THORAX ABDOMEN AND PELVIS

Detailed explanation-1: -The hilum is surrounded by pleura, which extends inferiorly and forms a pulmonary ligament.

Detailed explanation-2: -A pleura is a serous membrane that folds back on itself to form a two-layered membranous pleural sac. The outer layer is called the parietal pleura and attaches to the chest wall. The inner layer is called the visceral pleura and covers the lungs, blood vessels, nerves, and bronchi.

Detailed explanation-3: -The hilum of the lung is found on the medial aspect of each lung, and it is the only site of entrance or exit of structures associated with the lungs. That is to say, both lungs have a region called the hilum, which serves as the point of attachment between the lung root and the lung.