The motor point is usually located at the center of the muscle mass where the motor nerve enters the muscle.
Definition A carcinogen is defined as something that can directly cause cancer. This can be a chemical substance, a virus, or even the medications and radiation we use to treat cancer. While many cancers are caused by a carcinogen or combination of carcinogens, the tendency to develop cancer may also be inherited as part of our genome.
Carcinogen: A substance or agent that causes cancer. Related terms include the adjective  carcinogenic  and the nouns carcinogenesis and carcinogenicity.. One of the best-known carcinogens is ionizing radiation.