Sphenoid Bone

00:01 The sphenoid bone is very complicated and has lots of different parts.

00:06 We'll start with the centrally located body.

00:10 To which we have small projections called the lesser wings.

00:15 And then larger projections called the greater wings.

00:19 Running more inferiorly are these processes called the pterygoid processes.

00:26 If we look at the body, especially its anterior surface, we can see a little sphenoid crest in the midline.

00:33 And apertures for the sphenoid sinus.

00:36 The spheroid sinus being one of the pair of nasal sinuses that exists within the sphenoid bone.

00:43 We also see the inferior surface and lateral surfaces here.

00:50 And if we swing around, we see the posterior surface.

00:54 And this is going to interact with the occipital bone.

00:59 Here we see the superior surface.

01:02 And it has structures such as the jugum sphenoidale.

01:06 And part of the clivus, the smooth part that's going towards the occipital bone.

01:12 And then there's a little groove called the chiasmatic groove.

01:16 Where we have the optic chiasm.

01:18 And this is where the optic nerves sort of crossover before becoming the optic tracts.

01:25 And this region is known as the sella turcica, because of its resemblance to a Turkish horse saddle.

01:32 And it has a little depression called the tuberculum sellae.

01:37 And the dorsum sellae.

01:39 And together they're going to form this hypophysial fossa.

01:43 Which is going to be the space in which the pituitary gland sits.

01:50 Now we see the larger projections the greater wings sticking out laterally.

01:56 And here we have the various surfaces.

02:00 And openings of the greater wing of the sphenoid bone.

02:04 First we see the foramen rotundum.

02:08 And the more oval shaped foramen ovale.

02:12 We also have a smaller one called the foramen spinosum.

02:19 Here we see laterally the temporal portion or the temporal surface of the sphenoid bone.

02:27 And in here we see the orbital surface from an anterior point of view.

02:33 And from this point of view, we can see another opening and this is the optic canal.

02:38 Which is the opening for the optic nerves.

02:41 Between the lesser and greater wings is a much larger opening called the superior orbital fissure.

02:46 Through which multiple cranial nerves are going to pass.

02:53 Hanging down inferiorly from the sphenoid bone are the pterygoid processes or plates.

03:01 We have a medial plate.

03:03 And a lateral plate.

03:05 And in between is the pterygoid fossa.