Trunk Struts
It’s not at all unusual during the lifetime of a vehicle to have the trunk strut quit, and have to resort to propping the trunk open with sticks and other objects.
It is also not unusual to accidentally knock that support out or to have someone else do it for you, while getting things in and out of the trunk, resulting in a good whack on the head or whatever body part managed to be in the way.
Considering how affordable a replacement is and how easy it is to swap out the old strut for a spiffy new one that will do the job, that is a silly sort of injury to endure and the giggling witnesses to such an injury are surely something you could easily do without.
When shopping for your replacement part, be sure to carefully match the aftermarket version with your original and make sure that it is a quality part you are buying. That way, you can expect that when you open your trunk, the lid will remain in the desired position until you close it for a good long time to come.