A 46-year-old man underwent a left shoulder surgery in the beach chair position with general anaesthesia and oro-tracheal intubation preceded by a left interscalenic block. Patient's head was attached to the headrest in a position of soft extension and moderate right rotation with adhesive tape surrounding his forehead and mandible. Surgery was marked by repeated vertical tractions on the left arm and by blood resorption of the arthroscopy's irrigation fluid, including epinephrine, which translated in a heart rate and arterial blood pressure rise. Upon waking the patient had severe headaches, left Horner's sign, left facial paresis and a left lingual paralysis. MRI and CT scan did not show any carotid dissection or parapharyngeal lesion. Electromyogram and neurological examination confirmed a VII and XII cranial nerve peripheral lesion, which took several months to regress. An ischaemic complication was suspected although the most probable cause of the patient's symptoms was subsequent to an Eagle's syndrome neurapraxia related to a long styloid process.