injury. The axillary artery occlusion, as I just mentioned, that comes from repetitive compression of the axillary artery under the pec minor, and it's a very common question, believe it or not, about these thrombi and emboli or pseudoaneurysm. Quadrilateral space, here's that angiogram that I talked about, where you get a kinking of the posterior circumflex artery with abduction, external rotation, it's a fibrous band between the teres major and the long-headed triceps, pain and paresthesias with overhead activity. Sometimes you can get some weakness or atrophy of the teres minor because of where the axillary nerve comes off, but it's going to be a throwing type of story, late cocking, diagnosed with angiography. So just like the axillary artery emboli or occlusion that we talked about, also the Pageant Schroeder syndrome or an effort thrombosis of the axillary vein does come up as well. It's usually a blue, thick, or swollen upper extremity, heavy feeling, and that's caused by venous compression under the clavicle by the scalene muscles, and treatment for that is thrombolysis plus minus releasing the scalenes if you needed to. So 17-year-old baseball pitcher, pain in his throwing shoulder, it's abducted, extended, and externally rotated. So when they throw in extended, that's what I'm starting to think about. Could this be one of those as opposed to just an instability type of question or something like that? Is this going to be one of those quadrilateral spaces? Is this going to be some kind of thoracic outlet or arterial emboli type of question? Point tenderness posteriorly between the teres major and teres minor. So when you hear about something between teres major, teres minor, teres major, teres minor, what do we just say? Quadrilateral space, triangular space. That's where, in my mind, this question is starting to go. Symptoms are duplicated when the arm is held in the cock position for one minute. So there's no part of throwing instability, labrum, rotator cuff, whatever, that if you just hold an arm there where the symptoms persist. So now they're telling you this is a vascular question, just like a thoracic outlet type of question where you're going to get your cut off of your vasculature. Oh, and here it is, no apprehension or instability demonstrated. Well, we already knew that from what they just said. So what's most likely to confirm a diagnosis? Well, teres major, teres minor, thrower, et cetera, it's going to be angiography for quadrilateral space syndrome. Which artery commonly causes bleeding during recessing of the CA ligament off the inner surface of the acromion? It's from that thoracochromial branch specifically, part of the coracochromal artery. And then unfortunately, this picture is kind of what we all wake up to with a dark sweat at night. You kind of just have to draw it like two minutes before you take the test just so you remember it. You can forget about it two minutes after the test, but you do kind of have to remember it for the test itself. You just got to draw it. There's no other way around it. Brachial plexus, but there's a few types of common patterns about the plexus that does come up. Suprascapular nerve, axillary nerve, et cetera. And I put a picture of it in your handout so you can just kind of, when you're sitting on the plane or doing whatever, you can kind of review it and draw it there. So I'm not going to go over it here. Things to remember, though, about important parts of the plexus for the test. Suprascapular nerve. So the nerve passes under the suprascapular ligament, so it comes under, goes first to the supraspinatus, and then around the spinal glenoid notch three centimeters medial to the posterior glenoid rim. So where is it at risk? As we talked about, it's at risk at the notch, in which case it's going to take out both the supra and the infraspinatus. And EMG, although in clinical practice not always as helpful as we'd like it to be, that's still kind of an answer that they would look for if they asked for a diagnostic test for it. And that's typically because of a tight ligament or notch versus a cyst if it's going to be at the spinal glenoid notch. And it's usually getting from a throw or a labral tear, et cetera. And they'll show you an MRI like I have on your handout there. They're looking for you to say entrapment of the nerve there, with the treatment being to decompress it. Here's that suprascapular ligament artery nerve coming below it. Now the axillary nerve comes off a C5-6. And posterior cord from the brachial plexus, anterior to and below the subscap, through the quadrilateral space, and goes to the deltoid from posterior to anterior. Typically a question about a nerve injury, there's going to be a dislocation. So here's a picture of the humeral head. Here's a picture of the axillary nerve. So when this head comes out anteriorly and inferiorly, what's the first structure that's getting hit? It's going to be the axillary nerve. So as Dr. Aylin had talked about from an EMG perspective, there's no use in getting if someone comes