Pharyngeal Muscles

00:01 The next group of muscles we're gonna look at are the pharyngeal muscles.

00:07 So here's a sagittal view where we can look at the layers of the pharynx.

00:12 Now the layer that lines the cavity of the pharynx, it's going to be the mucous membrane.

00:18 And it's mostly going to be composed of stratified squamous epithelium.

00:24 Further up in the nasal pharynx, we're gonna have ciliated columnar epithelium, very similar to the rest of the nasal cavity.

00:35 Now, if we go a little bit deeper to the mucosa, we're going to have the pharyngeal aponeurosis, aponeurosis is just a term for a wide flat sheet of connective tissue.

00:44 We also call this the pharyngobasilar fascia.

00:48 That's gonna have a superior portion and an inferior portion.

00:53 Then we're going to have a muscular coat.

00:57 Then a buccopharyngeal fascia.

01:01 And because of all of these layers, we're going to create different spaces.

01:06 So in order to visualize these spaces, we're going to look at a cross section in a sort of transverse view here.

01:13 The first thing we're going to see is this space beyond the fascia here called the retropharyngeal space.

01:21 And again, here we see the buccopharyngeal fascia.

01:25 And then we have the prevertebral fascia beyond that retropharyngeal space.

01:33 Lateral to this, we have the parapharyngeal space.

01:40 Let's look at the muscles that make up the pharynx, namely the constrictor muscles.

01:49 Here we can see a little bit of that pharyngobasilar fascia.

01:54 And then we have the superior constrictor, middle constrictor and inferior constrictor muscles.

02:01 The fibers on both sides meet in the midline to form a little bit of a scene called the pharyngeal raphe.

02:09 Let's start with the superior constrictor and its attachments.

02:14 Well, it's going to attach to that median pharyngeal raphe, posteriorly.

02:19 And then it's going to attach to the side of the tongue.

02:22 And that portion of the mandible, we call the mylohyoid line.

02:30 It's also going to attach to the pterygomandibular raphe that's part of the buccopharyngeal fascia.

02:39 It's all also going to attach to a little hook thing called the pterygoid hamulus that's on the medial pterygoid plate.

02:48 The next muscle is going to be the middle constrictor.

02:52 And it will again attach posteriorly to the median pharyngeal raphe.

02:57 But it's also going to attach to a ligament between the styloid process and the hyoid bone called the stylohyoid ligament.

03:06 It's also going to attach to the horn or cornua of the hyoid bone.

03:12 The inferior constrictor is again going to attach to the median pharyngeal raphe as they all do, and then anteriorly, it's going to attach to part of the fibroid cartilage of the larynx.

03:24 And the other cartilage of the larynx that goes all the way around circumferentially called the cricoid cartilage.

03:31 So the portion of the inferior constrictor that attaches to the thyroid cartilage called the thyropharyngeus and the portion attaching to the cricoid cartilage, we call the cricopharyngeus.

03:44 We also have some what we call potential spaces between the external pharyngeal muscles or pharyngeal constrictor muscles.

03:53 There are potential spaces because there's not actually a lot of space between them, but there can be in cases of pathology.

04:02 So here we have a couple of spaces between the base of the skull and the superior constrictor such as the sinus of morgagni, a bit of an eponym.

04:12 And here we also see where the pharyngotympanic tube would be.

04:17 We also have another potential space between the superior and middle constrictor.

04:23 And we can actually see some things in here such as the glossopharyngeal nerve and the stylopharyngeus muscle.

04:33 The next space between the middle and inferior constrictor muscles, we can see a little bit of the internal laryngeal nerve and the superior laryngeal vessels that are covered in the neck portion.

04:47 Then the fourth space here is beyond the inferior constrictor and this is where we can see the inferior laryngeal vessels entering along with the recurrent laryngeal nerve coming up from below.

05:05 Here we have a posterior view, where we see the components of the inferior constrictor muscle, the superior thyropharyngeus and the inferior cricopharyngeus.

05:16 And we see that there's this little bit of connective tissue here called Killian's dehiscence.

05:23 And this is the potential site for a weakening and expansion, when we have weakening and expansion, we call that a diverticulum.

05:31 And in this location if it were to become weak and expand outward, this would be called Zenker diverticulum.

05:40 Let's look at the superior constrictor again, the middle and inferior.

05:47 We again see the relationship to the Eustachian tube, and there's a very small muscle in this area that connects to that Eustachian tube, called the salpingopharyngeus.

05:58 Now pharyngeus tells us that we're in the area of the pharynx, but salpingo is another word for tube that tells us that it's actually connecting to the opening of the eustachian tube.

06:09 Here we see the styloid process and a muscle running between the styloid in the pharynx called stylopharyngeus.

06:18 We also have the aptly named palatopharyngeus as it's attaching to soft palate.