Hinges are usually connected to the base of the laptop as well as the LCD back cover. They also hold the screen in place through two brackets. And also hold on to the side of the screen on some models.
However, Ultra book or ultra thin laptops have different kind of hinges that don't hold the screen. Instead, they hold only the LCD back cover, and the LCD back cover holds the screen. This is possible as these laptops have ultra thin screens that don't weight as much as the older models.
Why Replacing Laptop Hinges is Important
Replacing the hinges on a laptop is not very straight forward. It will involve stripping the whole laptop apart most of the time. As hinges connect to the base and LCD back cover, to get to the hinges screws on most laptop requires removing the motherboard and screen. And to screw on the new hinges. Difficulty is around 7/10 on most laptops.
Not replacing the hinges can cause more damage to the laptop. Such as cracking the screens and damaging the LCD Bezel or palm rest is very possible . We recommend to have your laptop checked by a technician if you suspect hinges are not stable or strong enough.