604 



DISSECTION OF THE NECK. 



maxillary vein lies on it, and the anterior division of this trunk 

 frequently runs with the artery beneath the digastric muscle. 

 Near the beginning it is crossed by the facial and lingual veins 

 joining the internal jugular vein. 



and nerves. Nerves are directed from behind forwards over and under the 

 artery. At the lower border of the digastric the hypoglossal lies 

 over the vessel, and above that muscle it is crossed by the. two 

 divisions of the facial nerve. Three nerves lie beneath it begin- 

 ning below, the small external laryngeal; a little higher, tl 

 superior laryngeal ; and near the angle of the jaw, the gl 

 pharyngeal. 



The BRANCHES of the external carotid are numerous, and are 

 classed into anterior, posterior, and ascending sets. The anterior 

 set comprises branches to the thyroid body, the tongue, and the 

 face, viz., the superior thyroid, lingual, and facial arteries. In the 

 posterior set are the occipital and posterior auricular branches. 

 And the ascending set includes the ascending pharyngeal, super- 

 ficial temporal, and internal maxillary arteries. Besides these, the 

 external carotid gives other branches to the neighbouring muscles 

 and to the parotid gland. 



The arrangement of the branches of the carotid may be altered by 

 their closer aggregation on the trunk. The usual number may be 

 diminished by two or more uniting into one ; or it may be increased 

 by some of the secondary offsets being transferred to the parent 

 trunk. 



Directions. All the branches, except the ascending pharyngeal, 

 lingual and internal maxillary, may now be examined ; but those 

 three will be described afterwards with the regions they occupy. 



The SUPERIOR THYROID ARTERY (e] arises near the great cornu of 

 the hyoid bone, and passes beneath the omo-hyoid, sterno-hyoid 

 and sterno-thyroid muscles to the thyroid body, to which it is dis- 

 tributed chiefly on the anterior aspect. This artery is superficial 

 in the anterior triangle, and furnishes offsets to the lowest con- 

 strictor muscle of the pharynx and to the muscles beneath which it 

 lies, in addition to the following named branches : 



a. The hyoid branch is very small, and runs inwards below the 

 hyoid bone : it supplies the muscles attached to that bone, and 

 anastomoses with the vessel of the opposite side. 



6. A sterno-mastoid branch descends in front of the sheath of the 

 common carotid artery, and is distributed chiefly to the muscle 

 from which it takes its name. 



c. The superior laryngeal artery pierces the membrane between 

 the hyoid bone and the thyroid cartilage, with the superior 

 laryngeal nerve, and ends in the interior of the larynx. 



d. A small crico-thyroid branch is placed on the membrane be- 

 tween the cricoid and thyroid cartilages, and communicates with the 

 corresponding artery of the opposite side, forming an arch. 



The superior thyroid vein commences in the larynx and the thyroid 

 body, and crosses the end of the common carotid artery to open into 

 the internal jugular vein. 



Its branches 

 are anterior, 



posterior, 



and ascend- 

 ing: 



rhan.uvs in 

 origin 



and in 

 number. 



Branches 

 now seen 

 are 



Superior 

 thyroid 



has these 

 offsets ; 



the hyoid 

 branch, 



to sterno- 



mastoid 

 muscle, 



to larynx, 



to crico- 

 thyroid 

 membrane. 



Accompany 

 ing vein. 



; 



re 

 " 



