I believe the author explained the accident and the damage in a lot of detail to show how devastating it actually was.
I will return to work in a few days.
Phineas Gage was once a regular foreman of a railroad construction site. One day, an accident sent Phineas' tamping iron through his cheek and forehead, heavily injuring him.
Emphasis on medical history and technology might hint towards a field that Phineas' accident helped advance.
Upon arrival at Cavendish, the town that Phineas resided in, Dr. Harlow, the town physician, was nowhere to be found. Dr. Williams, a physician from the next village, had to temporarily examine Phineas. Phineas' skull was cracked open, causing blood to flow freely. Surprisingly, Phineas was not in any pain this whole time.
Upon Dr. Harlow's arrival, he treated Phineas injury. Luckily, Phineas had suffered an open-brain injury. The hole on his head gave room for his brain to swell up. Somehow, Phineas was able to stay cheerful.
A few days after the accident, the wound took a disgusting turn. Phineas developed a horrible fever and the wound was leaking a horrible liquid. This was a sign of infection. At the time, no one in Cavendish knew that bacteria can cause an infection in an open wound. Medical technology wasn't very advanced back then. A few decades after this accident, an antibiotic would be developed.
Dr. Harlow tried his best to treat the wound by keeping the wound clean. He punctured Phineas' abscesses, drained the pus, and treated his forehead again. Eventually, Phineas started to get better, thanks to Harlow's care and his own constitution. However, Phineas started to ignore the doctor's orders and was diagnosed to have an imbalance of bodily humors, a theory from Ancient Greece that one's health depended on 4 liquids.
Though he was fully recovered, Phineas' personality was drastically changed after the accident. He was rude and irresponsible. Dr. Harlow made sure to note his drastic change in his personality, sparking the interest of others.