Trachea are generally highly elastic but they may calcify with age. The trachealis muscle connects the ends of the incomplete rings and contracts during coughing, reducing the size of the lumen of the trachea to increase the rate of air flow. The esophagus lies posteriorly to the trachea, adjoining along the tracheoesophageal stripe. Circular horizontal bands of fibrous tissue called the annular ligaments of trachea join the tracheal rings together. The cartilaginous rings are incomplete to allow the trachea to collapse slightly so that food can pass down the esophagus. A flap-like epiglottis closes the opening to the larynx during swallowing
History of beliefs about the human body muscular and focuses on the exterior of the body, what can be see and felt. This was the standard of beauty of humans and continues to be the ideal body of European traditions. There is no Vitruvian women. Eastern ideologies of the body explain what can be detected, not only felt and examined. This comes from the idea that there is not only what can be physically seen and touched but what can't be. Energy or more aptly the means by which your body can manifest itself in the world can't be seen but, was thought to be able to