THE NECK. 17 



easily compressed for a short time against the spine about the 

 level of the cricoid cartilage. The artery extends (generally) 

 as high as the upper border of the thyroid cartilage and 

 corresponds with a line drawn from the sterno-clavicular 

 joint to midway between the angle of the jaw and the 

 mastoid process. 



Between the sternal origins of the sterno-mastoid is the 

 fossa above the sternum, more or less perceptible in different 

 necks. As it heaves and sinks alternately, especially in dis- 

 tressed breathing, it was called by the old anatomists 'fonticulus 

 gutturis.' In beautiful necks, as seen in the ' Venus," it is filled 

 up by fat. 



Notice the interval between the sternal and clavicular 

 origins of the sterno-mastoid. A knife introduced a very 

 little way into this interval would wound, slanting inwards, 

 the common carotid, slanting outwards, the internal jugular 

 vein. These facts are of importance in performing the 

 subcutaneous section of the tendon of this muscle. 



29. Sterno-clavicular joint. Many important parts lie 

 behind the sterno-clavicular joint. There is the commence- 

 ment of the vena innominata ; behind this comes the common 

 carotid on the left side, and the division of the arteria 

 innominata on the right. Deeper still, the apex of the lung 

 rises into the neck. 



In a child the arteria innominata often lies in front of the 

 trachea and divides a little higher than the joint : a point to 

 be remembered in tracheotomy (27). 



30. Apex of lung- in the neck. The extent to which 

 the apex of the lung rises into the neck is greater than is 

 generally supposed. Many observations in reference to this 

 point lead to the conclusion that the lung rises behind the 

 sterno-mastoid, on an average, one inch and a half above the 

 clavicle ; in persons with long necks, as much as two inches. 

 The apex of the lung and pleura is covered by the clavicular 

 origin of the sterno-mastoid, the sterno-thyroid, and a part 

 of the scalenus anticus. It is also crossed by the subclavian 

 vessels in the first part of their course. As this cervical 

 portion of lung is peculiarly liable to tubercular disease, it 



C 



