THE CESOPHAGUS 



351 



through this it terminates at once at the cardiac orifice of the stomach, at the level 

 of the fourteenth thoracic vertel)ra, a little to the left of the median plane, and 

 about four or five inches (ca. 10 to 12 cm.) ventral to the vertebral colunni. 



Viewed with reference to the frontal plane, its course^ is downward and back 

 ward till it enters the thorax and passes upward to gain the dorsal face of the trachea. 

 For a short distance (i. e., to the root of the lung) its direction is almost horizontal; 



Tetu jHirtd wii-sclc 



Nerves III, 

 IV, VI, and 



opJiUiulmic 



Itdcrnnl tnaxil- 



larij artery 



Transverse 

 facial nerve 

 Buccinator 

 nerve 

 Inferior maxil- 

 lary nerve 

 Inferior al- 

 veolar artery 



Great cornu of 

 hyoid hone 



Lingual branch 

 of IX nerve 



External max- 

 illary artery 



Hypoglossal 



nerve 



Masseteric 



vessels 



Thyroid cornu of 

 hyoid bone 



Parotid duct 



Lytnj>h gland. 



Coronoid process 



Transverse fa- 

 cial vessels 

 Transverse fa- 

 cial nerve 

 External ptery- 

 goid muscle 



Internal max- 

 illary vein 

 Internal ptery- 

 goid muscle 

 Ratnus of 

 mandibh' 

 Hyo-pharyn- 

 geus muscle 

 Istltmus fau- 

 cium 

 Tonsil 

 Digast7-icus 

 {intermed. ten- 

 don) 



Anterior end of 

 submaxillary 

 gland 



Lingual vein 



External max- 

 illary vein 



Fig. 255. — Cross-section of Head of Horse. 

 The .section passes through the temporo-mandibular articulation, but is slightly obliciue. 1, Corpu.s cal- 

 losum; ^, lateral ventricle of brain; oJ, caudate nucleus; >^, internal capsule; 5, lenticular nucleus; 6, optic ehiasnia; 

 7, middle cerebral artery; 8, .sphenoidal sinuses; 9, cavernous sinus; 10, Eustachian tube, inner lamina; //, 11, 

 guttural pouches; 12, soft palate; 13, epiglottis; 14, hyo-epiglottic muscle; lo, thyro-hyoid muscle. 



behind this it passes somewhat upward to its termination. The cervical part of 

 the tube is about four to six inches (10 to 15 cm.) longer than the thoracic part, 

 while the so-called abdominal part is about an inch (2 to 3 cm.) long.^ 



^ Careful observations (especially on frozen sulijects and those in which the ors;ans have been 

 hardened in situ) show that there is no abdominal part of the a'sophagiis in the strict sense of the 

 term. The stomach here lies directly on the diaphragm, so that the last inch or so of the oesopha- 

 gus is placed obliquely in the hiatus cesophageus, and is partly covered by the pleura, l)Ut not by 

 peritoneum. In soft subjects the weight of the stomach, or traction on it, draws part of the 

 oesophagus into the abdomen, inclosed in a collar of peritoneum. 



