fiOO DISSECTION OF THE NECK. 



course ; internal branches. The course of the artery is along the side of the 

 trachea and larynx, gradually diverging from the vessel on the 

 opposite side in consequence of the increasing size of the larynx ; 



^situation, and its direction is marked by a line from the sterno-clavicular 

 articulation to a point midway between the angle of the jaw and 

 the mastoid process. 



Contained in a sheath of cervical fascia with the internal jugular 

 vein and the pneuino-gastric nerve, the common carotid artery has 



Parts the following connections with the surrounding parts : As high as 



covering it, ^g cricoid cartilage the vessel is deeply placed, and is concealed by 

 the common coverings of the skin, platysma, and fascise ; and by the 

 muscles at the lower part of the neck, viz., stern o-mastoid (sternal 

 origin), sterno-hyoid, omo-hyoicl, and sterno- thyroid. But from the 

 cricoid cartilage to its termination the artery is more superficial, being 

 covered only by the sterno-mastoid and the common investments of 



beneath it, the neck. The vessel rests mostly on the longus colli and scalenus 

 an tic us muscles, but close to its ending on the rectus capitis anticus 



and on its major. To the inner side of the carotid lie the trachea and larynx, 



sides. kh e oesophagus and pharynx, and the thyroid body, the last over- 



lapping the vessel by the side of the larynx. Along the outer side 

 of the carotid sheath is a chain of lymphatic glands. 



Position of Veins. The large internal jugular vein lies on the outer side of 



veins, ^ e ar ^ er y } "being closely applied to it in the upper part of its course, 



but separated from it below by an interval about half an inch wide : 

 on the left side the vein is nearer to the artery below and is even 

 sometimes placed over it. One or two superior thyroid veins cross 

 the upper end of the arterial trunk ; and opposite the thyroid body 

 another small vein (middle thyroid) is directed backwards over the 

 vessel. Near the clavicle the anterior jugular vein passes outwards 

 in front of the artery, but is separated from it by the sterno-hyoid 

 and sterno-thyroid muscles. 



of arteries, Arteries. An offset of the superior thyroid artery to the sterno- 

 mastoid descends over the upper part of the sheath ; and the 

 inferior thyroid crosses behind it near the lower border of the 

 cricoid cartilage. 



of nerves to Nerves. The descendens cervicis branch of the hypoglossal lies 



carotid 



in front of the artery, crossing from the outer to the inner side, 

 and is joined there by the communicating branches from the 

 cervical plexus. The pneumo-gastric lies within the sheath behind 

 and between the artery and the vein. The sympathetic cord and 

 its branches rest on the spine behind the sheath. All the nerves 

 above mentioned have a longitudinal direction ; but the inferior 

 or recurrent laryngeal crosses obliquely inwards beneath the sheath, 

 towards the lower end of the artery. 



Branches As a rule, the common carotid artery does not furnish any 



collateral branch, though it is very common for the superior 

 thyroid to spring from its upper end. At the terminal bifurcation 

 into the two carotids the artery is slightly bulged. 



Internal The INTERNAL JUGULAR VEIN extends upwards to the base of the 



ir vein gj^j^ ^ ut on j v fa Q p art O f ^ ^at accompanies the common carotid 



