THE NECK. 159 



These latter open into the external jugular i or 2 cm. above the clavicle and are 

 almost certain to be cut in operations in the supraclavicular fossa. An incision 

 along the anterior edge of the sternomastoid low down will cut the anterior jugular 

 vein a short distance above the sternum as it winds beneath the sternomastoid to 

 empty into the external jugular. An incision along the anterior border of the 

 sternomastoid from its middle up is bound to cause free hemorrhage. The external 

 jugular behind the angle of the jaw communicates with the facial, which empties into 

 the internal jugular; hence division of the external jugular at this point also drains 

 the blood almost directly from the internal jugular. A carelessly deep incision may 

 wound the internal jugular itself in the region posterior to the hyoid bone. The 

 internal jugular is more superficial at this point than it is lower down. The temporo- 

 maxillary and posterior auricular veins will also be cut behind the ramus of the jaw. 



Not only are veins cut but also nerves. The middle of the posterior edge 

 of the sternomastoid is the point of departure of several nerves. The superficial 

 cervical runs directly transversely inward toward the thyroid cartilage. The auricu- 

 laris magnus goes up to the lobe of the ear, and the occipitalis minor follows the 

 posterior edge of the muscle up to the occiput. These three nerves are nerves of sen- 

 sation and if they are divided only a certain amount of temporary anaesthesia will be 

 produced over the parts they supply, hence their division is not a matter of much 

 moment. The auricularis magnus is the largest of the three. The descending 

 branches of the cervical plexus, which leave the posterior edge of the sternomastoid 

 muscle immediately below the nerves just mentioned, proceed down under the deep 

 fascia and will be seen only in a deeper dissection. The nerve which it is absolutely 

 important to avoid is the spinal accessory. This enters the sternomastoid muscle 

 on its under surface some little distance back of its anterior edge and 3 to 5 cm. 

 below the mastoid process. It sends a branch to the muscle and leaves its posterior 

 edge about its middle. It then passes downward and outward across the posterior 

 cervical triangle under the deep fascia to enter the deep surface of the trapezius. If 

 this nerve is divided, paralysis of the trapezius will certainly follow and as it is a 

 motor nerve the shoulder of that side will drop considerably. This will be a perma- 

 nent deformity because motor nerves do not seem to have their functions restored 

 by time as so usually occurs when the nerves of sensation are divided. 



If the nodes to be removed are superficial ones there are no other structures to 

 be feared and the operation will be an easy one. If they lie deeper, then the sheath 

 of the sternomastoid muscle is to be divided and the muscle pulled outward. Just 

 above the level of the cricoid cartilage a small artery, the sternomastoid branch of 

 the superior thyroid, enters the muscle and it will be divided. As the sternomastoid 

 is raised and pulled outward care must be taken to avoid wounding the spinal 

 accessory nerve. As this nerve enters the muscle from 3 to 5 cm. below the mastoid 

 process and some distance back from the edge of the muscle, if it is necessary to 

 divide the muscle it is best done high up above the entrance of the nerve, or low 

 down. By so doing the nerve supply (from the spinal accessory) and blood supply 

 are not interfered with and the function of the muscle is not so much impaired as 

 it would be if divided near the middle. The nodes not only possess their own 

 capsule but also a covering from the connective tissue in which they lie. There- 

 fore to remove them they must be detached and separated from it usually by blunt 

 dissection. When these strands of fibrous tissue from the nodes to the surrounding- 

 parts are strong they have to be caught with forceps and cut. They are to be 

 clamped, to avoid possible bleeding. When the angle of the jaw is reached the 

 communicating branch between the facial and external jugular veins must be 

 clamped and cut. The parotid gland is to be pulled upward and inward. The 

 nodes may stick to the jugular vein and carotid artery. The vein is on the outside 

 and is likely to be the first encountered. When distended it overlies the artery. 

 If collapsed its presence may not be suspected. Feel for the pulsation of the carotid 

 artery and avoid the structure just to its outer side. The jugular vein may be so 

 involved in the mass as to necessitate its removal. In such a case remember that 

 posteriorly between it and the carotid artery is the pneumogastric nerve. 



The sympathetic nerve lies deeper in the fascia toward its posterior surface and 

 is not so likely to be wounded. Its superior cervical ganglion lies opposite the 



