It is convenient to describe with the head the part of the neck that lies ventral to the vertebrae.

The dorsal part of the neck will be dealt with in the next chapter. The skin on the ventral surface of the neck is loose and in some breeds forms longitudinal folds. Subcutaneous fat tends to be concentrated caudally, especially in the depression dorsolateral to the manubrium.

The external jugular vein sinks into this depression after following a course along the lateral surface of the sternocephalic muscle (see Figure 2-42). It does not lie in a distinct jugular groove as in the larger species. Although it is the principal vein draining the head, it is assisted by small vessels associated with the vertebrae (vertebral vein, internal vertebral plexus) and accompa­nying the common carotid artery (internal jugular vein) (see Figure 11-46, A-B); these mainly drain deeper structures. The external jugular vein is formed by tribu­taries embracing the mandibular gland; these are easily raised by pressure on the jugular and provide an addi­tional means for the positive distinction of the gland from the mandibular lymph nodes (see Figure 11-6). The large diameter of the jugular vein makes it a con­venient alternative to the cephalic when considerable amounts of bloods have to be collected. It is especially useful in the cat, in which the limb veins are naturally small.

Parts of the hyoid and larynx can be palpated imme­diately caudal to the angle of the mandible. The trans­verse basihyoid, the most rostral component, is flanked by the ceratohyoid bones, which project forward, and the thyrohyoids, which pass obliquely caudally. Two further prominences, easily identifiable in the midline, are the thyroid prominence and the cricoid cartilage.