This section is from the book "Applied Anatomy: The Construction Of The Human Body", by Gwilym G. Davis. Also available from Amazon: Applied anatomy: The construction of the human body.
The oesophagus runs from the level of the cricoid cartilage to the stomach. The cricoid is opposite the sixth cervical vertebra and the cardiac or oesophageal end of the stomach is opposite the lower border of the tenth thoracic vertebra. It is in the median line above, then curves slightly to the left until the root of the neck is reached, when it returns to the median line opposite the fifth thoracic vertebra.
It is in front of the spine and the prevertebral fascia. The layer of fascia between its anterior surface and the trachea is extremely thin. On each side are the common carotid arteries and the sheath of the vessels. The right recurrent laryngeal nerve winds around the commencement of the first portion of the subclavian, and passes inward and upward behind the common carotid artery to reach the groove between the trachea and oesophagus in which it ascends to the larynx.
On the left side the recurrent laryngeal nerve winds around the arch of the aorta and ascends in the groove on the left side between the trachea and oesophagus. The left carotid artery is closer to the oesophagus than the right. The narrowest point of the lumen is at the cricoid cartilage. Its next narrow point is where it crosses the aorta and left bronchus. This is opposite the upper part of the second piece of the sternum or the upper border of the fifth thoracic vertebra. The third narrow portion is the cardiac opening into the stomach. Mouton (Tillaux, "Anat. Topograph.," p. 418) gives the diameter of the oesophagus at each of these three points as 14 mm.
Foreign bodies if they pass the cricoid cartilage are most liable to stop at the aorta and the left bronchus. This is opposite the angle of Ludwig and the second rib, so that the foreign body is either at the root of the neck or just below the top of the sternum. If it passes the two upper constrictions it will probably pass the third, because the cardiac constriction is caused by the diaphragm, which relaxes and allows the body to enter the stomach.
Fig. 186. - Relations of the cervical portion of the oesophagus, viewed posteriorly.
In operating, an incision is made along the anterior border of the left sternomastoid muscle from the sternoclavicular joint upward. The anterior jugular vein will be cut. After opening the deep fascia the sternomastoid is to be pulled outward. The omohyoid is to be drawn up and out and also the lower portion of the sternohyoid and perhaps the sternothyroid.
The middle thyroid and perhaps an accessory thyroid vein are divided and the thyroid gland and trachea drawn inward. The trachea is to be identified by the sense of touch. The inferior thyroid artery is behind the sheath of the vessels and is so high that it is not likely to be injured. The recurrent laryngeal nerve must be looked for between the oesophagus and trachea, and avoided. In going deep down care must be taken not to injure the innominate vein, which comes well up towards the top of the sternum.