
In addition to the structures described above, each root contains bronchial vessels, autonomic nerves, lymph nodes, and lymphatic channels. The structures of the lung hilum are enclosed in a sleeve of pleura continuous below with the pulmonary ligament 5. Right pulmonary veins are located at the anterior part of the hilum, followed by right pulmonary arteries, and lobar bronchi 5. The right hilum lies below the arch of the azygous vein, posterior to the superior vena cava and right atrium. Pulmonary veins always lie anteroinferior to the pulmonary artery 5. The left pulmonary artery is anterosuperior to the left main bronchus. The left main bronchus lies at the most posterior aspect of the hilum, with the left superior pulmonary vein located anteriorly and the left inferior pulmonary vein occupying the inferior portion of the hilum. 2 The arrangement of structures at lung hilum acts as a guide in performing such procedures. A thorough knowledge of variations in lung anatomy is of prime significance during surgical procedures such as lobectomy, pneumonectomy, and segmentectomy of lungs. The left hilum lies below the arch of the aorta and anterior to the descending aorta. Bronchial vessels are the posterior-most structures at both hila. A hilar angle is the angle between the vessels at the hilar point, which usually measures 120 ° 5.


A hilar point is a point where the upper lobe vein crosses over the pulmonary artery. The roots of the lung lie between T5 to T7 vertebrae 5. The left and right lung roots are similar but not identical. The lung hila or roots are found on the medial aspect of each lung.
