in this video we'll see about expanding V principle or endosb principle and in those counterpart principle these are the two concepts which were put forward by Enloe and these topics comes under growth and development in Orthodontics so first thing about en loss B principle most of the bones in the cranial and facial region the craniofacial bones mostly follow a V shape configuration and according to Enloe they said that there will be bone deposition in the inner aspect of the way and there will be bone resorption in the outer aspect so the inner aspect or the inner surface of the bone we call it as industrial surface and outer surface we call it as periosteal services and it is said that the endoster surface is lined by Osteo blast cells and periodical surfaces lined by osteoclasses the bone dissolving cells and thus phone deposition occurs on the inner aspect and Bone resorption occurs on the outer aspect this statement goes further brewed in an implant study where implants were placed on both periosteal and endosterone surfaces and when they did it was proven that there was one resorption occurring in the periosteal surface and there was Detachment of the implant in the periodical surface and whereas in the industrial surface the implant did not get completely detached due to the expansion and Bone deposition occurring on the industrial surface so as this bone deposition and resorption occurs what happens is the first position from here the bond it will continue the bond of position and this option will continue and finally the bone will move from this position there is a narrow position end of the V to a wider it something narrow end it will move to a wider end with growth and expansion this is a whole concept of end loss weight principle and is the most accepted principle whereas endless counterpart principle is one which is not accepted which we will say later and we have examples which will show endless wave principle the best example is palette palette is one of the best examples showing endless wave principle so this is a rough diagram which I have drawn first diagram shows that it's a section of an angle child in angular child you can see that palette and nasal floor is close to the infraorbital rib but as the development happens there will be descending down of the palette how it is happening is so considering the palette is a V shape there will be bone deposition occurring on the inner aspect so the inner aspect this side is the palatal side and burn this option on the outer aspect the outer aspect it is towards the nasal surface so that is a nasal cell so as this happens there will be from this position it will finally move down it will be descending down that's how parallel growth occurs following the expanding way principle next example is mandible so in mandible when you see in this view that is my top view we can see the growth of the Corn day the growth of the body of the mandible and ramus of the mandible itself is called cause the expansion of teeth mandible in a posterior and lateral Direction so from this position it will be expanding and as a wider position by expansion and growth this shows expanding the principle in mandible and this is the diagram which we have already seen in drift and displacement in Orthodontics so this is something which you have seen in primary displacement in in our previous videos so in primary displacement we saw azikondyle grows upward and backwards to maintain contact with the forza there will be displacement of the mandible in a downward Direction so this is the one which is seen here with moons following more deposition on the inner aspect and resorption on the outer aspect and condyle growing in upward and backward Direction the mandal will be displaced in a downward Direction and growth will be taking place so this is the example of expanding the principle in palette and mandible it's nothing but wound up position and resorption occurring in a continuous manner the position in the inner aspect and absorption in the outer aspect finally there will be growth and movement of the bone from a from the narrow end of the V towards the wider there will be expansion and growth of the mode that is analogs reference next coming to and loss counterpart principle so what this principle says is growth of Any Given facial or cranial bone will relate specifically to the other structural and geometric counterparts related to it so what this says is growth of one bone in cranial official region will influence growth of another the growth of its counterpart and why this happens is to maintain a balance in growth and for a functional equilibrium to be established but this counterpart principle is not accepted and we have some examples of bone at its counterpart the examples are nasal maxillary complex and anterior cranial fossa width of ramus then maxillary and mandibular arches last maxillary tuberosity and lingual tuberosity so this is all about and loss V principle analogous counterpart principle thank you see you again in another video