welcome back everyone this is dr. O and we're going to talk through the
pterygomasseteric sling and this is also known as the masticatory sling so we'll talk
about which of the muscles which of the muscles of mastication make up this sling
so we're going to start with our visual here first we'll see that the first muscle is that
masseter muscle found more laterally and then as we look from inferior here the more medial
muscle we're talking about is the medial pterygoid muscle so the two muscles of the
masticatory sling are the masseter and the medial pterygoid muscle well remember that
they have a similar attachment on the mandible at the angle and the ramus and
they mirror one another in kind of the fiber direction so many of their actions are shared
let's look at these attachment points so the masseter and the medial pterygoid share that
inferior attachment point along the angle and the ramus of the mandible the masseter
is found on the lateral surface and the medial pterygoid on the medial surface the
masseter superior attachment is up here on the zygomatic arch the medial pterygoid muscle
has its attachments on the medial surface here of the lateral pterygoid plate as well as down
here on the maxillary tuberosity and parts of the Palatine bone so the way that these
muscles are oriented in parallel with one another they allow for many of the same actions and they
form this sling around the mandible so you can imagine that kind of holding that up right there
now all during this view let's also consider some of the fascial spaces in the region so
between the masseter and the ramus of the mandible we find the masseteric or the sub
masseteric space and then between the ramus of the mandible and the medial pterygoid
muscle we find the tear go mandibular space and you'll remember from dr. Fox's lecture
back in the first part of the course that these communicate with the lateral pharyngeal
space and that communicates later than with the retro pharyngeal space so these are connections
between these places right around the muscles of mastication and deeper into the pharynx and
retropharyngeal space and then you'll remember that that can connect down to
the mediastinum so let's review what we learned about the muscles of mastication and I want you
to write out which actions of the TMJ are performed by the muscles in the masticatory or pterygomasseteric
sling so pause so you have a chance to write some down and then let's talk about them
when you're ready what are the actions that both of these muscles perform so
one of these actions as we see the shortening of the muscle especially
here with masseter but also here with medial pterygoid and that is the action of elevation
the next that we see and this can be dependent on the fibers acting but as we see kind of pulling
forward here and pulling forward there that action is protraction or protrusion
and both are interchangeable can be used either way and we'll remember
also that the masseter muscle some of its fibers will oppose that action and do some
retraction but the shared actions between the masseter and the medial
pterygoid muscle are elevation and protein thank you so much for your attention this
is all for this video and we'll see you in the next one have a great rest of your day