68 TOPOGRAPHIC AND APPLIED ANATOMY. 



FIG. 26. A median sagittal section of the neck (formalin preparation). 



larynx between the trachea and the esophagus are the two motor laryngeal nerves, the inferior 

 or recurrent laryngeal nerves (see page 67). 



In the middle line of the neck there is occasionally a superficial median vein. As a rule, 

 however, the more or less prominent anterior jugular veins lie to either side of the median line in 

 the anterior cervical region. They commence in the mental region, run downward upon the 

 infrahyoid muscles, and pass beneath the origin of the sternocleido muscles to empty, together 

 with the external jugular veins, into the subclavian vein. In the median line above the sternum 

 the two veins are united by a transverse vein (the arcus venosus juguli) which is endangered in the 

 operation of low tracheotomy. The left innominate vein (see page 112) only exceptionally projects 

 above the upper margin of the sternum, and consequently is not usually endangered in operative 

 procedures. The external jugular vein runs downward upon the sternocleidomastoid muscle in 

 the lateral cervical region, and during life is often visible through the skin (see page 62). Below 

 the ear it anastomoses with the posterior division of the temporo-maxillary vein; it collects the 

 blood from the occipital and posterior auricular veins and empties into the subclavian vein above 

 the clavicle to the outer side of the attachment of the sternocleidomastoid muscle (where it may 

 be compressed see page 62). If the tendon of the sternocleidomastoid is divided above the 

 clavicle for torticollis, care should be taken to avoid injuring the external jugular vein. The 

 origin of this muscle from the sternum and from the clavicle also conceals the more deeply situated 

 vessels of this region. The common carotid artery may be ligated between the two heads of the 

 muscle, but on account of its depth in this situation the vessel is reached with much greater dif- 

 ficulty than at the level of the cricoid cartilage (see page 62). There is little danger of wounding 

 the common carotid artery in the operation for torticollis. If we penetrate between the two heads 

 of the sternocleidomastoid muscle, we come upon the internal jugular vein; this must be pushed 

 outward, and the sternohyoid and sternothyroid muscles inward, to expose the common carotid 

 artery (see Fig. 27). The vagus nerve must be carefully avoided (see page 64). 



In the lateral cervical region the majority of the nerves originating in the cervical plexus 

 are visible at the posterior margin of the sternocleidomastoid muscle, while the plexus itself, 

 formed by the anterior divisions of the four upper cervical nerves, is concealed by this muscle. 

 The following cutaneous nerves may be seen: 



1. The occipilalis minor nerve, which runs close to the insertion of the sternocleidomastoid 

 muscle to the lateral portion of the occipital region. It may be superficially or deeply placed, is 

 often double, and frequently inosculates with the occipitalis major nerve (see page 28). 



2. The auricular is magnus nerve, larger than the preceding and appearing below it at the 

 margin of the sternocleidomastoid muscle. It runs directly upward to the ear upon the sterno- 

 cleidomastoid muscle, supplies the skin of the auricle, that of the anterior and posterior auricular 

 regions, and also the cutaneous lining of the external auditory meatus. It frequently divides into 

 an anterior and a posterior branch. 



3. The superficialis colli nerve (dividing into a superior and an inferior branch) runs anteriorly 

 at right angles to the sternocleidomastoid muscle and pierces the platysma in order to reach the 

 skin. It is divided, usually at the anterior margin of this muscle, in exposing the great vessels 

 of the neck. Its upper branches inosculate with the cervical branches of the facial nerve. 



