支气管解剖

II Tracheobronchial Tree (Figure 6-3)

● The trachea is a tube composed of 16 to 20 U-shaped hyaline cartilages and the trachealis muscle.气管由透明软骨和肌肉构成

● The trachea begins just inferior to the cricoid cartilage (C6 vertebral level) and ends at the sternal angle (T4 vertebral level), where it bifurcates分支 into the right main bronchus and the left main bronchus.气管从环状软骨下到胸骨角，在这儿左右支气管分叉

● At the bifurcation of the trachea, the last tracheal cartilage forms the carina分叉处有气管隆突, which can be observed by bronchoscopy as a raised ridge of tissue in the sagittal plane.

● The right main bronchus is shorter and wider and turns to the right at a shallower angle than the left main bronchus. 右主支气管短宽角度小 The right main bronchus branches into 3 lobar bronchi (upper, middle, and lower) and finally into 10 segmental bronchi.右主分三个肺叶 10个肺段

● The left main bronchus branches into 2 lobar bronchi (upper and lower) and finally into 8 to 10 segmental bronchi. The branching of segmental bronchi corresponds to the bronchopulmonary segments of the lung. 左主分两叶，8-10段

1. Compression of the Trachea压迫气管 may be due to an enlargement of the thyroid gland or due to an aortic arch aneurysm. 甲状腺肿大主动脉弓动脉瘤The aortic arch aneurysm may tug on the trachea with each cardiac systole such that it can be felt by palpating the trachea at the sternal notch.

2. Distortions in the Position of the Carina气管隆突畸形 may indicate metastasis of bronchogenic carcinoma支气管肺癌转移 into the tracheobronchial lymph nodes that surround the tracheal bifurcation or may indicate enlargement of the left atrium.左心房扩大 The mucous membrane covering the carina is very sensitive in eliciting the cough reflex.咳

3. Aspiration of Foreign Objects误吸

a. When a person is sitting or standing.站或坐

● Aspirated material most commonly enters th e right lower lobar bronchus and lodges within the posterior basal bronchopulmonary segment (no. 10) of the right lower lobe.右肺下叶前基底段

b. When a person is supine.仰卧

● Aspirated material most commonly enters the right lower lobar bronchus and lodges within t he superior bronchopulmonary segment (no. 6) of the right lower lobe.右下叶上段

c. When a person is lying on the right side.右侧卧

● Aspirated material most commonly enters the right upper lobar bronchus and lodges within the posterior bronchopulmonary segment (no. 2) of the right upper lobe.右上叶后段

d. When a person is lying on the left sid

e.左侧卧

● Aspirated material most commonly enters the left upper lobar bronchus and lodges within the inferior lingular (no. 5) bronchopulmonary segment of the left upper lobe.左下叶舌段