Paranasal Sinuses – Nasal Cavity

00:01 The first, we have the pair of frontal sinuses, these are pretty symmetrical and how they're artistically illustrated, but they may be asymmetrical, the right one might be larger, than the left one and vice versa.

00:17 Located just below the frontal sinuses, are the ethmoidal air cells of the ethmoid bone.

00:25 And then, inferiorly located are the large maxillary sinuses and the last sinus is the sphenoid sinus and that is shown in through here, as we start to look at communications of the sinuses, with the nasal cavity.

00:45 The sphenoidal sinus, is also paired and it is usually unequal in size, because the septum does not evenly divide the sphenodial sinuses into equal paths.

00:58 But here is the opening of the sphenoidal sinus, into the nasal cavity, this is a section through, where the superior nasal concha, is projecting towards us, so, it's right above that particular area.

01:18 We have between the superior nasal concha and the middle nasal concha, in the superior meatus area, we have the openings of the posterior ethmoidal cells.

01:36 Just inferior to the middle nasal concha, in the middle meatus area, are the openings of the middle ethmoidal cells.

01:48 And then, this semilunar feature right in through here in the middle meatus, is the floor of the hiatus semilunaris and the opening that is in here, is the opening from the maxillary sinus.

02:04 And this is the anterior semilunar extension of the hiatus in my lunaris, from where we were, just a moment ago.

02:14 And then, also in this same general area the middle meatus, just inferior to the middle nasal concha, we have another opening, this is the infundibulum, opening of the frontal nasal duct, that drains the frontal sinus and the anterior ethmoidal cells.

02:36 Located in the inferior meatus, which is located right below the inferior nasal concha, is the opening of the nasal lacrimal duct.

02:46 So, lacrimal secretions begin in the superior lateral aspect of the eye and then, travel toward the inferior medial aspect of the eye and then, are collected by the nasal lacrimal duct and then, tears enter the nasal cavity in the region of the inferior meatus.