In the early 1900s, there weren’t a lot of regulations in place to protect the safety of U.S industrial workers, and terminal devices for upper-limb prostheses were somewhat limited. This is the cultural landscape that D.W. Dorrance found himself in when he underwent a traumatic amputation of his arm as a result of a workplace accident in his job as a lumber supervisor. Seeking a better solution for his own needs, he invented the split hook in 1912 and founded the company that is today known as Hosmer, Campbell, California. The O&P EDGE congratulates Hosmer on 100 years in business. The following images provide a glimpse into the evolution of this century-old company.