Sentence:  In February , 1959 , during the second admission to The New York Hospital , a biopsy specimen of the <WSD>left</WSD> gastrocnemius showed striking increase in the sarcolemmal sheath nuclei and shrunken muscle fibers in several sections . 
Meaning of the word marked with <WSD> tags:  being or located on or directed toward the side of the body to the west when facing north