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 as Traditional chinese medicine, or western, which follows the Greek traditions of science and is more closely related to modern science despite original anatomists and ideas of the body being just as unscientific as Chinese practices. In Western historical research, scholars began investigating the cultural history of the human body in detail in the 1980s. The movement is particularly associated with the historian of medicine Roy Porter, whose 1991 article 'History of the Body' was a seminal study. 1995 saw the foundation of the journal "Body and Society", by which time the field of the history of the body was