One of four deaths subsequent to trauma is due to thoracic trauma with 10% mortality. In 85% of cases treatment of these injuries is chest drainage. Some cases will need a surgery as massive hemothorax with hemodynamic instability. Operative decision depends of the patient's physioloc status and/or the volume of the blood obtained through chest drain. On of the challenges of the trauma surgeon is chosen the incision. Wrong incisions delay the treatment and the hemorrhage continuous and you can lose patient. To avoid aggravating if clinical conditions permit any image diagnosis may be done, simple as an X-ray made in emergency room. So when and where do you choose the incision? Discussing a clincal case of massive hemothorax and the treatment. This case of a massive hemothorax due traumatic diaphragmatic hernia with spleen bleeding in chest. Answers of simples questions and simple exam are helpful to choose adequate incision in this case. This case shows that choice of right incision is one of the hallmarked oftreatment chest injury; it still is a challenge to surgeon and depends: physiologic status, blood volume from chest tube, mechanism of trauma, and image exam at emergency room X-ray.