Internal Oblique – Anterolateral Abdominal Wall

00:01 Let's move on and deep to this muscle, deep to external oblique, we find internal oblique.

00:08 So here on the diagram, we can see external oblique here has been cut away, and we're left with this muscle that's radiating underneath.

00:16 So here we have some details.

00:18 You can notice that the fibers of internal oblique run in the opposite direction to that of external oblique, and this is really important.

00:28 So external oblique is running down in this direction, like you're putting your hands in your pockets, external oblique.

00:35 We've got some details of its origin and its insertion here.

00:40 It originates from the iliac crest from the pelvic bone and also an important piece of fascia most posteriorly called thoracolumbar fascia.

00:50 It also attaches to the inguinal ligament, and we'll see that in more detail when we look at the inguinal canal.

00:57 As it's running up in this direction, we can see an insert into ribs 10 and 12.

01:02 And also lies some aponeurosis, which we'll talk about the internal oblique muscles attached to the linea alba.

01:11 Nerve supply again is similar to external oblique and rectus abdominis.

01:15 And it's the thoraco-abdominal nerves coming from the spinal cord T6 through to T12.

01:22 Internal oblique does the same function as external oblique, it helps to flex and rotate the trunk enabling us to move and importantly like I mentioned before, it helps to compress the internal viscera, increase the pressure and support the abdominal cavity.

01:38 So we've got internal oblique that lies deep to external oblique.