Phrenic nerve palsy has many causes, and can be caused by lesions anywhere along its course, as it travels from the neck to pierce the diaphragm. Нe epidemiology will therefore match that of the underlying etiology [1]. Most of the cases are idiopathic or even thought to be post viral. Common causes include: tumors like bronchogenic carcinoma or neuroblastoma, trauma like post thoracic or neck surgeries or penetrating injuries, neuromuscular diseases, inflDmmDtion direct compression from aortic aneurysm or cervical osteophytes, toxins like some spider or lizard toxins, alcoholic neuropathy, or endocrinal causes like hypothyroidism or diabetes mellitus (diabetic autonomic neuropathy) which enhances and exaggerates the eوٴect of the other factors [2-4]