English to Japanese Tech/Engineering Medical: Cardiology Raw Material Data

The intramuscular (IM) administration of epinephrine (epinephrine autoinjectors, eg, the EpiPen™) in the anterolateral aspect of the middle third of the thigh provides the highest peak blood levels.

anterolateralとmiddle third の意味は分かるのですが、どうつなげていいか分かりません。よろしくお願いします。