The human face contributes greatly to our identity and capacity for non-verbal communication. The muscles that express our internal state of being are called muscles of facial expression. They share innervation (facial n.), a large portion of blood supply (facial a.). Sensation on the face is the job of the trigeminal n. This, coupled with the presence of a large salivary gland, the parotid, make the face a useful diagnostic tool for any clinician.