Arm in Cross Section

00:01 In this lecture, we're going to carry on looking at the upper limb and we're going to look at the arm.

00:07 So, let's start off by looking at the cross-section of the arm.

00:14 So, this is important as it helps us to compartmentalize the arm which is the superior aspect of the upper limb.

00:21 It's not the forearm which is more inferiorly located.

00:24 So, we're looking at the region around biceps and triceps.

00:27 It's important though to look at the - in cross-sections to appreciate the compartments that are located.

00:35 So, surrounding all the musculature within the arm, we have a tight layer of fascia, the brachial fascia and that lies deep to the subcutaneous tissue.

00:47 We also have an important bone that runs through the arm and that is the humerus.

00:52 You can see that in the middle of the diagram here.

00:56 And then, running between the brachial fascia and the humerus, we have two intermuscular septums, the lateral and the medial.

01:04 And this helps to separate the arm into two compartments.

01:08 Here on the screen above, we have the anterior compartment.

01:12 So, this arm has been cut as if you're laying supine on your bed and your arm has been cut in cross-section and then, you're looking at it by standing at the patient's feet.

01:23 So, at the top of the screen, we can see the anterior compartment and then, at the bottom of the screen, we can see the posterior compartment.

01:31 And you can see there, there are a number of muscles that have been indicated.

01:35 So, anteriorly, we have biceps brachii and brachialis. We can also see a small muscle which is coracobrachialis.

01:42 Posteriorly, we see triceps brachii and we can see within the intermuscular sector, we can see a number of nerve and blood vessels.

01:51 We'll look at these muscles in much more detail moving forward.