THE NECK. 133 



tissues beneath the tongue and jaw around the submaxillary gland and the upper 

 portion of the neck. It is a dangerous affection and may cause death not only by 

 sepsis but also by oedema of the larynx. 



Dr. T. Turner Thomas {Annals of Surgery, February and March, 1908), has 

 pointed out that the infection passes from the inside of the mouth to the submaxil- 

 lary region outside by following the connective tissue around the submaxillary gland 

 as it winds around the posterior edge of the mylohyoid muscle through the opening 

 existing between this muscle in front and the anterior portion of the middle constrictor 

 of the pharynx behind. 



The SUPERIOR CAROTID TRIANGLE is limited posteriorly by the sternomastoid 

 muscle, superiorly by the posterior belly of the digastric, and inferiorly by the anterior 

 belly of the omohyoid. The location of the omohyoid muscle can be determined 

 by that of the cricoid cartilage, as the muscle crosses the common carotid artery 

 about opposite that point. The sternomastoid muscle can be both seen and felt. 

 It is attached above from the apex of the mastoid process to the middle of the 



^^^^^^^^^ Superior constrictor 



Hypoglossal nerve- 



Mylohyoid --^ r - -,^^^^^,. -Parotid gland 



.. Styloglossus 



Submaxillaiy gland (su-- n^ .n^^ ! 

 perficial portion removed) "^^^WKbT^^Sfr A^L ^9^B P Middle constrictor 



_ _^- 



Stylohyoid (tendon) 



Hyoid bone 

 Thyrohyoid 



Inferior constrictor 

 Omohyoid 



Sternomastoid 

 Sternohyoid 



FIG. 165. Submaxillary region. -The anterior portion of the submaxillary gland is seen winding around 

 and beneath the posterior edge of the mylohyoid muscle. The posterior portion of the gland has been cut 

 away. The posterior belly of the digastric and the Stylohyoid muscles have also been removed. 



superior curved line on the occipital bone. It is attached below by a sternal head 

 to the upper anterior part of the first piece of the sternum, and by a clavicular head 

 to the inner third of the clavicle on its superior and interior border. Its action will 

 be mentioned in discussing wry-neck. 



Arteries. -The carotid arteries and their branches are found in this triangle. 

 The line of the carotid arteries is from a mid-point between the mastoid process and 

 the angle of the jaw to the sternoclavicular articulation. The line of the sterno- 

 mastoid muscle is from the mastoid process to near the middle of the upper edge 

 of the sternum. Thus the carotids are internal to the anterior edge of this muscle above, 

 behind the angle of the jaw, and external to it below. The common carotid at its 

 upper portion it ends opposite the upper border of the thyroid cartilage is just 

 about at or close to the edge of the sternomastoid muscle. From the thyroid car- 

 tilage up are the internal and external carotids. The internal lies behind and to 

 the outer side of the external. The internal gives off no branches until it reaches 

 the skull, while the external is practically all branches. Sometimes the external and 

 the internal carotids are covered by the anterior margin of the sternomastoid muscle. 

 The branches of the external carotid are the superior thyroid, ascending pharyngeal, 

 lingual, facial, occipital, posterior auricular, internal maxillary, and temporal. The 



