infraspinatus

noun

in·​fra·​spi·​na·​tus ˌin-frə-spī-ˈnāt-əs 

plural infraspinati -ˈnā-ˌtī 

: a muscle that occupies the chief part of the infraspinous fossa of the scapula, is inserted into the greater tubercle of the humerus, and rotates the arm laterally