Overview of the Upper Limb

00:01 we do the thorax and axilla as well. The shoulder joint, a lot of theory. I haven't cover it but you need to just go through the slides when you have a minute. You can get questions on the rotator cuff, shoulder joint. You need to understand the glenoid labrum. From the superior part, you have the long head of biceps. From the inferior side, you have the long head of triceps. So, that is the theory. The four muscles of the rotator cuff, you need to know. Painful arc syndrome. Painful arc syndrome is when your supraspinatus tendon gets caught under the acromion process. So supraspinatus initiates the first 15 degrees of abduction. Then the deltoid takes over. Until here is deltoid, and how does this movement happen? Which muscle is working? Supraspinatus deltoid -- Trapezium? Yes, very good, and a bit more? You’re right.

01:23 You’re on the right track. Trapezium, it’s by the rotation of the scapula.

01:27 Lattisimus? That doesn’t work. Trapezium is mainly.

01:32 Beyond this, this gives the scapula rotation rotating on the thorax and this trapezium is pulling it up. It’s also aided by the rhomboids. This is your action of the shoulder.

01:43 But if we have a supraspinatus tendinitis or painful arc syndrome, when it comes to 60 degrees, the supraspinatus tendon gets caught under the acromion process.

01:55 It’s painful, painful, painful all the way up to 120. Now, when you push it more, the tendon moves off the acromion process and it becomes pain free. So that is your painful arc syndrome, 60 to 120 degrees. Brachial plexus, you can get this in any book.

02:21 So that’s why I didn’t go through this, but when you’re revising, you’ll be able to get all this information for you to understand axillary artery, what is on the lateral side, what is on the medial side branches of the lateral cord, posterior cord, branches of the medial cord. Just take a minute for you to orient yourself. You have a lateral cord of the brachial plexus there, axillary artery, medial cord of the brachial plexus, and then you have the ulnar nerve here, brachial artery.

03:09 One anatomical relation they’ll ask you in the exam is, if you go back to the cubital fossa, the most medial structure is the median nerve. Next to that is the brachial artery, but if you go up the arm, if you go up here, it's other way around. So the brachial artery is medial, median nerve is lateral. As it comes to the distal one-third of the arm, they cross over so that the median nerve comes most medial. So that is another anatomic relation.

03:45 Okay. Dermatomes, I’m sure you know this, but I think I have a picture on that. Okay.

03:56 So, you know that is C5, C6. C6 is your thumb and half of the index finger. C7 is middle finger.

04:06 C8 is mainly ring and little. T1, T2. So, C5 to T2 in the limb. If you look here, it will be T3, T4, T5, T6, T7, T8, T9, umbilicus is T10. T11, T12, L1. C3 and C4, where do the C3 and C4 come from? Cervical plexus.

04:40 Very good, yes. This is what we’ll be discussing after the break. When we discuss the head and neck, we’ll cover the C3, C4. So as I said, the brachial plexus is starting from C5. So that’s why the entire arm is C5 to T1, the inside part is T2. Okay. Cubital fossa, that’s a schematic head of presentation. Laterally, you have the brachioradialis. Medially, you have the pronator teres. So, this is the left and the right cubital fossa. Brachioradialis.

05:20 Pronator teres. Median nerve. Brachial artery. Cephalic vein. That’s the tendon of biceps.

05:28 So if you look at, that’s your left arm, medial to lateral, pronator teres, median nerve, brachial artery, biceps, brachioradialis. Okay. There is nothing new. This is just a theory of what we've discussed, their boundaries, contents. Carpal tunnel, we’ve been through it in detail, but this is cross-section. This is all for further understanding and revising if you have the time. But as I said, if you just revise what we have covered this morning, that should be sufficient for your exam.