When Tori Westerhoff was in sixth grade at the Wellesley Middle School, she fell off a rock climbing wall and sustained many internal injuries, as well as severe damage to her right knee. In the four years since the accident, Westerhoof, now a sophomore at Wellesley High School, has undergone four different knee surgeries, where doctors used pins and wires, as well as a tendon harvested from her hamstring, to hold the patella in place.

Still, despite the surgeries, months of bed rest and four years (and counting) of physical therapy, Westerhoff’s knee is far from normal. Most of the cartilage is gone, she said, which is why it’s so painful. The former multisport athlete — “I played everything!” she said. “Softball, basketball, skiing, lacrosse, soccer, but I was really good at… racing sailboats.” — can no longer run or climb stairs, let alone play sports. But, while she acknowledges a sense of loss over certain things in particular, such as sailing and performing in the Wheelock Family Theater, Westerhoff said, “I usually don’t dwell on it because I’m trying to really focus on what I CAN do, not what I can’t.” Instead, she decided to focus her energy on art, writing and music. She paints, draws and plays trombone in the Boston Youth Symphony Orchestra, and two New England Conservatory youth orchestras, one of which will take her to Greece this summer.

She has also just self-published her first book.

“Humpty Dumpty Fell off a Rock Wall,” is a children’s book, based off the well-known nursery rhyme, and Westerhoff’s own experience. She conceived of the idea for the book when she was 14, she said, two years after her accident. “There were no inspirational books like ‘Humpty’ available when I had my accident,” she said. “So I wanted to write something for the young children that would give them hope … I’m at Children’s Hospital frequently and see so many kids who really need encouragement, such as kids using walkers, toddlers in braces and permanent crutches. They need to know that there’s a world full of possibilities out there that don’t necessarily require physical dexterity, such as art, writing and music.”

Like Westerhoff, Humpty takes a fall off a rock wall on the very first page of the book. “All of the hospital’s women and men, worked hard to make Humpty better again. Soon Humpty could walk like before. But climb, jump and run he could do no more,” the book starts out. “‘Humpty’ recognizes the sadness and loss a child feels when he or she is physically limited,” Westerhoff said. “However, most of the book focuses on Humpty’s positive, can-do attitude. He finds his place in the world and triumphs in the end.”

Brought to life in the colorful illustrations of Massachusetts College of Art graduate Audrey Ficociello, “Humpty” soon discovers he loves many of the same activities Westerhoff found to replace sports. “Humpty painted landscapes with flair, under the sun in the fresh autumn air … Humpty also spent lots of time playing his horn. Friends liked his sound and new music was born.”

Westerhoff chose to use Humpty as the main character for her book because “as a young child I liked the musical quality of rhymes and thought I could get my point across using my own rhyme as a twist on the standard nursery rhyme we all grew up with,” she said.

The 16-year-old credits many people with helping her get through the time after the accident, including her family, her medical team at Children’s Hospital, and several particularly wonderful middle school teachers, Anne Greene, Henry Platt and Bill Atherton. Greene, she said “was like a second mother to me when my accident occurred. Academically, she developed a plan for my mother to teach me at home for a term and as I gradually returned to school, made certain that I didn’t fall behind. I couldn’t even carry my backpack; she helped me with everything.”

When Westerhoff returned to the middle school, she said she almost dropped out of band because she couldn’t carry her trombone. “Mr. Platt insisted on carrying the horn and walking me safely back to class after every rehearsal. He would always have something positive to say that encouraged me personally and musically, and for this I will always be grateful,” she said.

And Atherton, her eighth-grade science teacher, she said, “is one of the smartest people I’ve met. His genuine love of science and teaching is contagious … it was this spirit that fueled my interest in science. He took the time to research science camps for me, somehow knowing I would need a replacement for the sailing camp I had to give up … He’s the guy they really made that coffee mug for: World’s Greatest Teacher.”

All of the proceeds from “Humpty” will go to the Extraordinary Needs Fund at Children’s Hospital, which provides families who come from out of state, and might not otherwise be able to afford to stay in Boston, with the money to stay in the city while their child is being treated. Westerhoff has also donated copies of the book to 38 children’s hospitals nationwide, with the goal of eventually having it available in at least one children’s physical therapy hospital or facility in each of the 50 states. “I feel it is important that it be available to those who need it most,” she said. “I want this message to empower all children, with or without physical challenges.”

“Humpty Dumpty Fell off a Rock Wall,” is available at the Wellesley Free Library. To order a copy of the book, for $6, e-mail on_a_high_note@comcast.net.