Occipital Bone

00:02 Here's an inferior view so we can look at the occipital bone.

00:06 And the occipital bone has a basilar part anteriorly.

00:11 Then lateral parts.

00:12 And then most posteriorly we have the squamous or flat parts.

00:17 And this is where we find the foramen magnum.

00:20 The opening through which the brainstem becomes the spinal cord.

00:26 If we look internally.

00:28 We see there's this flat portion of the basilar part called the clivus.

00:33 And there's a groove for another sinus here called the inferior petrosal sinus.

00:38 And we flip around to the external surface.

00:41 We see a tubercle for some pharyngeal muscles to attach called the pharyngeal tubercle.

00:48 There's also a little groove here for the sigmoid sinus.

00:53 And externally we have bumps for the attachment to the atlas called the occipital condyles.

00:59 Again this is the part that's going to rest on the vertebral column.

01:03 We also have a condylar canal.

01:06 And a hypoglossal canal for structures to pass through.

01:12 Internally, we have this cruciform eminence where these vertically and horizontally oriented bumps meet.

01:22 And this is we're going to have little fossa for the cerebrum on either side left or right.

01:28 We also more inferiorly of fossa for the cerebellum, which is the smaller portion of the brain.

01:36 And again, we have groups for dural venous sinuses in this case we have the superior sagittal sinus here.

01:41 And running transversely the group for the transverse sinuses.

01:47 On the internal surface where these two groups meet is a bump called the internal occipital protuberance.

01:55 And then the crest that runs from that is called the internal occipital crest.

02:02 We swim around to the external surface.

02:04 We have the corresponding external occipital protuberance.

02:09 So that's a bumped you can feel on the outer surface of the occipital bone.

02:14 And similarly, running from that is the external occipital crest.

02:19 The flat part above that is the occipital plane.

02:23 And then running laterally from the midline we have the inferior nuclear line.

02:27 Which is this attachment point for a lot of muscles.

02:31 We also have superior nuclear line.

02:32 And supreme nuclear line doing similar things.