5. Anatomy of Trachea.pdf

ANATOMY OF TRACHEA (WINDPIPE) STRUCTURE ASSOCIATED LECTURE/ LAB PHOTOS - It is a cartilaginous and membranous tube forming the beginning of the lower respiratory tract - It is kept patent by the anterior C-shaped cartilaginous ring...

ANATOMY OF TRACHEA (WINDPIPE) STRUCTURE ASSOCIATED LECTURE/ LAB PHOTOS - It is a cartilaginous and membranous tube forming the beginning of the lower respiratory tract - It is kept patent by the anterior C-shaped cartilaginous rings, and the posterior membranous part permits expansion of the oesophagus during the passage of bolus of food - It is 4-6 inches in length, upper half lies in the neck and the lower half in the superior mediastinum - The lumen is smaller in the living than in the cadaver - It begins at the lower border of cricoid cartilage (C6), as the continuation of larynx - It ends at the lower border of the T4 (sternal angle) by dividing into two principal bronchi. In the living subjects, in erect posture, the trachea bifurcates at the lower border of T6 - In its course it mostly lies in the median plane except at the lower end where it deviates slightly to the right - Develops from laryngo-tracheal diverticulum STRUCTURE OF TRACHEA - It is made up of fibro-elastic wall supported by C-shaped cartilaginous skeleton - The rings are about 16-20 in number, the last tracheal ring is called carina - The gap of the C shaped ring is closed by fibro-elastic membrane and trachealis muscle - The mucous membrane is lined by ciliated columnar epithelium - The submucosa is rich in mucous and serous glands BLOOD SUPPLY - Cervical part of the trachea is supplied by branches coming from inferior thyroid artery VEINS - Drain into left brachiocephalic vein LYMPHATICS - Pretracheal and paratracheal lymph nodes NERVE SUPPLY Parasympathetic supply: is by recurrent laryngeal through vagus, which is motor to trachealis and secretomotor to mucous membrane Sympathetic supply: is from the middle cervical sympathetic ganglion, which reach through inferior thyroid arteries, and are vasomotor