好发于肺上叶尖段、后段及下叶背段。 可能因为人体直立时，两肺的上叶尖后

Occurs in the apical, posterior and dorsal segments of the upper lobe of the lung. It may be because when the human body is upright, the blood pressure of the posterior segment of the upper lobe and the lower segment of the lower lobe of the lungs is low, the blood circulation is poor, and the macrophages are reduced, resulting in low resistance to local resistance. Moreover, there is a lot of oxygen in these parts, and the tuberculosis bacteria are aerobic bacteria.

Good hair in the upper lobe tip of the lungs, the back section and the lower back section. May be due to the human body erect, the upper tip of the two lungs and the lower back section of the lower leaf lower blood pressure, poor blood circulation, macrophages reduced, resulting in low resistance to local resistance. Moreover, these areas have a lot of oxygen, TB bacteria are aerobic bacteria, therefore, in these areas of TB bacteria easy to accumulate.

It is more common in the apical, posterior and dorsal segments of the upper lobe. It may be that when the human body is upright, the blood pressure in the posterior segment of the upper lobe tip and the dorsal segment of the lower lobe is low, the blood circulation is poor, and the macrophages are reduced, resulting in low resistance to local attack. Moreover, there is much oxygen in these parts, and the tuberculosis bacteria are aerobic bacteria. Therefore, the tuberculosis bacteria are easy to gather in these parts.<br>