NECK. 127 



flattened from above below. Connections : In the neck^ 

 with the oesophagus, carotid arteries, pneumo-gastric,. 

 sympathetic and recurrent nerves ; in the thorax, 

 above to the longus colli and oesopliagus, below to the 

 bronchial trunks, the anterior aorta, anterior vena cava,, 

 cardiac and recurrent nerves, base of the heart ; on tlie 

 sides, to the inferior cervical ganglion of the symp- 

 athetic, to tlie vertebral, superior cervical and dorsal 

 arteries and to the antei'ior mediastinum ; on the right 

 to the vena az3^gos ; on the left, to tlie cross of the 

 aorta and the thoracic duct. Structure : It consists of 

 about fifty cartilaginous rings, united by inter-cartila- 

 ginous ligament, lined by a mucous membrane covered 

 by ciliated epithelium, containing muscular fibres, and 

 receiving blood vessels from the carotid and the bron- 

 chial trunks, nerves from the recurrent and sympathe- 

 tic. 



Qilsophagiis. — Form : A long membranous tube con- 

 necting the pharynx with the stomach, it is placed 

 above and to the left of the trachea, passes into the 

 thorax over the base of the heart, to the right pillar of 

 the diaphragm, terminating at the stomach in the car- 

 diac opening. Connections : At its origin, is situated 

 between the guttural pouches and the larynx ; in the 

 neck, above between the trachea and the longus colli ; 

 on each side the carotid artery and its nerves ; below, 



