Anatomy of the Trachea Bronchi & Broncho-Pulmonary Segment

Dr. Vohra

A fibroelastic mobile tube about 5 in long & 1 in diameter with U-shaped hyaline cartilage that keep the lumen patent. The posterior end of the cartilage is connected by smooth muscle TRACHEALIS. Begins in the neck below the cricoid cartilage at the level of C6 and terminates in thorax at the level of the sternal angle (T4), where it divides into right & left principal (main) bronchi. The bifurcation is called as CARINA.

Trachea

Relations in the superior mediastinum Anterior: Sternum, thymus, the left brachiocephalic vein, origin of brachiocephalic artery & common carotid arteries & arch of aorta

Posterior: Esophagus & left recurrent laryngeal nerve

Right side: Azygos vein, the right vagus nerve & pleura Left side: Arch of aorta, the left CCA, subclavian artery, left vagus & left phrenic nerves & pleura

Nerve Supply Vagus, recurrent laryngeal & sympathetic

Principal Bronchi

Right (1cm)The right principal bronchus wider shorter & more vertical than left. Before entering the hilum of the right lung it give of superior lobar bronchus. On entering the hilum, it divides into a middle & an inferior lobar bronchus.

Left (2cm)The left principal bronchus is narrower, longer & more horizontal than right. Passes to the left below the arch of aorta & in front of esophagus. On entering the hilum left bronchus divides into a superior & an inferior lobar bronchus.

A bronchopulmonary segments:Are the anatomical, functional & surgical units of the lungs. Each lobar (secondary) bronchus give off branches called segmental (tertiary) bronchi. Each segmental bronchus passes to a structurally & functionally independent unit of a lung lobe called bronchopulmonary segment

A bronchopulmonary segmentIs pyramid shaped, with the apex at the lung root; Is the largest subdivision of a lobe; Is surrounded by connective tissue; Has separate segmental artery, segmental (tertiary) bronchus, lymph vessels & autonomic nerves; Segmental veins lie in the connective tissue b/w adjacent bronchopulmonary segment;Diseased segment can be removed surgically without affecting the function of other segments

Right Lung Superior Lobe: a three-piece lobe - a posterior and an anterior segment next to one another with an apical segment on top

The main bronchopulmonary segment are:

Middle Lobe: a flat, two-piece lobe that sits on the anterior aspect of the lung a medial and a lateral segment next to one another

Right Lung

Left Lung

Clinical NotesPLEURAL EFFUSION The pleural normally contains 5- 10ml of clear fluid. The formation results from hydrostatic & osmotic pressures. The pleural fluid is normally absorbed by the capillaries of visceral pleura. Any condition that increases the production of fluid result in abnormal accumulation of fluid called as.

PLEURISY or PLEURITIS is the inflammation of pleura PNEUMONIA inflammation of lungsPLEURAL RUB pleural surfaces become rough & produce friction & a can be heard with stethoscopePLEURAL ADHESIONS visceral & parietal pleura adhere to each otherPNEUMOTHORAX air in the pleural cavity (from lungs or chest wall)HYDROPNEUMOTHORAX air in pleural cavity associated with serous fluidPYOPNEUMOTHORAX air in pleural cavity associated pusHEMOPNEUMOTHORAX air in pleural cavity associated with bloodEMPYEMA collection of pus in pleural cavity without air

Clinical NotesCOMPRESSION OF THE TRACHEA bilateral enlargement of thyroid glandAORTIC ARCH ANERYSM dilation of aortic arch TRACHEITIS OR BRONCHITIS give rise to a raw burning sensation felt deep to the sternum instead of actual painINHALED FOREIGN BODIES common in children, tend to enter right bronchus instead of left because the right bronchus is wider & more direct continuation of the tracheaHBRONCHOSCOPY examination of interior of trachea through bronchoscopeTRACHEOSTOMY cutting the trachea