HEAD AND NECK IN SECTION 19 



boundary of the foramen having been removed. In the notch is placed 

 the retrograde or anastomotic branch of the occipital artery, which after 

 passing through the foramen inosculates with the terminal branch of 

 the vertebral artery. Inferiorly to the atlas are the prevertebral muscles 

 (the rectus capitis anticus and the longus colli) which separate the bone 

 from the superior surface of the oesophagus. The latter is here quite 

 in the median line, and superposed to the trachea, and the corrugated 

 appearance of its lining membrane is quite evident. 



Externally to the oesophagus is the carotid artery, on the superior 

 aspect of which is placed the common nervous trunk formed by the 

 pneumogastric nerve and the cervical cord of the sympathetic. 

 Inferiorly and here slightly to the inner side of the artery is the 

 inferior (recurrent) laryngeal branch of the pneumogastric. 



The jugular vein is placed about half an inch externally to the 

 carotid artery, for this is the situation where the vein is approaching 

 the artery after having pierced the parotid gland, and coursed along its 

 outer surface near its postero-inferior angle. 



The superior surface of the trachea is flattened, and in outline the 

 lumen of the tube approaches the elliptical. 



On the inferior surface of the trachea the sterno-thyro-hyoideus, and 

 the subscapulo-hyoideus, or pre-tracheal muscles, are situate, and they 

 will be observed to form quite a thin broad sheet. 



Plate VIII. (facing page 22) represents a transverse vertical section 

 taken across the base of the neck. The section passes through the 

 seventh cervical vertebra, which is seen almost in the centre of the 

 plate, and which is readily recognised by the height of its superior 

 spinous process. 



Extending upwards from the tip of the process are the two sheet-like 

 or lamellar portions of the ligamentum nucha?. These are closely 

 applied to one another, and their width (/>., the distance from the 

 funicular portion to the vertebral column) is very much greater than 

 near the upper extremity of the neck. Above the lamellar portion of 



