facial muscle: any of the skeletal muscles of the face
skeletal muscle: a muscle that is connected at either or both ends to a bone and so move parts of the skeleton; a muscle that is characterized by transverse stripes
nucleoside reverse transcriptase inhibitor: an antiviral drug used against HIV; is incorporated into the DNA of the virus and stops the building process; results in incomplete DNA that cannot create a new virus; often used in combination with other drugs