scalenus: any of four pairs of muscles extending from the cervical vertebrae to the second rib; involved in moving the neck and in breathing
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
halon: a compound in which the hydrogen atoms of a hydrocarbon have been replaced by bromine and other halogen atoms; very stable; used in fire extinguishers although it is thought to release bromine that depletes the ozone layer