 hello everyone welcome back to another session in dentistry and more today's topic in prosodontics is modulus modulus is nothing but a chiasma of facial muscles held together by fibrous tissue which is located lateral and slightly superior to the ankle of mouth so there will be two modulus on the left and right side and why it is important it is important in moving the mouth and also in facial expression and also it has got importance in prosodontics okay so modulus is nothing but a point where the many of the facial muscles getting intersected so it is exactly around 10 to 12 millimeter okay 10 to 12 millimeter lateral to the ankle of mouth it comprises of various muscles such as orbicularis aureus, buccinator, levator ankle aureus, depressor ankle aureus, zygomaticus major, levator lebi superioris, risorius and platysma so the lots of muscles which is intersecting at this point so it is a chiasma of facial muscles chiasma is nothing but a point when two or more structures are intersected okay and the importance of this modulus is we have so many muscle fibers and none of these muscle contain fibers that have more than one bony attachment and they depend on the fixation of the modulus to allow contraction so these have only one bony attachment fibers are one bony attachment and they depend on the fixation of the modulus to allow contraction so it is basically associated with the denger fabrication how we should take care of the denger fabrication with respect to all these muscles action so normally the maxillary teeth supports so the maxilla teeth maxillary teeth supports this modulus in case of the loss of maxillary teeth what happens is it gives a sunken cheek appearance so sunken cheek appearance is because of the maxillary teeth absence and the peculiar modulus will not be supported by any of the teeth and it gives a sunken cheek appearance so why it is important in prosthetics because the denger base must be contoured to permit the modulus to function freely so all these muscle fibers meeting at modulus should be allowed to free movements in order to have a good retention so while preparing the lower denger we need to make the premolar region of the lower denger very thin so that it should not cause any hindrance to the function of modulus otherwise this modulus will lift the denger because of the muscle fibers action so that is the importance of modulus in fabrication it's nothing but a charisma of muscle fibers where many muscle fibers are intersected but its importance is it should not be interfered the denger base should not interfere the function if it interferes the retention will be hampered so maxillary teeth supports this normally if the maxillary teeth is absent it gives rise to a sunken cheek appearance so that's a simple concept of charisma of muscles that is modulus so hope you understood this small topic i'll come within your topic in prosthetics thank you