in, dislocated shoulder, comes to the sideline or comes to the ER, looks like their axillary nerve is out. You don't get an EMG for at least six weeks. An acute EMG is not going to be helpful. Question if and when do you explore a nerve? I've not seen a question where they want you to explore the nerve and graft it. But typically if they did, they'd want you to say some kind of neurotmesis, an EMG that shows there's discontinuity of the nerve and it's been more than six months. But that should not be a question. Not to beat a dead horse here, but again, it just comes up a lot. So a couple of other ways to think of quadrilateral space syndrome, teres major, teres minor, triceps, humerus. It's usually going to be posterior shoulder pain is what they'll say. MRI could have some teres minor atrophy because that's where one of the branches of the axillary nerve is coming in. Almost always a paralabral cyst. And the posterior circumflex humeral artery occlusion. Burners and stingers, we had a nice talk on, so I'm not going to talk too much about those. The punchline though is this. When the treatment for a burner or stinger is always going to be when the athlete has full strength. If they have some pain, that's okay. They can still go back and play. But it has to be, they have to say return of full strength. If they say no pain and just mild weakness, they have to stay out for the purpose of the test. And I would be surprised if that's not one of the questions. I call this the Bigfoot or the Yeti of the shoulder. Some people believe in it, some people don't. But unfortunately they ask a lot of questions sometimes, so you have to know what it is. Thoracic outlet. Typically the symptoms occur because compression of the neurovascular structures through the scalenes and the first rib. Ulnar paresthesias, so they've got to tell you that there's ulnar-based paresthesias in the hand. It varies with arm position, but especially with overhead and extension of the shoulder. Adsense test is opening and closing your fist, feeling the radial pulse if it goes away with abduction external and rapid opening and closing. That's the vascular phenomenon that really should be the pathognomonic physical exam side for thoracic outlet. There can be a pan-coast tumor too that could compress it. The chance of them asking that on the exam should be very, very low, and I have not seen that as a question. But in case they give you a differential diagnosis, that would be one of them. Treatment for thoracic outlet, rehab, rehab, rehab, rehab. Only if they say done a year of rehab, not getting better, persistent symptoms, then the solution is a first rib resection. Scapular winging is another tough one. We see scapular winging a lot, but we probably don't spend as much time as we should thinking about the different types of winging. But very, very common fodder for exam questions, so just run through it here. Trapezius winging, and there's three types of winging, trapezius serratus and rhomboid. Trapezius winging, if you think about it, if the trapezius is out, so the trapezius is going to be attaching here, kind of the super medial border of the scapula, so that should be pulling the scapula proximally and medially. If that's out, the scapula is going to fall away laterally on the superior part. So the lateral border of the scapula is going to be inferiorly displaced or down, and it's going to be due to a spinal accessory nerve problem. And I will pay your tuition to this course if it's not involving a lymph node biopsy in the neck. All right? And I'll give you my email address later. Enough said. Serratus winging. When the serratus is out, now the medial border of the scapula is out. So you're going to have this type of appearance of the scapula. That is due to a long thoracic nerve injury. Rhomboid winging, they should not ask about. It's very, very rare. It's from a dorsal scapular nerve. The treatment, though, will come up. Treatment for lymph node biopsy, spinal accessory nerve out, lateral border of the scapula down. It's an Eden-Lang transfer between the levator and the rhomboids. All right? That is a very, very common question. What is the treatment for trapezius winging? If it's serratus winging, it's going to be a PEC transfer because that will pull the medial border of the scapula back laterally. And typically, long thoracic nerve, whereas the trapezial winging is from neck surgery of some sort or biopsies, serratus winging is going to be from heavy backpack use and constant traction on the shoulder. Parsonage-Turner, commonly asked about question, classically it's almost always a volleyball player in the vignette. So if you see a question with shoulder and volleyball and some kind of brachial plexus type of symptom, think Parsonage-Turner, so a brachial plexitis, basically. Self-limited, oftentimes in the history, they'll say the athlete had mono or had some upper respiratory infection and then developed this kind of pain and weakness during a volleyball game. So if they happen to ask, why are they telling me about an upper