On 20-08-05, a 33-year-old patient was taken to the emergency department for a bleeding cut on his neck caused by falling over a shop window. In the emergency department an incised trauma was seen in the right antero-lateral region of the neck with a clean dissection involving only the superficial tissues and no apparent damage to the rest of the structures, so the suture was made in planes. On 4-09-06 she attended the emergency department of our hospital for examination of the wound, reporting headache and blurred vision in the right eye (OD). In the ophthalmological examination the uncorrected visual acuity with the OD was 1 and with the left eye (LA) 1. The intraocular pressure was 12 mm Hg in the OD and 13 mm Hg in the LA. Extrinsic ocular motility was normal except for a right palpebral ptosis of 3 mm with good levator function. The pupil of the OD measured 2.0 mm and that of the OI 4.0 mm. The external examination and palpation of the neck, except for the trauma findings, were normal. A cervical CT scan showed a large haematoma with internal growth that was significantly compressing the trachea, so it was decided to perform an intraoperative exploration and evacuation, where a solution of continuity was observed in the external jugular vein that was leaking into deep planes. Five months later, Horner's syndrome had disappeared.