Sentence:  Microscopic studies of the gastrocnemius , pectoralis major , transversus abdominis , biceps brachii , and diaphragm showed atrophy as well as varying degrees of injury ranging from swelling and vacuolization to focal <WSD>necrosis</WSD> of the muscle fibers . 
Meaning of the word marked with <WSD> tags:  the localized death of living cells (as from infection or the interruption of blood supply)