respiratory infection? Think brachial plexitis. You differentiate that from disc herniation. It's very, very rare to have a disc herniation, especially in a young athlete and especially in a non-contact athlete, so that's going to be rare. Complex regional pain syndrome, pretty rare to get questions about that, but it's usually going to be the typical types of descriptions that they'll give. All right, so 42-year-old man, avid tennis player, dominant shoulder, so he's serving, so it's going to be some kind of overhead activity with it. Plays three or four times a week. Last year, got pain and clicking, especially with his serve and his backhand. So pain and clicking in this situation, I think he's trying to tell us about a labrum. So, full range of motion, posterior joint line tenderness, pain, and crepitus with rotation compression testing. So that's kind of their way of saying active compression, which is their way of saying slap and a positive active compression. Atrophy along the scapular body below the spine. So slap tear, pain and crepitus, they're trying to say spinal glenoid notch cyst, knocking out the infraspinatus. His apprehension testing is negative, but he's weak. So they even told you that this is not an instability problem. They say that the apprehension testing is negative. So the diagnosis is the labral tear caused the cyst, which took out the nerve. Thoracic outlet is uncommon, but I told you, there's going to be questions about it, though. But possibly, this is, how does this get on a test? It's uncommon, but possibly under-recognized, but we're going to ask you about it anyway. Complication of clavicle malunions and nonunions. It is most often the result of. So what is it? We would love to say A, but in fact, it's compression from hypertrophic fracture callus. 45-year-old woman, right shoulder pain, five months with overhead activity. Eight months ago, she underwent a lymph node biopsy. Stop reading. Stop reading. What is the answer? Spinal accessory nerve. Next question. 19-year-old hockey player struck from behind and hits the crossbar. So this could be anything. This could be an SC joint question. This could be an anterior instability question. This could be some kind of nerve question. Hits the crossbar. That typically tells me there's going to be some kind of violent traction type of injury. Mild pain, but significant weakness. So now I'm thinking more along the lines of some kind of nerve problem. On exam, very little pain and weakness with forward elevation and abduction. So now starting to think more about axillary nerve, right? So abduction, elevation, deltoid. Could this be a subluxation which caused, remember I showed you the picture of the axillary nerve sitting right in front of the subscapular, right in front of the humeral head. Could this be an axillary nerve paraxia from an anterior subluxation and dislocation event? Good strength and no pain. They even tell you with biceps, triceps, external rotation, et cetera. So biceps still has some C5-6 kind of going on in there. So it's not going to be a more proximal injury. And some sensory loss over the lateral aspect. So that's C5 dermatome lateral deltoid. So this is axillary nerve, axillary nerve, axillary nerve. Now which of these answers below could be, and they give you the axillary nerve as one, but they might not say axillary nerve injury. They might give you some other type of question, like what other structures might be involved, what other types of weakness might they have, et cetera. But you know it's going to be some kind of axillary nerve injury from the way it was asked. High school linebacker, dives for a loose ball during a game, unable to move or feel his right arm, right? So when I look at that, I'm thinking either subluxation, is this a subluxation question, dislocation, or is this a stinger, burner type of question? And they tell you, when managing a first time stinger on the sideline, when can they go back? And they give you all these things, but at the end of the day, all it is is just when the strength comes back. They can't, they're not going to say, you can't, anything that says number of minutes is not going to be an answer. Because five minutes, ten minutes, there's no agreement on a specific amount of time. So it's only after strength returns. And the reason they make it a high school is because they want you to be, they're trying to trick you into being more conservative, like he has to be cleared by a neurologist. Well no. You're the team doctor, right? So that's not going to be, we don't have to refer someone to a neurologist for a stinger. So when strength returns. All right, so I'm going to stop there. I've listed my email below. Just like Brian, if you do have a question or if you're looking to collect your refund for your course from the biopsy, let me know. I'll get back to you. Thanks. Thanks Tom, as always, a great job and we'll see you again in an hour.

Tom Gill

shoulder

SC joint

AC joint

fractures

nerve conditions

vascular conditions

ligaments

diagnostic imaging tests