So we discussed the histological portions of skeletal muscle tissue. Now let's talk about the gross anatomy. And this is really one of our first forays into gross anatomy indicating that it's visible. So anything that's visible in terms of a dissection, we're going to introduce that concept here. Now when you're talking about a skeletal muscle, there's typically two main components. You have the muscle belly, which is what we typically think of when we're thinking of a muscle and then you have the tendon. Now the tendon, remember when we were talking about ligaments, ligaments mean bone to bone, tendon is muscle to bone. So this is where you actually had that connective tissue continuing on from the muscle belly and actually attaching to the bone. So when this muscle contracts, it allows for the bone to move. Muscle belly is composed of skeletal muscle cells, and we'll get into more detail to those specifics in a moment. Whereas all of those muscle cells are surrounded by differing levels of connective tissue. That connective tissue all comes together to form the tendon. Now you can have a very robust muscle belly, in terms of it being kind of wide or thick, or you can have wide muscle bellies. Very dependent on what the specific function of the muscle is as in to what it's going to look like. The same can be said in terms of tendons. So you can have tendons that are very rope like, as you can see here, in terms of the biceps brachii. So when we think of our biceps brachii, think of flexing. You have actually, because they're referred to as biceps, meaning two heads, so two different tendons attaching to the scapula. You can see this white portion right here, and you can see they're even extending a little bit further, that's going to be the tendon. It's going to be glistening when you're doing a dissection. Whereas you can see the brownish portion, sometimes it'll appear red. That's going to be the muscle belly. So typically what we think of when we're talking about muscles. So you can have those more rope-like tendons or you can have tendons that are very flat and expansive. And one of the main examples of that is your rectus sheath which you have in the abdomen. And you see this shiny portion all over the interior part of the abdomen. This is all an example of a tendon, and specifically when you have it spread out like this, it's referred to as an aponeurosis. So an aponeurosis is basically an amalgamation of tendons from several different types of muscles that kind of spread out over a wider area. And this is an important component of the anterior abdomen, because think of what you don't have in the anterior abdomen. Yes, you don't have bones in this area as in comparison to other areas. So you need this thicker, more protective portion of the tendon. Now one other thing that you can see in terms of a gross dissection of the musculoskeletal system is what is referred to as a neurovascular bundle. And this is going to be wrapped up in its own type of connective tissue. You typically will have one nerve. And that nerve will spread its axons out to the specific skeletal muscle cells. But you won't see that in terms of gross dissection. You typically see kind of the amalgamation of the nerve. So one nerve, one artery, and typically one to two veins. And we refer, when we have the two veins surrounding an artery as a vena comitans. And what will happen is say this is an artery, it's red like any good artery would be. And then on either side, you would have two veins that are going to drain that specific area. So in a gross anatomy when you're doing a dissection, you want to find the muscle belly, the muscle tendon. And you'll typically have at least two, and sometimes multiple tendons associated with a muscle, as well as the main neurovascular bundle for the muscle.
