Need help on a ER question question: 9th grade level.?

I believe that this is a musculoskeletal problem and that since it's compromising his breathing, it will be potentially life threatening. I can present a list of what he might have but I suspect he has an underlying problem with his muscles. Life threatening problems would include inability to breathe enough to meet his body's demand. When evaluating this patient, there would be very specific questions about his gait abnormality which could help confirm a diagnosis for him, but I sspect that he's suffering for a congenital (something he's born with) musculoskeletal problem that is systemic.