160 Anatomy of the; Rabbit. 



(g) 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. 

 (h) The trachea occupies a median position, and is supported by 



cartilaginous tracheal rings. 

 (i) The thyreoid cartilage of the larynx; a saddle-shaped carti- 

 lage, composed of right and left thyreoid plates (Fig. 36). 

 (j) 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, 

 (k) 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. 

 (1) 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 narrower median portion, the isthmus. 

 (m) 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 th3^reoid 

 gland, and the (superior) laryngeal artery (a. laryngea). 

 The latter arises at the level of the thyreoid plate, passing 

 to the larynx and to the sternohyoid sternothryeoid muscles. 

 (n) 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, 

 (o) 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 and the 

 internal jugular vein. It gives off the n. laryngeus superior 

 to the larynx, the latter passing to the dorsal side of the 

 common carotid artery, 

 (p) The ramus descendens of the twelfth cranial or hypoglossal 

 nerve crosses the root of the vagus from a lateral to a medial 

 position. It passes backward on the ventral surface of the 

 artery, and is chiefly distinguishable by its branches to the 

 sternohyoideus and related muscles, 

 (q) The cervical portion of the sympathetic trunk lies on the 

 dorsal surface of the common carotid, and is slightly medial 

 in relation to the vagus, 

 (r) The ramus cardiacus of the vagus (n. depressor) lies on the 



