My humble opinion, FWIW, knowing the anatomy is important; being able to put the lead where it needs to go, more so. That is in context of what style of firearm and charge is used. I have, at various times, shot deer in the neck and forward thoracic cavity and have yet to lose one after the fact. All of that was with CF rifles. Some were bang-flops, mostly not. Never lost a pig either, and have shot them with 12 & 20 bore buckshot, .30-30s, .257 Bobby and .22 RF, both LR, Shorts and mostly CB shorts. As suggested by Doc R. a CF rifle shot in vicinity of the humerus has been successful, usually with a flop dead result. Buckshot to the same region at reasonable range likewise. The .22 RF requires a CNS shot unless one is adept at tree climbing, particularly if one plinks more than one out of the herd at a time. Best effort in my past was 5 for 5, the two largest in the 200# range. Shots to the cervical vertebra with the CB shorts are effective up to around the 125# size, otherwise I have the patience to wait for them to present the proper aspect for a brain shot. I have shot over 100 hogs with that round and only one required a second shot...........because I did not know the anatomy. Shorts will not penetrate a mature hog's skull reliably with a "behind the ear" shot. Reason? Many layers of bone before one gets to the brain. Hogs have an outer cranium and an inner one as well when viewed from the side. The interior chamber is oriented to the rear of the brain.
End of the day, know the anatomy, your firearm and load, and most of all, have the patience to wait for the proper time for taking the shot. Only fools rush in..........
DD