Brief Answer:
It means bony thorax,it includes ribs,vertebra.

Detailed Answer:
Hello XXXXX
Thanks for writing to XXXXXXX

Osseous structures means bony structures and in thorax it includes ribs,vertebra,clavicle.
It is normal in your case. There is no abnormality in bones.

There is some problem in perfusion study and in your case it is due to ischemic( decreased blood supply to part of heart)insult.
Yes, you can definitely live long and can also lead normal life with this abnormality provided you have to take proper precautions in daily activities.
There is problem in blood supply(moderate size) in mid to septal wall of heart and it is nonreversible. However there is no problem in heart contraction, no problem in heart wall movement and ejection fraction is also satisfactory. With regular medicines you can prevent further damage to heart .

You have to take medicines regularly prescribed by cardiologist and follow their instructions. You also need periodic health checkup and should fully aware of warning signs when to contact your doctor.

Hope I have answered your query.
Get well soon.
Further queries are most welcome.

Take Care
Dr.Indu XXXXXXX

---