478 Anatomy Applied to Medicine and Surgery. 



carotid arteries represents the course of this nerve. 

 Hypo-glossal, From the upper part of the line for 

 the internal carotid artery, in a curved manner, 

 to the tip of the greater cornu of the hyoid 

 bone, thence, with convexity downwards, to the mid- 

 dle of the lower border of the inferior maxilla. The 

 spinal accessory may be represented by a line drawn from 

 the upper end of the carotid line, downwards and back- 

 wards, entering the sterno-mastoid muscle, about one inch 

 below the tip of the mastoid process and emerging from 

 the posterior border of this muscle, at its middle, and then, 

 crossing the occipital triangle, to end in the trapezius 

 about three inches above the level of the clavicle. 

 Phrenic, from the middle of the sterno-mastoid, opposite 

 the upper border of the thyroid cartilage to the sterno- 

 clavicular articulation. 



Operations. Ligation of Vessels. (1) Common 

 Carotid. In connection with the ligation of this vessel, it 

 is worth noting, that, about two and a half inches above 

 the clavicle, and in the line of the artery, there is a promi- 

 nent tubercle, which can be felt on deep pressure. This 

 is termed the carotid tubercle, after Chassoignac, who ad- 

 vised compression of the carotid at this point. The com- 

 mon carotid may be ligated, above or below the point 

 where the omo-hyoid muscle crosses the artery, but, on 

 account of the greater depth of the vessel below this point, 

 the upper part of the artery is generally selected for the 

 purpose of ligation. Operation. An incision, three inches 

 in length, is made in the line of the artery with its centre 

 opposite thecricoid cartilage. The skin, superficial fascia 

 and the platysma with branches of the superficial cervical 

 nerves, having been incised, the deep fascia is opened 

 along the anterior border of the sterno-mastoid muscle. 

 This muscle is drawn outwards and the pulsations of the 



