Not only the injection, but also the immersion. The injection has the highest efficiency due to the mechanical penetration of the tissues.
Brines as a solution of NaCl in H2O are common, but there are several salts and other substances that are combined against oxidation and against the development of microorganisms.
There is a preservation component by keeping the meat in sodium chloride solution. There is also a ripening stage of transformation of meat tissues into easily digestible material,edible one