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 <WSD>focal</WSD> necrosis of the muscle fibers . 
Meaning of the word marked with <WSD> tags:  having or localized centrally at a focus