 So today's topic is cartilaginous theory, so in theories of growth we have covered genetic theory and spiritual theory, so where the growth and the development, the theory emphasizing on genetics and the sutures, this particular theory which is concentrating on cartilages. So this was given by Scott, it's also known as Scott's Hypothesis, so the theory emphasizing on the role of cartilage in growth and development of head and face region, so that is the cartilaginous part act as a primary growth centers in maxilla and mandible, so in maxilla the cartilaginous part is nasal septum or nasal septal cartilage and in mandible it is quantilar cartilage, so these cartilages act as intrinsic factors, on cartilaginous there is intrinsic factors in growth and development, so these factors are present in cartilage on periosteum, whereas sutures act as secondary, because they just respond to the response due to seeing controsis proliferation and local environmental factors, but in sutural theory they were highlighting the sutures, but this is opposite, so intrinsic growth controlling factors are present in cartilage and periosteum, whereas sutures are secondary and dependent on the extra sutural influences, so we need to recognize the skull as a primary center of growth with nasal septum being the major contribution in the maxillary growth, but whereas the mandible we can say that the contiles, the contila cartilage, the evidences are the epiphyseal plate when transplanted to another site the growth continues, so it was not there in the sutural theory, when sutures were transplanted the growth did not occur, but the epiphyseal plate when transplanted the growth continues and nasal septal cartilage also when it is transplanted it also shows growth and when it is removed the nasal septal cartilage is removed, it was found that there is a mid facial deformity, so thereby they can emphasizing on the potential of cartilage in growth and development of naso maxillary complex and mandible, but the problem with this mantibular contila cartilage it did not develop into or it did not create a new growth at a different site or the contila cartilage could not continue the growth at a different site when transplanted, so it is actually a growth center not a site of growth, so that was one of the shortcoming but still mandibular contile is act as a growth site, so this is basically the theory is stressing upon the cartilage, so every theory has one key point this is genetics this is future and this is cartilage, so the two key cartilage in the head or the face is maxillary nasal septal cartilage and in mandible it is contila cartilage and this cartilage creates or it produces the intrinsic factors for the growth and causes the growth and development of naso maxillary complex and mandible, so that is how the cartilage in theory explains the growth and development of head and face region, so now let us move on to the functional matrix theory, thank you. The nasal septal cartilage which forwardly and downwardly displaces naso maxillary complexes as a part of the growth, so when growth happens the naso maxillary complex, so naso maxillary complex the same complex we have seen in future theory but the futures are creating the potential for growth but here it is a cartilage that is a nasal septal cartilage which creates a potential and moves the naso maxillary complex forward and downward at the same place the contils contila cartilage it need to be considered as a long bone with cartilage is present at the both ends, so it act as a growth centers and it produces growth, so the growth of mandible is explained by the contila cartilage, so all the cartilages throughout the skull are primary centers of growth and the growth of maxilla is attributed to the growth of nasal septal cartilage which causing the forward and downward growth of naso maxillary complex and nasal septal cartilage is a pacemaker of a growth of naso maxillary complex and as I told mandible it is like a diaphysis of long bone bent with epiphyzyl cartilage at both ends, so we know that the shape of mandible, so if we bend it it looks like a diaphysis of a long bone with epiphyzyl cartilage at both the ends, so that's how scot explained the growth of maxilla and mandible.