Tue HEAD AND NECK. 239 
The two muscles are closely associated in the middle line. They 
should be separated from one another and divided. 
(g) 
(h) 
(i) 
(3) 
(k) 
(I) 
(m) 
(n) 
(0) 
The sternothyreoideus. Origin: In common with the 
sternohyoideus. Insertion: Lateral plate of the thyreoid 
cartilage of the larynx. The muscle forms a thin band 
lying on the side of the trachea. It is continued from the 
thyreoid cartilage to the greater cornu of the hyoid as the 
thyreohyoideus. 
The trachea occupies a median position, and is supported by 
cartilaginous tracheal rings. 
The thyreoid cartilage of the larynx; a saddle-shaped carti- 
lage, composed of right and left thyreoid plates (Fig. 65). 
The cricoid cartilage, a thick annular cartilage situated 
between the thyreoid cartilage and the first tracheal ring. 
It is connected ventrally with the thyreoid cartilage by the 
cricothyreoideus muscle. 
The deep cervical lymph gland (lymphoglandula cervicalis 
profunda) is a large elongated reddish-colored gland in the 
upper portion of the neck, opposite the thyreoid cartilage. 
The thyreoid gland (gl. thyreoidea) lies on the ventral 
surface of the trachea behind the cricoid cartilage. It is 
composed of right and left portions connected across the 
middle line by a thin median portion, the isthmus. 
The common carotid artery (a. carotis communis) passes 
forward from the superior thoracic aperture along the side 
of the trachea. Its branches on the neck include the 
superior thyreoid artery (a. thyreoidea superior), to the 
thyrecid gland, and the (superior) laryngeal artery 
(a. larnygea). The latter arises at the level of the thyreoid 
plate, passing to the larnyx and to the sternohyoid sterno- 
thryeoid muscles. 
The internal jugular vein (v. jugularis interna) lies to the 
lateral side of the common carotid artery, traversing the 
neck from the jugular foramen of the skull to the superior 
thoracic aperture. 
The tenth cranial or vagus nerve (n. vagus) is the largest 
of four nerves accompanying the carotid artery. It lies to 
the lateral side of the common carotid, between the latter 
