which is present at birth. The VI cranial nerve, which controls lateral eye movement, is also affected, so people with Moebius syndrome cannot form facial expression or move their eyes from side to side. Moebius syndrome is extremely rare, and its cause or causes are not known. Facial piercings, namely eyebrow piercings or tongue piercings, can in very rare cases cause damage to the facial nerve. Diagnosis A medical history and physical examination, including a neurological examination, are needed for diagnosis. The first step is to observe what parts of the face do not move normally when the person tries to smile, blink, or raise the eyebrows. If the forehead wrinkles normally, a diagnosis of central facial palsy is made, and the person should be evaluated for stroke. Otherwise, the diagnosis is peripheral facial palsy, and its cause needs to be identified, if possible. Ramsey Hunt's syndrome causes pain and small blisters in the ear on the same side as the palsy. Otitis media, trauma, or post-surgical complications may alternatively become apparent from history and physical examination. If there is a history of trauma, or a tumour is suspected, a CT scan or MRI may be used to clarify its impact. Blood tests or x-rays may be ordered depending on suspected causes. The likelihood that the facial palsy is caused by Lyme disease should be estimated, based on recent history of outdoor activities in likely tick habitats during warmer months, recent history of rash or symptoms such as headache and fever, and whether the palsy affects both sides of the face (much more common in Lyme than in Bell's palsy). If that likelihood is more than negligible, a serological test for Lyme disease should be performed. If the test is positive, the diagnosis is Lyme disease. If no cause is found, the diagnosis is Bell's Palsy. Classification Facial nerve paralysis may be divided into supranuclear and infranuclear lesions. In a clinical setting, other commonly used classifications include: intra-cranial and extra-cranial; acute, subacute and chronic duration. Supranuclear and nuclear lesions Central facial palsy can be caused by a lacunar infarct affecting fibers in the internal capsule going to the nucleus. The facial nucleus itself can be affected by infarcts of the pontine arteries. These are corticobulbar fibers travelling in internal capsule. Infranuclear lesions Infranuclear lesions refer to the majority of causes of facial palsy. Treatment If an underlying cause has been