成人食管总长25～30厘米,因人而略有差异。临床及X线上可将食管分为颈段、胸段和腹段三部分。胸段食管最长,由于临床医疗工作和科研方面需要又将它分为三段,即主动脉弓水平以上为胸上段,下肺静脉以下为胸下段,两者之间为胸中段①。然而,下肺静脉在胸部正位平片上,尤其是左下肺静脉被心脏遮挡,无法确切定位;在食管左、右前斜位片上也无法精确确定其位置, Adult esophageal length 25 to 30 cm, slightly different because of people. The esophagus can be divided into three parts: cervical, thoracic and abdominal. The thoracic esophagus is the longest, and it is divided into three segments because of clinical medical work and scientific research needs. That is, the aortic arch is above the level of the upper thoracic segment, and the lower pulmonary vein is below the thoracic segment, with the middle thoracic segment between the two. However, the inferior pulmonary veins are located on the plain radiographs of the chest, especially the left lower pulmonary veins, which cannot be accurately positioned; nor can they be accurately located on the left and right anterior oblique sheets of the esophagus.