THE TRIANGLES OF THE NECK 607 



colli muscle below and by the Scalenus anticus muscle above, between which 

 muscles the vertebral artery and vein will be found passing into the foramen of 

 the transverse process of the sixth cervical A ertebra. A small portion of the origin 

 of the Rectus capitis anticus major may also be seen on the floor of the space. 



The common carotid artery is enclosed within its sheath, together with the 

 internal jugular vein and vagus nerve; the vein lying on the outer side of the 

 artery on the right side of the neck, but overlapping it below on the left side; 

 the nerve lying between the artery and vein, on a plane posterior to both. In 

 front of the sheath are a few filaments descending from the loop of communication 

 between the descendens and communicans hypoglossi; behind the sheath are seen 

 the inferior thyroid artery, the recurrent laryngeal nerve, and the sympathetic 

 cord; and on its inner side, the trachea, the thyroid gland much more prominent 

 in the female than in the male and the lower part of the larynx. By cutting into 

 the upper part of this space and slightly displacing the Sternomastoid muscle 

 the common carotid artery may be tied below the Omohyoid muscle. 



The superior carotid triangle, or the triangle of election, is bounded, behind, by 

 the Sternomastoid; below, by the anterior belly of the Omohyoid; and above, 

 by the posterior belly of the Digastric muscle. It is covered by the integument", 

 superficial fascia, Platysma, and deep fascia, ramifying between which are branches 

 of the facial and superficial cervical nerves. Its floor is formed by parts of the 

 Thyrohyoid and Hyoglossus muscles, and the Inferior and Middle constrictor 

 muscles of the pharynx. This space, when dissected, is seen to contain the upper 

 part of the common carotid artery, which bifurcates opposite the upper border 

 of the thyroid cartilage into the external and internal carotid* These vessels are 

 occasionally somewhat concealed from view by the anterior margin of the Sterno- 

 mastoid muscle, which overlaps them. The external and internal carotid lie 

 side by side, the external being the more anterior of the two. The following 

 branches of the external carotid are also met with in this space, the superior thyroid 

 running forward and downward, the lingual directly forward, the facial forward 

 and upward, the occipital backward, and the ascending pharyngeal directly up- 

 ward on the inner side of the internal carotid. The veins met with are the internal 

 jugular, which lies on the outer side of the common and internal carotid arteries, 

 and veins corresponding to the above-mentioned branches of the external carotid 

 viz., the superior thyroid, the lingual, facial, ascending pharyngeal, and some- 

 times the occipital, all of which accompany their corresponding arteries and ter- 

 Jiiinate in the internal jugular. The nerves in this space are the following: In 

 front of the sheath of the common carotid is the descendens hypoglossi. The hypo- 

 glossal nerve crosses both the internal and external carotids above, curving around 

 the occipital artery at its origin. Within the sheath, between the artery and vein, 

 and behind both, is the vagus nerve; behind the sheath, the sympathetic cord. 

 On the outer side of the vessels the spinal accessory nerve runs for a short dis- 

 tance before it pierces the Sternomastoid muscle; and on the inner side of the 

 external carotid, just below the hyoid bone, may be seen the internal branch of 

 the superior laryngeal nerve; and, still more inferiorly, the external branch of the 

 sa me nerve. The upper part of the larynx and Jower part of the pharynx are 

 also found in the front part of this space. 



The submaxillary triangle corresponds to the part of the neck immediately beneath 

 the body of the mandible. It is bounded, above^ by the lower border of the body of 

 the mandible and a line drawn from its angle to the mastoid process; below, by the 

 posterior belly of theJDigastric muscle and the Stylohyoid muscle; in front, by the 

 anterior belly of the Digastric. It is covered by the integument, superficial fascia, 

 Platysma, and deep fascia, ramifying between which are branches of the facial 

 and ascending filaments of the superficial cervical nerves. Its floor is formed 

 by the Mylohyoid and Hyoglossus muscles. This space contains, in front, the 



